代码整理

hooks/storage/badger/badger.go

@@ -0,0 +1,576 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: mochi-co, gsagula, werbenhu
+
+package badger
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	badgerdb "github.com/dgraph-io/badger/v4"
+	"testmqtt/hooks/storage"
+	"testmqtt/mqtt"
+	"testmqtt/packets"
+	"testmqtt/system"
+)
+
+const (
+	// defaultDbFile is the default file path for the badger db file.
+	defaultDbFile         = ".badger"
+	defaultGcInterval     = 5 * 60 // gc interval in seconds
+	defaultGcDiscardRatio = 0.5
+)
+
+// clientKey returns a primary key for a client.
+func clientKey(cl *mqtt.Client) string {
+	return storage.ClientKey + "_" + cl.ID
+}
+
+// subscriptionKey returns a primary key for a subscription.
+func subscriptionKey(cl *mqtt.Client, filter string) string {
+	return storage.SubscriptionKey + "_" + cl.ID + ":" + filter
+}
+
+// retainedKey returns a primary key for a retained message.
+func retainedKey(topic string) string {
+	return storage.RetainedKey + "_" + topic
+}
+
+// inflightKey returns a primary key for an inflight message.
+func inflightKey(cl *mqtt.Client, pk packets.Packet) string {
+	return storage.InflightKey + "_" + cl.ID + ":" + pk.FormatID()
+}
+
+// sysInfoKey returns a primary key for system info.
+func sysInfoKey() string {
+	return storage.SysInfoKey
+}
+
+// Serializable is an interface for objects that can be serialized and deserialized.
+type Serializable interface {
+	UnmarshalBinary([]byte) error
+	MarshalBinary() (data []byte, err error)
+}
+
+// Options contains configuration settings for the BadgerDB instance.
+type Options struct {
+	Options *badgerdb.Options
+	Path    string `yaml:"path" json:"path"`
+	// GcDiscardRatio specifies the ratio of log discard compared to the maximum possible log discard.
+	// Setting it to a higher value would result in fewer space reclaims, while setting it to a lower value
+	// would result in more space reclaims at the cost of increased activity on the LSM tree.
+	// discardRatio must be in the range (0.0, 1.0), both endpoints excluded, otherwise, it will be set to the default value of 0.5.
+	GcDiscardRatio float64 `yaml:"gc_discard_ratio" json:"gc_discard_ratio"`
+	GcInterval     int64   `yaml:"gc_interval" json:"gc_interval"`
+}
+
+// Hook is a persistent storage hook based using BadgerDB file store as a backend.
+type Hook struct {
+	mqtt.HookBase
+	config   *Options     // options for configuring the BadgerDB instance.
+	gcTicker *time.Ticker // Ticker for BadgerDB garbage collection.
+	db       *badgerdb.DB // the BadgerDB instance.
+}
+
+// ID returns the id of the hook.
+func (h *Hook) ID() string {
+	return "badger-db"
+}
+
+// Provides indicates which hook methods this hook provides.
+func (h *Hook) Provides(b byte) bool {
+	return bytes.Contains([]byte{
+		mqtt.OnSessionEstablished,
+		mqtt.OnDisconnect,
+		mqtt.OnSubscribed,
+		mqtt.OnUnsubscribed,
+		mqtt.OnRetainMessage,
+		mqtt.OnWillSent,
+		mqtt.OnQosPublish,
+		mqtt.OnQosComplete,
+		mqtt.OnQosDropped,
+		mqtt.OnSysInfoTick,
+		mqtt.OnClientExpired,
+		mqtt.OnRetainedExpired,
+		mqtt.StoredClients,
+		mqtt.StoredInflightMessages,
+		mqtt.StoredRetainedMessages,
+		mqtt.StoredSubscriptions,
+		mqtt.StoredSysInfo,
+	}, []byte{b})
+}
+
+// GcLoop periodically runs the garbage collection process to reclaim space in the value log files.
+// It uses a ticker to trigger the garbage collection at regular intervals specified by the configuration.
+// Refer to: https://dgraph.io/docs/badger/get-started/#garbage-collection
+func (h *Hook) gcLoop() {
+	for range h.gcTicker.C {
+	again:
+		// Run the garbage collection process with a threshold.
+		// If the process returns nil (success), repeat the process.
+		err := h.db.RunValueLogGC(h.config.GcDiscardRatio)
+		if err == nil {
+			goto again // Retry garbage collection if successful.
+		}
+	}
+}
+
+// Init initializes and connects to the badger instance.
+func (h *Hook) Init(config any) error {
+	if _, ok := config.(*Options); !ok && config != nil {
+		return mqtt.ErrInvalidConfigType
+	}
+
+	if config == nil {
+		h.config = new(Options)
+	} else {
+		h.config = config.(*Options)
+	}
+
+	if len(h.config.Path) == 0 {
+		h.config.Path = defaultDbFile
+	}
+
+	if h.config.GcInterval == 0 {
+		h.config.GcInterval = defaultGcInterval
+	}
+
+	if h.config.GcDiscardRatio <= 0.0 || h.config.GcDiscardRatio >= 1.0 {
+		h.config.GcDiscardRatio = defaultGcDiscardRatio
+	}
+
+	if h.config.Options == nil {
+		defaultOpts := badgerdb.DefaultOptions(h.config.Path)
+		h.config.Options = &defaultOpts
+	}
+	h.config.Options.Logger = h
+
+	var err error
+	h.db, err = badgerdb.Open(*h.config.Options)
+	if err != nil {
+		return err
+	}
+
+	h.gcTicker = time.NewTicker(time.Duration(h.config.GcInterval) * time.Second)
+	go h.gcLoop()
+
+	return nil
+}
+
+// Stop closes the badger instance.
+func (h *Hook) Stop() error {
+	if h.gcTicker != nil {
+		h.gcTicker.Stop()
+	}
+	return h.db.Close()
+}
+
+// OnSessionEstablished adds a client to the store when their session is established.
+func (h *Hook) OnSessionEstablished(cl *mqtt.Client, pk packets.Packet) {
+	h.updateClient(cl)
+}
+
+// OnWillSent is called when a client sends a Will Message and the Will Message is removed from the client record.
+func (h *Hook) OnWillSent(cl *mqtt.Client, pk packets.Packet) {
+	h.updateClient(cl)
+}
+
+// updateClient writes the client data to the store.
+func (h *Hook) updateClient(cl *mqtt.Client) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	props := cl.Properties.Props.Copy(false)
+	in := &storage.Client{
+		ID:              cl.ID,
+		T:               storage.ClientKey,
+		Remote:          cl.Net.Remote,
+		Listener:        cl.Net.Listener,
+		Username:        cl.Properties.Username,
+		Clean:           cl.Properties.Clean,
+		ProtocolVersion: cl.Properties.ProtocolVersion,
+		Properties: storage.ClientProperties{
+			SessionExpiryInterval: props.SessionExpiryInterval,
+			AuthenticationMethod:  props.AuthenticationMethod,
+			AuthenticationData:    props.AuthenticationData,
+			RequestProblemInfo:    props.RequestProblemInfo,
+			RequestResponseInfo:   props.RequestResponseInfo,
+			ReceiveMaximum:        props.ReceiveMaximum,
+			TopicAliasMaximum:     props.TopicAliasMaximum,
+			User:                  props.User,
+			MaximumPacketSize:     props.MaximumPacketSize,
+		},
+		Will: storage.ClientWill(cl.Properties.Will),
+	}
+
+	err := h.setKv(clientKey(cl), in)
+	if err != nil {
+		h.Log.Error("failed to upsert client data", "error", err, "data", in)
+	}
+}
+
+// OnDisconnect removes a client from the store if their session has expired.
+func (h *Hook) OnDisconnect(cl *mqtt.Client, _ error, expire bool) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	h.updateClient(cl)
+
+	if !expire {
+		return
+	}
+
+	if errors.Is(cl.StopCause(), packets.ErrSessionTakenOver) {
+		return
+	}
+
+	_ = h.delKv(clientKey(cl))
+}
+
+// OnSubscribed adds one or more client subscriptions to the store.
+func (h *Hook) OnSubscribed(cl *mqtt.Client, pk packets.Packet, reasonCodes []byte) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	var in *storage.Subscription
+	for i := 0; i < len(pk.Filters); i++ {
+		in = &storage.Subscription{
+			ID:                subscriptionKey(cl, pk.Filters[i].Filter),
+			T:                 storage.SubscriptionKey,
+			Client:            cl.ID,
+			Qos:               reasonCodes[i],
+			Filter:            pk.Filters[i].Filter,
+			Identifier:        pk.Filters[i].Identifier,
+			NoLocal:           pk.Filters[i].NoLocal,
+			RetainHandling:    pk.Filters[i].RetainHandling,
+			RetainAsPublished: pk.Filters[i].RetainAsPublished,
+		}
+
+		_ = h.setKv(in.ID, in)
+	}
+}
+
+// OnUnsubscribed removes one or more client subscriptions from the store.
+func (h *Hook) OnUnsubscribed(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	for i := 0; i < len(pk.Filters); i++ {
+		_ = h.delKv(subscriptionKey(cl, pk.Filters[i].Filter))
+	}
+}
+
+// OnRetainMessage adds a retained message for a topic to the store.
+func (h *Hook) OnRetainMessage(cl *mqtt.Client, pk packets.Packet, r int64) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	if r == -1 {
+		_ = h.delKv(retainedKey(pk.TopicName))
+		return
+	}
+
+	props := pk.Properties.Copy(false)
+	in := &storage.Message{
+		ID:          retainedKey(pk.TopicName),
+		T:           storage.RetainedKey,
+		FixedHeader: pk.FixedHeader,
+		TopicName:   pk.TopicName,
+		Payload:     pk.Payload,
+		Created:     pk.Created,
+		Origin:      pk.Origin,
+		Properties: storage.MessageProperties{
+			PayloadFormat:          props.PayloadFormat,
+			MessageExpiryInterval:  props.MessageExpiryInterval,
+			ContentType:            props.ContentType,
+			ResponseTopic:          props.ResponseTopic,
+			CorrelationData:        props.CorrelationData,
+			SubscriptionIdentifier: props.SubscriptionIdentifier,
+			TopicAlias:             props.TopicAlias,
+			User:                   props.User,
+		},
+	}
+
+	_ = h.setKv(in.ID, in)
+}
+
+// OnQosPublish adds or updates an inflight message in the store.
+func (h *Hook) OnQosPublish(cl *mqtt.Client, pk packets.Packet, sent int64, resends int) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	props := pk.Properties.Copy(false)
+	in := &storage.Message{
+		ID:          inflightKey(cl, pk),
+		T:           storage.InflightKey,
+		Origin:      pk.Origin,
+		PacketID:    pk.PacketID,
+		FixedHeader: pk.FixedHeader,
+		TopicName:   pk.TopicName,
+		Payload:     pk.Payload,
+		Sent:        sent,
+		Created:     pk.Created,
+		Properties: storage.MessageProperties{
+			PayloadFormat:          props.PayloadFormat,
+			MessageExpiryInterval:  props.MessageExpiryInterval,
+			ContentType:            props.ContentType,
+			ResponseTopic:          props.ResponseTopic,
+			CorrelationData:        props.CorrelationData,
+			SubscriptionIdentifier: props.SubscriptionIdentifier,
+			TopicAlias:             props.TopicAlias,
+			User:                   props.User,
+		},
+	}
+
+	_ = h.setKv(in.ID, in)
+}
+
+// OnQosComplete removes a resolved inflight message from the store.
+func (h *Hook) OnQosComplete(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	_ = h.delKv(inflightKey(cl, pk))
+}
+
+// OnQosDropped removes a dropped inflight message from the store.
+func (h *Hook) OnQosDropped(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+	}
+
+	h.OnQosComplete(cl, pk)
+}
+
+// OnSysInfoTick stores the latest system info in the store.
+func (h *Hook) OnSysInfoTick(sys *system.Info) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	in := &storage.SystemInfo{
+		ID:   sysInfoKey(),
+		T:    storage.SysInfoKey,
+		Info: *sys.Clone(),
+	}
+
+	_ = h.setKv(in.ID, in)
+}
+
+// OnRetainedExpired deletes expired retained messages from the store.
+func (h *Hook) OnRetainedExpired(filter string) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	_ = h.delKv(retainedKey(filter))
+}
+
+// OnClientExpired deleted expired clients from the store.
+func (h *Hook) OnClientExpired(cl *mqtt.Client) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	_ = h.delKv(clientKey(cl))
+}
+
+// StoredClients returns all stored clients from the store.
+func (h *Hook) StoredClients() (v []storage.Client, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	err = h.iterKv(storage.ClientKey, func(value []byte) error {
+		obj := storage.Client{}
+		err = obj.UnmarshalBinary(value)
+		if err == nil {
+			v = append(v, obj)
+		}
+		return err
+	})
+	return
+}
+
+// StoredSubscriptions returns all stored subscriptions from the store.
+func (h *Hook) StoredSubscriptions() (v []storage.Subscription, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	v = make([]storage.Subscription, 0)
+	err = h.iterKv(storage.SubscriptionKey, func(value []byte) error {
+		obj := storage.Subscription{}
+		err = obj.UnmarshalBinary(value)
+		if err == nil {
+			v = append(v, obj)
+		}
+		return err
+	})
+	return
+}
+
+// StoredRetainedMessages returns all stored retained messages from the store.
+func (h *Hook) StoredRetainedMessages() (v []storage.Message, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	v = make([]storage.Message, 0)
+	err = h.iterKv(storage.RetainedKey, func(value []byte) error {
+		obj := storage.Message{}
+		err = obj.UnmarshalBinary(value)
+		if err == nil {
+			v = append(v, obj)
+		}
+		return err
+	})
+
+	if err != nil && !errors.Is(err, badgerdb.ErrKeyNotFound) {
+		return
+	}
+	return
+}
+
+// StoredInflightMessages returns all stored inflight messages from the store.
+func (h *Hook) StoredInflightMessages() (v []storage.Message, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	v = make([]storage.Message, 0)
+	err = h.iterKv(storage.InflightKey, func(value []byte) error {
+		obj := storage.Message{}
+		err = obj.UnmarshalBinary(value)
+		if err == nil {
+			v = append(v, obj)
+		}
+		return err
+	})
+	return
+}
+
+// StoredSysInfo returns the system info from the store.
+func (h *Hook) StoredSysInfo() (v storage.SystemInfo, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	err = h.getKv(storage.SysInfoKey, &v)
+	if err != nil && !errors.Is(err, badgerdb.ErrKeyNotFound) {
+		return
+	}
+	return v, nil
+}
+
+// Errorf satisfies the badger interface for an error logger.
+func (h *Hook) Errorf(m string, v ...any) {
+	h.Log.Error(fmt.Sprintf(strings.ToLower(strings.Trim(m, "\n")), v...), "v", v)
+
+}
+
+// Warningf satisfies the badger interface for a warning logger.
+func (h *Hook) Warningf(m string, v ...any) {
+	h.Log.Warn(fmt.Sprintf(strings.ToLower(strings.Trim(m, "\n")), v...), "v", v)
+}
+
+// Infof satisfies the badger interface for an info logger.
+func (h *Hook) Infof(m string, v ...any) {
+	h.Log.Info(fmt.Sprintf(strings.ToLower(strings.Trim(m, "\n")), v...), "v", v)
+}
+
+// Debugf satisfies the badger interface for a debug logger.
+func (h *Hook) Debugf(m string, v ...any) {
+	h.Log.Debug(fmt.Sprintf(strings.ToLower(strings.Trim(m, "\n")), v...), "v", v)
+}
+
+// setKv stores a key-value pair in the database.
+func (h *Hook) setKv(k string, v storage.Serializable) error {
+	err := h.db.Update(func(txn *badgerdb.Txn) error {
+		data, _ := v.MarshalBinary()
+		return txn.Set([]byte(k), data)
+	})
+	if err != nil {
+		h.Log.Error("failed to upsert data", "error", err, "key", k)
+	}
+	return err
+}
+
+// delKv deletes a key-value pair from the database.
+func (h *Hook) delKv(k string) error {
+	err := h.db.Update(func(txn *badgerdb.Txn) error {
+		return txn.Delete([]byte(k))
+	})
+
+	if err != nil {
+		h.Log.Error("failed to delete data", "error", err, "key", k)
+	}
+	return err
+}
+
+// getKv retrieves the value associated with a key from the database.
+func (h *Hook) getKv(k string, v storage.Serializable) error {
+	return h.db.View(func(txn *badgerdb.Txn) error {
+		item, err := txn.Get([]byte(k))
+		if err != nil {
+			return err
+		}
+		value, err := item.ValueCopy(nil)
+		if err != nil {
+			return err
+		}
+		return v.UnmarshalBinary(value)
+	})
+}
+
+// iterKv iterates over key-value pairs with keys having the specified prefix in the database.
+func (h *Hook) iterKv(prefix string, visit func([]byte) error) error {
+	err := h.db.View(func(txn *badgerdb.Txn) error {
+		iterator := txn.NewIterator(badgerdb.DefaultIteratorOptions)
+		defer iterator.Close()
+
+		for iterator.Seek([]byte(prefix)); iterator.ValidForPrefix([]byte(prefix)); iterator.Next() {
+			item := iterator.Item()
+			value, err := item.ValueCopy(nil)
+
+			if err != nil {
+				return err
+			}
+
+			if err := visit(value); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		h.Log.Error("failed to find data", "error", err, "prefix", prefix)
+	}
+	return err
+}

hooks/storage/badger/badger_test.go

@@ -0,0 +1,809 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: mochi-co, werbenhu
+
+package badger
+
+import (
+	"errors"
+	"log/slog"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	badgerdb "github.com/dgraph-io/badger/v4"
+	"testmqtt/hooks/storage"
+	"testmqtt/mqtt"
+	"testmqtt/packets"
+	"testmqtt/system"
+
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	logger = slog.New(slog.NewTextHandler(os.Stdout, nil))
+
+	client = &mqtt.Client{
+		ID: "test",
+		Net: mqtt.ClientConnection{
+			Remote:   "test.addr",
+			Listener: "listener",
+		},
+		Properties: mqtt.ClientProperties{
+			Username: []byte("username"),
+			Clean:    false,
+		},
+	}
+
+	pkf = packets.Packet{Filters: packets.Subscriptions{{Filter: "a/b/c"}}}
+)
+
+func teardown(t *testing.T, path string, h *Hook) {
+	_ = h.Stop()
+	_ = h.db.Close()
+	err := os.RemoveAll("./" + strings.Replace(path, "..", "", -1))
+	require.NoError(t, err)
+}
+
+func TestSetGetDelKv(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Init(nil)
+	defer teardown(t, h.config.Path, h)
+
+	key := "testKey"
+	value := &storage.Client{ID: "cl1"}
+	err := h.setKv(key, value)
+	require.NoError(t, err)
+
+	var client storage.Client
+	err = h.getKv(key, &client)
+	require.NoError(t, err)
+	require.Equal(t, "cl1", client.ID)
+
+	err = h.delKv(key)
+	require.NoError(t, err)
+
+	err = h.getKv(key, &client)
+	require.ErrorIs(t, badgerdb.ErrKeyNotFound, err)
+}
+
+func TestClientKey(t *testing.T) {
+	k := clientKey(&mqtt.Client{ID: "cl1"})
+	require.Equal(t, storage.ClientKey+"_cl1", k)
+}
+
+func TestSubscriptionKey(t *testing.T) {
+	k := subscriptionKey(&mqtt.Client{ID: "cl1"}, "a/b/c")
+	require.Equal(t, storage.SubscriptionKey+"_cl1:a/b/c", k)
+}
+
+func TestRetainedKey(t *testing.T) {
+	k := retainedKey("a/b/c")
+	require.Equal(t, storage.RetainedKey+"_a/b/c", k)
+}
+
+func TestInflightKey(t *testing.T) {
+	k := inflightKey(&mqtt.Client{ID: "cl1"}, packets.Packet{PacketID: 1})
+	require.Equal(t, storage.InflightKey+"_cl1:1", k)
+}
+
+func TestSysInfoKey(t *testing.T) {
+	require.Equal(t, storage.SysInfoKey, sysInfoKey())
+}
+
+func TestID(t *testing.T) {
+	h := new(Hook)
+	require.Equal(t, "badger-db", h.ID())
+}
+
+func TestProvides(t *testing.T) {
+	h := new(Hook)
+	require.True(t, h.Provides(mqtt.OnSessionEstablished))
+	require.True(t, h.Provides(mqtt.OnDisconnect))
+	require.True(t, h.Provides(mqtt.OnSubscribed))
+	require.True(t, h.Provides(mqtt.OnUnsubscribed))
+	require.True(t, h.Provides(mqtt.OnRetainMessage))
+	require.True(t, h.Provides(mqtt.OnQosPublish))
+	require.True(t, h.Provides(mqtt.OnQosComplete))
+	require.True(t, h.Provides(mqtt.OnQosDropped))
+	require.True(t, h.Provides(mqtt.OnSysInfoTick))
+	require.True(t, h.Provides(mqtt.StoredClients))
+	require.True(t, h.Provides(mqtt.StoredInflightMessages))
+	require.True(t, h.Provides(mqtt.StoredRetainedMessages))
+	require.True(t, h.Provides(mqtt.StoredSubscriptions))
+	require.True(t, h.Provides(mqtt.StoredSysInfo))
+	require.False(t, h.Provides(mqtt.OnACLCheck))
+	require.False(t, h.Provides(mqtt.OnConnectAuthenticate))
+}
+
+func TestInitBadConfig(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(map[string]any{})
+	require.Error(t, err)
+}
+
+func TestInitBadOption(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(&Options{
+		Options: &badgerdb.Options{
+			NumCompactors: 1,
+		},
+	})
+	// Cannot have 1 compactor. Need at least 2
+	require.Error(t, err)
+}
+
+func TestInitUseDefaults(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	require.Equal(t, defaultDbFile, h.config.Path)
+}
+
+func TestOnSessionEstablishedThenOnDisconnect(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	h.OnSessionEstablished(client, packets.Packet{})
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey(client), r)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.ID)
+	require.Equal(t, client.Properties.Username, r.Username)
+	require.Equal(t, client.Properties.Clean, r.Clean)
+	require.Equal(t, client.Net.Remote, r.Remote)
+	require.Equal(t, client.Net.Listener, r.Listener)
+	require.NotSame(t, client, r)
+
+	h.OnDisconnect(client, nil, false)
+	r2 := new(storage.Client)
+	err = h.getKv(clientKey(client), r2)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.ID)
+
+	h.OnDisconnect(client, nil, true)
+	r3 := new(storage.Client)
+	err = h.getKv(clientKey(client), r3)
+	require.Error(t, err)
+	require.ErrorIs(t, badgerdb.ErrKeyNotFound, err)
+	require.Empty(t, r3.ID)
+}
+
+func TestOnClientExpired(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	cl := &mqtt.Client{ID: "cl1"}
+	clientKey := clientKey(cl)
+
+	err = h.setKv(clientKey, &storage.Client{ID: cl.ID})
+	require.NoError(t, err)
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey, r)
+
+	require.NoError(t, err)
+	require.Equal(t, cl.ID, r.ID)
+
+	h.OnClientExpired(cl)
+	err = h.getKv(clientKey, r)
+	require.Error(t, err)
+	require.ErrorIs(t, badgerdb.ErrKeyNotFound, err)
+}
+
+func TestOnClientExpiredNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnClientExpired(client)
+}
+
+func TestOnClientExpiredClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnClientExpired(client)
+}
+
+func TestOnSessionEstablishedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSessionEstablished(client, packets.Packet{})
+}
+
+func TestOnSessionEstablishedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSessionEstablished(client, packets.Packet{})
+}
+
+func TestOnWillSent(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	c1 := client
+	c1.Properties.Will.Flag = 1
+	h.OnWillSent(c1, packets.Packet{})
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey(client), r)
+	require.NoError(t, err)
+
+	require.Equal(t, uint32(1), r.Will.Flag)
+	require.NotSame(t, client, r)
+}
+
+func TestOnDisconnectNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnDisconnect(client, nil, false)
+}
+
+func TestOnDisconnectClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnDisconnect(client, nil, false)
+}
+
+func TestOnDisconnectSessionTakenOver(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+
+	testClient := &mqtt.Client{
+		ID: "test",
+		Net: mqtt.ClientConnection{
+			Remote:   "test.addr",
+			Listener: "listener",
+		},
+		Properties: mqtt.ClientProperties{
+			Username: []byte("username"),
+			Clean:    false,
+		},
+	}
+
+	testClient.Stop(packets.ErrSessionTakenOver)
+	teardown(t, h.config.Path, h)
+	h.OnDisconnect(testClient, nil, true)
+}
+
+func TestOnSubscribedThenOnUnsubscribed(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	h.OnSubscribed(client, pkf, []byte{0})
+	r := new(storage.Subscription)
+
+	err = h.getKv(subscriptionKey(client, pkf.Filters[0].Filter), r)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.Client)
+	require.Equal(t, pkf.Filters[0].Filter, r.Filter)
+	require.Equal(t, byte(0), r.Qos)
+
+	h.OnUnsubscribed(client, pkf)
+	err = h.getKv(subscriptionKey(client, pkf.Filters[0].Filter), r)
+	require.Error(t, err)
+	require.Equal(t, badgerdb.ErrKeyNotFound, err)
+}
+
+func TestOnSubscribedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSubscribed(client, pkf, []byte{0})
+}
+
+func TestOnSubscribedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSubscribed(client, pkf, []byte{0})
+}
+
+func TestOnUnsubscribedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnUnsubscribed(client, pkf)
+}
+
+func TestOnUnsubscribedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnUnsubscribed(client, pkf)
+}
+
+func TestOnRetainMessageThenUnset(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	pk := packets.Packet{
+		FixedHeader: packets.FixedHeader{
+			Retain: true,
+		},
+		Payload:   []byte("hello"),
+		TopicName: "a/b/c",
+	}
+
+	h.OnRetainMessage(client, pk, 1)
+
+	r := new(storage.Message)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.NoError(t, err)
+	require.Equal(t, pk.TopicName, r.TopicName)
+	require.Equal(t, pk.Payload, r.Payload)
+
+	h.OnRetainMessage(client, pk, -1)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, badgerdb.ErrKeyNotFound)
+
+	// coverage: delete deleted
+	h.OnRetainMessage(client, pk, -1)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, badgerdb.ErrKeyNotFound)
+}
+
+func TestOnRetainedExpired(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	m := &storage.Message{
+		ID:        retainedKey("a/b/c"),
+		T:         storage.RetainedKey,
+		TopicName: "a/b/c",
+	}
+
+	err = h.setKv(m.ID, m)
+	require.NoError(t, err)
+
+	r := new(storage.Message)
+	err = h.getKv(m.ID, r)
+	require.NoError(t, err)
+	require.Equal(t, m.TopicName, r.TopicName)
+
+	h.OnRetainedExpired(m.TopicName)
+	err = h.getKv(m.ID, r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, badgerdb.ErrKeyNotFound)
+}
+
+func TestOnRetainExpiredNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnRetainedExpired("a/b/c")
+}
+
+func TestOnRetainExpiredClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnRetainedExpired("a/b/c")
+}
+
+func TestOnRetainMessageNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnRetainMessage(client, packets.Packet{}, 0)
+}
+
+func TestOnRetainMessageClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnRetainMessage(client, packets.Packet{}, 0)
+}
+
+func TestOnQosPublishThenQOSComplete(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	pk := packets.Packet{
+		FixedHeader: packets.FixedHeader{
+			Retain: true,
+			Qos:    2,
+		},
+		Payload:   []byte("hello"),
+		TopicName: "a/b/c",
+	}
+
+	h.OnQosPublish(client, pk, time.Now().Unix(), 0)
+
+	r := new(storage.Message)
+	err = h.getKv(inflightKey(client, pk), r)
+	require.NoError(t, err)
+	require.Equal(t, pk.TopicName, r.TopicName)
+	require.Equal(t, pk.Payload, r.Payload)
+
+	// ensure dates are properly saved
+	require.True(t, r.Sent > 0)
+	require.True(t, time.Now().Unix()-1 < r.Sent)
+
+	// OnQosDropped is a passthrough to OnQosComplete here
+	h.OnQosDropped(client, pk)
+	err = h.getKv(inflightKey(client, pk), r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, badgerdb.ErrKeyNotFound)
+}
+
+func TestOnQosPublishNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosPublish(client, packets.Packet{}, time.Now().Unix(), 0)
+}
+
+func TestOnQosPublishClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnQosPublish(client, packets.Packet{}, time.Now().Unix(), 0)
+}
+
+func TestOnQosCompleteNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosComplete(client, packets.Packet{})
+}
+
+func TestOnQosCompleteClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnQosComplete(client, packets.Packet{})
+}
+
+func TestOnQosDroppedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosDropped(client, packets.Packet{})
+}
+
+func TestOnSysInfoTick(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	info := &system.Info{
+		Version:       "2.0.0",
+		BytesReceived: 100,
+	}
+
+	h.OnSysInfoTick(info)
+
+	r := new(storage.SystemInfo)
+	err = h.getKv(storage.SysInfoKey, r)
+	require.NoError(t, err)
+	require.Equal(t, info.Version, r.Version)
+	require.Equal(t, info.BytesReceived, r.BytesReceived)
+	require.NotSame(t, info, r)
+}
+
+func TestOnSysInfoTickNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSysInfoTick(new(system.Info))
+}
+
+func TestOnSysInfoTickClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSysInfoTick(new(system.Info))
+}
+
+func TestStoredClients(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with clients
+	err = h.setKv(storage.ClientKey+"_cl1", &storage.Client{ID: "cl1", T: storage.ClientKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.ClientKey+"_cl2", &storage.Client{ID: "cl2", T: storage.ClientKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.ClientKey+"_cl3", &storage.Client{ID: "cl3", T: storage.ClientKey})
+	require.NoError(t, err)
+
+	r, err := h.StoredClients()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "cl1", r[0].ID)
+	require.Equal(t, "cl2", r[1].ID)
+	require.Equal(t, "cl3", r[2].ID)
+}
+
+func TestStoredClientsNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredClients()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredSubscriptions(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with subscriptions
+	err = h.setKv(storage.SubscriptionKey+"_sub1", &storage.Subscription{ID: "sub1", T: storage.SubscriptionKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.SubscriptionKey+"_sub2", &storage.Subscription{ID: "sub2", T: storage.SubscriptionKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.SubscriptionKey+"_sub3", &storage.Subscription{ID: "sub3", T: storage.SubscriptionKey})
+	require.NoError(t, err)
+
+	r, err := h.StoredSubscriptions()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "sub1", r[0].ID)
+	require.Equal(t, "sub2", r[1].ID)
+	require.Equal(t, "sub3", r[2].ID)
+}
+
+func TestStoredSubscriptionsNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredSubscriptions()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredRetainedMessages(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with messages
+	err = h.setKv(storage.RetainedKey+"_m1", &storage.Message{ID: "m1", T: storage.RetainedKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_m2", &storage.Message{ID: "m2", T: storage.RetainedKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_m3", &storage.Message{ID: "m3", T: storage.RetainedKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_i3", &storage.Message{ID: "i3", T: storage.InflightKey})
+	require.NoError(t, err)
+
+	r, err := h.StoredRetainedMessages()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "m1", r[0].ID)
+	require.Equal(t, "m2", r[1].ID)
+	require.Equal(t, "m3", r[2].ID)
+}
+
+func TestStoredRetainedMessagesNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredRetainedMessages()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredInflightMessages(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with messages
+	err = h.setKv(storage.InflightKey+"_i1", &storage.Message{ID: "i1", T: storage.InflightKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_i2", &storage.Message{ID: "i2", T: storage.InflightKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_i3", &storage.Message{ID: "i3", T: storage.InflightKey})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_m1", &storage.Message{ID: "m1", T: storage.RetainedKey})
+	require.NoError(t, err)
+
+	r, err := h.StoredInflightMessages()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "i1", r[0].ID)
+	require.Equal(t, "i2", r[1].ID)
+	require.Equal(t, "i3", r[2].ID)
+}
+
+func TestStoredInflightMessagesNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredInflightMessages()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredSysInfo(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with messages
+	err = h.setKv(storage.SysInfoKey, &storage.SystemInfo{
+		ID: storage.SysInfoKey,
+		Info: system.Info{
+			Version: "2.0.0",
+		},
+		T: storage.SysInfoKey,
+	})
+	require.NoError(t, err)
+
+	r, err := h.StoredSysInfo()
+	require.NoError(t, err)
+	require.Equal(t, "2.0.0", r.Info.Version)
+}
+
+func TestStoredSysInfoNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredSysInfo()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestErrorf(t *testing.T) {
+	// coverage: one day check log hook
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Errorf("test", 1, 2, 3)
+}
+
+func TestWarningf(t *testing.T) {
+	// coverage: one day check log hook
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Warningf("test", 1, 2, 3)
+}
+
+func TestInfof(t *testing.T) {
+	// coverage: one day check log hook
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Infof("test", 1, 2, 3)
+}
+
+func TestDebugf(t *testing.T) {
+	// coverage: one day check log hook
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Debugf("test", 1, 2, 3)
+}
+
+func TestGcLoop(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	opts := badgerdb.DefaultOptions(defaultDbFile)
+	opts.ValueLogFileSize = 1 << 20
+	h.Init(&Options{
+		GcInterval: 2, // Set the interval for garbage collection.
+		Options:    &opts,
+	})
+	defer teardown(t, defaultDbFile, h)
+	h.OnSessionEstablished(client, packets.Packet{})
+	h.OnDisconnect(client, nil, true)
+	time.Sleep(3 * time.Second)
+}
+
+func TestGetSetDelKv(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	defer teardown(t, h.config.Path, h)
+	require.NoError(t, err)
+
+	err = h.setKv("testKey", &storage.Client{ID: "testId"})
+	require.NoError(t, err)
+
+	var obj storage.Client
+	err = h.getKv("testKey", &obj)
+	require.NoError(t, err)
+
+	err = h.delKv("testKey")
+	require.NoError(t, err)
+
+	err = h.getKv("testKey", &obj)
+	require.Error(t, err)
+	require.ErrorIs(t, badgerdb.ErrKeyNotFound, err)
+}
+
+func TestIterKv(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(nil)
+	defer teardown(t, h.config.Path, h)
+	require.NoError(t, err)
+
+	h.setKv("prefix_a_1", &storage.Client{ID: "1"})
+	h.setKv("prefix_a_2", &storage.Client{ID: "2"})
+	h.setKv("prefix_b_2", &storage.Client{ID: "3"})
+
+	var clients []storage.Client
+	err = h.iterKv("prefix_a", func(data []byte) error {
+		var item storage.Client
+		item.UnmarshalBinary(data)
+		clients = append(clients, item)
+		return nil
+	})
+	require.Equal(t, 2, len(clients))
+	require.NoError(t, err)
+
+	visitErr := errors.New("iter visit error")
+	err = h.iterKv("prefix_b", func(data []byte) error {
+		return visitErr
+	})
+	require.ErrorIs(t, visitErr, err)
+}

hooks/storage/bolt/bolt.go

@@ -0,0 +1,525 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: mochi-co, werbenhu
+
+// Package bolt is provided for historical compatibility and may not be actively updated, you should use the badger hook instead.
+package bolt
+
+import (
+	"bytes"
+	"errors"
+	"time"
+
+	"testmqtt/hooks/storage"
+	"testmqtt/mqtt"
+	"testmqtt/packets"
+	"testmqtt/system"
+
+	"go.etcd.io/bbolt"
+)
+
+var (
+	ErrBucketNotFound = errors.New("bucket not found")
+	ErrKeyNotFound    = errors.New("key not found")
+)
+
+const (
+	// defaultDbFile is the default file path for the boltdb file.
+	defaultDbFile = ".bolt"
+
+	// defaultTimeout is the default time to hold a connection to the file.
+	defaultTimeout = 250 * time.Millisecond
+
+	defaultBucket = "mochi"
+)
+
+// clientKey returns a primary key for a client.
+func clientKey(cl *mqtt.Client) string {
+	return storage.ClientKey + "_" + cl.ID
+}
+
+// subscriptionKey returns a primary key for a subscription.
+func subscriptionKey(cl *mqtt.Client, filter string) string {
+	return storage.SubscriptionKey + "_" + cl.ID + ":" + filter
+}
+
+// retainedKey returns a primary key for a retained message.
+func retainedKey(topic string) string {
+	return storage.RetainedKey + "_" + topic
+}
+
+// inflightKey returns a primary key for an inflight message.
+func inflightKey(cl *mqtt.Client, pk packets.Packet) string {
+	return storage.InflightKey + "_" + cl.ID + ":" + pk.FormatID()
+}
+
+// sysInfoKey returns a primary key for system info.
+func sysInfoKey() string {
+	return storage.SysInfoKey
+}
+
+// Options contains configuration settings for the bolt instance.
+type Options struct {
+	Options *bbolt.Options
+	Bucket  string `yaml:"bucket" json:"bucket"`
+	Path    string `yaml:"path" json:"path"`
+}
+
+// Hook is a persistent storage hook based using boltdb file store as a backend.
+type Hook struct {
+	mqtt.HookBase
+	config *Options  // options for configuring the boltdb instance.
+	db     *bbolt.DB // the boltdb instance.
+}
+
+// ID returns the id of the hook.
+func (h *Hook) ID() string {
+	return "bolt-db"
+}
+
+// Provides indicates which hook methods this hook provides.
+func (h *Hook) Provides(b byte) bool {
+	return bytes.Contains([]byte{
+		mqtt.OnSessionEstablished,
+		mqtt.OnDisconnect,
+		mqtt.OnSubscribed,
+		mqtt.OnUnsubscribed,
+		mqtt.OnRetainMessage,
+		mqtt.OnWillSent,
+		mqtt.OnQosPublish,
+		mqtt.OnQosComplete,
+		mqtt.OnQosDropped,
+		mqtt.OnSysInfoTick,
+		mqtt.OnClientExpired,
+		mqtt.OnRetainedExpired,
+		mqtt.StoredClients,
+		mqtt.StoredInflightMessages,
+		mqtt.StoredRetainedMessages,
+		mqtt.StoredSubscriptions,
+		mqtt.StoredSysInfo,
+	}, []byte{b})
+}
+
+// Init initializes and connects to the boltdb instance.
+func (h *Hook) Init(config any) error {
+	if _, ok := config.(*Options); !ok && config != nil {
+		return mqtt.ErrInvalidConfigType
+	}
+
+	if config == nil {
+		config = new(Options)
+	}
+
+	h.config = config.(*Options)
+	if h.config.Options == nil {
+		h.config.Options = &bbolt.Options{
+			Timeout: defaultTimeout,
+		}
+	}
+	if len(h.config.Path) == 0 {
+		h.config.Path = defaultDbFile
+	}
+
+	if len(h.config.Bucket) == 0 {
+		h.config.Bucket = defaultBucket
+	}
+
+	var err error
+	h.db, err = bbolt.Open(h.config.Path, 0600, h.config.Options)
+	if err != nil {
+		return err
+	}
+
+	err = h.db.Update(func(tx *bbolt.Tx) error {
+		_, err := tx.CreateBucketIfNotExists([]byte(h.config.Bucket))
+		return err
+	})
+	return err
+}
+
+// Stop closes the boltdb instance.
+func (h *Hook) Stop() error {
+	err := h.db.Close()
+	h.db = nil
+	return err
+}
+
+// OnSessionEstablished adds a client to the store when their session is established.
+func (h *Hook) OnSessionEstablished(cl *mqtt.Client, pk packets.Packet) {
+	h.updateClient(cl)
+}
+
+// OnWillSent is called when a client sends a Will Message and the Will Message is removed from the client record.
+func (h *Hook) OnWillSent(cl *mqtt.Client, pk packets.Packet) {
+	h.updateClient(cl)
+}
+
+// updateClient writes the client data to the store.
+func (h *Hook) updateClient(cl *mqtt.Client) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	props := cl.Properties.Props.Copy(false)
+	in := &storage.Client{
+		ID:              cl.ID,
+		T:               storage.ClientKey,
+		Remote:          cl.Net.Remote,
+		Listener:        cl.Net.Listener,
+		Username:        cl.Properties.Username,
+		Clean:           cl.Properties.Clean,
+		ProtocolVersion: cl.Properties.ProtocolVersion,
+		Properties: storage.ClientProperties{
+			SessionExpiryInterval: props.SessionExpiryInterval,
+			AuthenticationMethod:  props.AuthenticationMethod,
+			AuthenticationData:    props.AuthenticationData,
+			RequestProblemInfo:    props.RequestProblemInfo,
+			RequestResponseInfo:   props.RequestResponseInfo,
+			ReceiveMaximum:        props.ReceiveMaximum,
+			TopicAliasMaximum:     props.TopicAliasMaximum,
+			User:                  props.User,
+			MaximumPacketSize:     props.MaximumPacketSize,
+		},
+		Will: storage.ClientWill(cl.Properties.Will),
+	}
+
+	_ = h.setKv(clientKey(cl), in)
+}
+
+// OnDisconnect removes a client from the store if they were using a clean session.
+func (h *Hook) OnDisconnect(cl *mqtt.Client, _ error, expire bool) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	if !expire {
+		return
+	}
+
+	if cl.StopCause() == packets.ErrSessionTakenOver {
+		return
+	}
+
+	_ = h.delKv(clientKey(cl))
+}
+
+// OnSubscribed adds one or more client subscriptions to the store.
+func (h *Hook) OnSubscribed(cl *mqtt.Client, pk packets.Packet, reasonCodes []byte) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	var in *storage.Subscription
+	for i := 0; i < len(pk.Filters); i++ {
+		in = &storage.Subscription{
+			ID:                subscriptionKey(cl, pk.Filters[i].Filter),
+			T:                 storage.SubscriptionKey,
+			Client:            cl.ID,
+			Qos:               reasonCodes[i],
+			Filter:            pk.Filters[i].Filter,
+			Identifier:        pk.Filters[i].Identifier,
+			NoLocal:           pk.Filters[i].NoLocal,
+			RetainHandling:    pk.Filters[i].RetainHandling,
+			RetainAsPublished: pk.Filters[i].RetainAsPublished,
+		}
+		_ = h.setKv(in.ID, in)
+	}
+}
+
+// OnUnsubscribed removes one or more client subscriptions from the store.
+func (h *Hook) OnUnsubscribed(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	for i := 0; i < len(pk.Filters); i++ {
+		_ = h.delKv(subscriptionKey(cl, pk.Filters[i].Filter))
+	}
+}
+
+// OnRetainMessage adds a retained message for a topic to the store.
+func (h *Hook) OnRetainMessage(cl *mqtt.Client, pk packets.Packet, r int64) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	if r == -1 {
+		_ = h.delKv(retainedKey(pk.TopicName))
+		return
+	}
+
+	props := pk.Properties.Copy(false)
+	in := &storage.Message{
+		ID:          retainedKey(pk.TopicName),
+		T:           storage.RetainedKey,
+		FixedHeader: pk.FixedHeader,
+		TopicName:   pk.TopicName,
+		Payload:     pk.Payload,
+		Created:     pk.Created,
+		Origin:      pk.Origin,
+		Properties: storage.MessageProperties{
+			PayloadFormat:          props.PayloadFormat,
+			MessageExpiryInterval:  props.MessageExpiryInterval,
+			ContentType:            props.ContentType,
+			ResponseTopic:          props.ResponseTopic,
+			CorrelationData:        props.CorrelationData,
+			SubscriptionIdentifier: props.SubscriptionIdentifier,
+			TopicAlias:             props.TopicAlias,
+			User:                   props.User,
+		},
+	}
+
+	_ = h.setKv(in.ID, in)
+}
+
+// OnQosPublish adds or updates an inflight message in the store.
+func (h *Hook) OnQosPublish(cl *mqtt.Client, pk packets.Packet, sent int64, resends int) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	props := pk.Properties.Copy(false)
+	in := &storage.Message{
+		ID:          inflightKey(cl, pk),
+		T:           storage.InflightKey,
+		Origin:      pk.Origin,
+		FixedHeader: pk.FixedHeader,
+		TopicName:   pk.TopicName,
+		Payload:     pk.Payload,
+		Sent:        sent,
+		Created:     pk.Created,
+		Properties: storage.MessageProperties{
+			PayloadFormat:          props.PayloadFormat,
+			MessageExpiryInterval:  props.MessageExpiryInterval,
+			ContentType:            props.ContentType,
+			ResponseTopic:          props.ResponseTopic,
+			CorrelationData:        props.CorrelationData,
+			SubscriptionIdentifier: props.SubscriptionIdentifier,
+			TopicAlias:             props.TopicAlias,
+			User:                   props.User,
+		},
+	}
+
+	_ = h.setKv(in.ID, in)
+}
+
+// OnQosComplete removes a resolved inflight message from the store.
+func (h *Hook) OnQosComplete(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	_ = h.delKv(inflightKey(cl, pk))
+}
+
+// OnQosDropped removes a dropped inflight message from the store.
+func (h *Hook) OnQosDropped(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+	}
+
+	h.OnQosComplete(cl, pk)
+}
+
+// OnSysInfoTick stores the latest system info in the store.
+func (h *Hook) OnSysInfoTick(sys *system.Info) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	in := &storage.SystemInfo{
+		ID:   sysInfoKey(),
+		T:    storage.SysInfoKey,
+		Info: *sys,
+	}
+
+	_ = h.setKv(in.ID, in)
+}
+
+// OnRetainedExpired deletes expired retained messages from the store.
+func (h *Hook) OnRetainedExpired(filter string) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+	_ = h.delKv(retainedKey(filter))
+}
+
+// OnClientExpired deleted expired clients from the store.
+func (h *Hook) OnClientExpired(cl *mqtt.Client) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+	_ = h.delKv(clientKey(cl))
+}
+
+// StoredClients returns all stored clients from the store.
+func (h *Hook) StoredClients() (v []storage.Client, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return v, storage.ErrDBFileNotOpen
+	}
+
+	err = h.iterKv(storage.ClientKey, func(value []byte) error {
+		obj := storage.Client{}
+		err = obj.UnmarshalBinary(value)
+		if err == nil {
+			v = append(v, obj)
+		}
+		return err
+	})
+	return v, nil
+}
+
+// StoredSubscriptions returns all stored subscriptions from the store.
+func (h *Hook) StoredSubscriptions() (v []storage.Subscription, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return v, storage.ErrDBFileNotOpen
+	}
+
+	v = make([]storage.Subscription, 0)
+	err = h.iterKv(storage.SubscriptionKey, func(value []byte) error {
+		obj := storage.Subscription{}
+		err = obj.UnmarshalBinary(value)
+		if err == nil {
+			v = append(v, obj)
+		}
+		return err
+	})
+	return
+}
+
+// StoredRetainedMessages returns all stored retained messages from the store.
+func (h *Hook) StoredRetainedMessages() (v []storage.Message, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return v, storage.ErrDBFileNotOpen
+	}
+
+	v = make([]storage.Message, 0)
+	err = h.iterKv(storage.RetainedKey, func(value []byte) error {
+		obj := storage.Message{}
+		err = obj.UnmarshalBinary(value)
+		if err == nil {
+			v = append(v, obj)
+		}
+		return err
+	})
+	return
+}
+
+// StoredInflightMessages returns all stored inflight messages from the store.
+func (h *Hook) StoredInflightMessages() (v []storage.Message, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return v, storage.ErrDBFileNotOpen
+	}
+
+	v = make([]storage.Message, 0)
+	err = h.iterKv(storage.InflightKey, func(value []byte) error {
+		obj := storage.Message{}
+		err = obj.UnmarshalBinary(value)
+		if err == nil {
+			v = append(v, obj)
+		}
+		return err
+	})
+	return
+}
+
+// StoredSysInfo returns the system info from the store.
+func (h *Hook) StoredSysInfo() (v storage.SystemInfo, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return v, storage.ErrDBFileNotOpen
+	}
+
+	err = h.getKv(storage.SysInfoKey, &v)
+	if err != nil && !errors.Is(err, ErrKeyNotFound) {
+		return
+	}
+
+	return v, nil
+}
+
+// setKv stores a key-value pair in the database.
+func (h *Hook) setKv(k string, v storage.Serializable) error {
+	err := h.db.Update(func(tx *bbolt.Tx) error {
+
+		bucket := tx.Bucket([]byte(h.config.Bucket))
+		data, _ := v.MarshalBinary()
+		err := bucket.Put([]byte(k), data)
+		if err != nil {
+			return err
+		}
+		return nil
+	})
+	if err != nil {
+		h.Log.Error("failed to upsert data", "error", err, "key", k)
+	}
+	return err
+}
+
+// delKv deletes a key-value pair from the database.
+func (h *Hook) delKv(k string) error {
+	err := h.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket([]byte(h.config.Bucket))
+		err := bucket.Delete([]byte(k))
+		if err != nil {
+			return err
+		}
+		return nil
+	})
+	if err != nil {
+		h.Log.Error("failed to delete data", "error", err, "key", k)
+	}
+	return err
+}
+
+// getKv retrieves the value associated with a key from the database.
+func (h *Hook) getKv(k string, v storage.Serializable) error {
+	err := h.db.View(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket([]byte(h.config.Bucket))
+
+		value := bucket.Get([]byte(k))
+		if value == nil {
+			return ErrKeyNotFound
+		}
+
+		return v.UnmarshalBinary(value)
+	})
+	if err != nil {
+		h.Log.Error("failed to get data", "error", err, "key", k)
+	}
+	return err
+}
+
+// iterKv iterates over key-value pairs with keys having the specified prefix in the database.
+func (h *Hook) iterKv(prefix string, visit func([]byte) error) error {
+	err := h.db.View(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket([]byte(h.config.Bucket))
+
+		c := bucket.Cursor()
+		for k, v := c.Seek([]byte(prefix)); k != nil && string(k[:len(prefix)]) == prefix; k, v = c.Next() {
+			if err := visit(v); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+
+	if err != nil {
+		h.Log.Error("failed to iter data", "error", err, "prefix", prefix)
+	}
+	return err
+}

hooks/storage/bolt/bolt_test.go

@@ -0,0 +1,791 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: mochi-co, werbenhu
+
+package bolt
+
+import (
+	"errors"
+	"log/slog"
+	"os"
+	"testing"
+	"time"
+
+	"testmqtt/hooks/storage"
+	"testmqtt/mqtt"
+	"testmqtt/packets"
+	"testmqtt/system"
+
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	logger = slog.New(slog.NewTextHandler(os.Stdout, nil))
+
+	client = &mqtt.Client{
+		ID: "test",
+		Net: mqtt.ClientConnection{
+			Remote:   "test.addr",
+			Listener: "listener",
+		},
+		Properties: mqtt.ClientProperties{
+			Username: []byte("username"),
+			Clean:    false,
+		},
+	}
+
+	pkf = packets.Packet{Filters: packets.Subscriptions{{Filter: "a/b/c"}}}
+)
+
+func teardown(t *testing.T, path string, h *Hook) {
+	_ = h.Stop()
+	err := os.Remove(path)
+	require.NoError(t, err)
+}
+
+func TestClientKey(t *testing.T) {
+	k := clientKey(&mqtt.Client{ID: "cl1"})
+	require.Equal(t, "CL_cl1", k)
+}
+
+func TestSubscriptionKey(t *testing.T) {
+	k := subscriptionKey(&mqtt.Client{ID: "cl1"}, "a/b/c")
+	require.Equal(t, storage.SubscriptionKey+"_cl1:a/b/c", k)
+}
+
+func TestRetainedKey(t *testing.T) {
+	k := retainedKey("a/b/c")
+	require.Equal(t, storage.RetainedKey+"_a/b/c", k)
+}
+
+func TestInflightKey(t *testing.T) {
+	k := inflightKey(&mqtt.Client{ID: "cl1"}, packets.Packet{PacketID: 1})
+	require.Equal(t, storage.InflightKey+"_cl1:1", k)
+}
+
+func TestSysInfoKey(t *testing.T) {
+	require.Equal(t, storage.SysInfoKey, sysInfoKey())
+}
+
+func TestID(t *testing.T) {
+	h := new(Hook)
+	require.Equal(t, "bolt-db", h.ID())
+}
+
+func TestProvides(t *testing.T) {
+	h := new(Hook)
+	require.True(t, h.Provides(mqtt.OnSessionEstablished))
+	require.True(t, h.Provides(mqtt.OnDisconnect))
+	require.True(t, h.Provides(mqtt.OnSubscribed))
+	require.True(t, h.Provides(mqtt.OnUnsubscribed))
+	require.True(t, h.Provides(mqtt.OnRetainMessage))
+	require.True(t, h.Provides(mqtt.OnQosPublish))
+	require.True(t, h.Provides(mqtt.OnQosComplete))
+	require.True(t, h.Provides(mqtt.OnQosDropped))
+	require.True(t, h.Provides(mqtt.OnSysInfoTick))
+	require.True(t, h.Provides(mqtt.StoredClients))
+	require.True(t, h.Provides(mqtt.StoredInflightMessages))
+	require.True(t, h.Provides(mqtt.StoredRetainedMessages))
+	require.True(t, h.Provides(mqtt.StoredSubscriptions))
+	require.True(t, h.Provides(mqtt.StoredSysInfo))
+	require.False(t, h.Provides(mqtt.OnACLCheck))
+	require.False(t, h.Provides(mqtt.OnConnectAuthenticate))
+}
+
+func TestInitBadConfig(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(map[string]any{})
+	require.Error(t, err)
+}
+
+func TestInitUseDefaults(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	require.Equal(t, defaultTimeout, h.config.Options.Timeout)
+	require.Equal(t, defaultDbFile, h.config.Path)
+}
+
+func TestInitBadPath(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(&Options{
+		Path: "..",
+	})
+	require.Error(t, err)
+}
+
+func TestOnSessionEstablishedThenOnDisconnect(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	h.OnSessionEstablished(client, packets.Packet{})
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey(client), r)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.ID)
+	require.Equal(t, client.Net.Remote, r.Remote)
+	require.Equal(t, client.Net.Listener, r.Listener)
+	require.Equal(t, client.Properties.Username, r.Username)
+	require.Equal(t, client.Properties.Clean, r.Clean)
+	require.NotSame(t, client, r)
+
+	h.OnDisconnect(client, nil, false)
+	r2 := new(storage.Client)
+	err = h.getKv(clientKey(client), r2)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.ID)
+
+	h.OnDisconnect(client, nil, true)
+	r3 := new(storage.Client)
+	err = h.getKv(clientKey(client), r3)
+	require.Error(t, err)
+	require.ErrorIs(t, ErrKeyNotFound, err)
+	require.Empty(t, r3.ID)
+}
+
+func TestOnSessionEstablishedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSessionEstablished(client, packets.Packet{})
+}
+
+func TestOnSessionEstablishedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSessionEstablished(client, packets.Packet{})
+}
+
+func TestOnWillSent(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	c1 := client
+	c1.Properties.Will.Flag = 1
+	h.OnWillSent(c1, packets.Packet{})
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey(client), r)
+	require.NoError(t, err)
+
+	require.Equal(t, uint32(1), r.Will.Flag)
+	require.NotSame(t, client, r)
+}
+
+func TestOnClientExpired(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	cl := &mqtt.Client{ID: "cl1"}
+	clientKey := clientKey(cl)
+
+	err = h.setKv(clientKey, &storage.Client{ID: cl.ID})
+	require.NoError(t, err)
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey, r)
+	require.NoError(t, err)
+	require.Equal(t, cl.ID, r.ID)
+
+	h.OnClientExpired(cl)
+	err = h.getKv(clientKey, r)
+	require.Error(t, err)
+	require.ErrorIs(t, ErrKeyNotFound, err)
+}
+
+func TestOnClientExpiredClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnClientExpired(client)
+}
+
+func TestOnClientExpiredNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnClientExpired(client)
+}
+
+func TestOnDisconnectNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnDisconnect(client, nil, false)
+}
+
+func TestOnDisconnectClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnDisconnect(client, nil, false)
+}
+
+func TestOnDisconnectSessionTakenOver(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+
+	testClient := &mqtt.Client{
+		ID: "test",
+		Net: mqtt.ClientConnection{
+			Remote:   "test.addr",
+			Listener: "listener",
+		},
+		Properties: mqtt.ClientProperties{
+			Username: []byte("username"),
+			Clean:    false,
+		},
+	}
+
+	testClient.Stop(packets.ErrSessionTakenOver)
+	teardown(t, h.config.Path, h)
+	h.OnDisconnect(testClient, nil, true)
+}
+
+func TestOnSubscribedThenOnUnsubscribed(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	h.OnSubscribed(client, pkf, []byte{0})
+	r := new(storage.Subscription)
+
+	err = h.getKv(subscriptionKey(client, pkf.Filters[0].Filter), r)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.Client)
+	require.Equal(t, pkf.Filters[0].Filter, r.Filter)
+	require.Equal(t, byte(0), r.Qos)
+
+	h.OnUnsubscribed(client, pkf)
+	err = h.getKv(subscriptionKey(client, pkf.Filters[0].Filter), r)
+	require.Error(t, err)
+	require.Equal(t, ErrKeyNotFound, err)
+}
+
+func TestOnSubscribedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSubscribed(client, pkf, []byte{0})
+}
+
+func TestOnSubscribedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSubscribed(client, pkf, []byte{0})
+}
+
+func TestOnUnsubscribedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnUnsubscribed(client, pkf)
+}
+
+func TestOnUnsubscribedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnUnsubscribed(client, pkf)
+}
+
+func TestOnRetainMessageThenUnset(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	pk := packets.Packet{
+		FixedHeader: packets.FixedHeader{
+			Retain: true,
+		},
+		Payload:   []byte("hello"),
+		TopicName: "a/b/c",
+	}
+
+	h.OnRetainMessage(client, pk, 1)
+
+	r := new(storage.Message)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.NoError(t, err)
+	require.Equal(t, pk.TopicName, r.TopicName)
+	require.Equal(t, pk.Payload, r.Payload)
+
+	h.OnRetainMessage(client, pk, -1)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.Error(t, err)
+	require.Equal(t, ErrKeyNotFound, err)
+
+	// coverage: delete deleted
+	h.OnRetainMessage(client, pk, -1)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.Error(t, err)
+	require.Equal(t, ErrKeyNotFound, err)
+}
+
+func TestOnRetainedExpired(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	m := &storage.Message{
+		ID:        retainedKey("a/b/c"),
+		T:         storage.RetainedKey,
+		TopicName: "a/b/c",
+	}
+
+	err = h.setKv(m.ID, m)
+	require.NoError(t, err)
+
+	r := new(storage.Message)
+	err = h.getKv(m.ID, r)
+	require.NoError(t, err)
+	require.Equal(t, m.TopicName, r.TopicName)
+
+	h.OnRetainedExpired(m.TopicName)
+	err = h.getKv(m.ID, r)
+	require.Error(t, err)
+	require.Equal(t, ErrKeyNotFound, err)
+}
+
+func TestOnRetainedExpiredClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnRetainedExpired("a/b/c")
+}
+
+func TestOnRetainedExpiredNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnRetainedExpired("a/b/c")
+}
+
+func TestOnRetainMessageNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnRetainMessage(client, packets.Packet{}, 0)
+}
+
+func TestOnRetainMessageClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnRetainMessage(client, packets.Packet{}, 0)
+}
+
+func TestOnQosPublishThenQOSComplete(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	pk := packets.Packet{
+		FixedHeader: packets.FixedHeader{
+			Retain: true,
+			Qos:    2,
+		},
+		Payload:   []byte("hello"),
+		TopicName: "a/b/c",
+	}
+
+	h.OnQosPublish(client, pk, time.Now().Unix(), 0)
+
+	r := new(storage.Message)
+	err = h.getKv(inflightKey(client, pk), r)
+	require.NoError(t, err)
+	require.Equal(t, pk.TopicName, r.TopicName)
+	require.Equal(t, pk.Payload, r.Payload)
+
+	// ensure dates are properly saved to bolt
+	require.True(t, r.Sent > 0)
+	require.True(t, time.Now().Unix()-1 < r.Sent)
+
+	// OnQosDropped is a passthrough to OnQosComplete here
+	h.OnQosDropped(client, pk)
+	err = h.getKv(inflightKey(client, pk), r)
+	require.Error(t, err)
+	require.Equal(t, ErrKeyNotFound, err)
+}
+
+func TestOnQosPublishNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosPublish(client, packets.Packet{}, time.Now().Unix(), 0)
+}
+
+func TestOnQosPublishClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnQosPublish(client, packets.Packet{}, time.Now().Unix(), 0)
+}
+
+func TestOnQosCompleteNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosComplete(client, packets.Packet{})
+}
+
+func TestOnQosCompleteClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnQosComplete(client, packets.Packet{})
+}
+
+func TestOnQosDroppedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosDropped(client, packets.Packet{})
+}
+
+func TestOnSysInfoTick(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	info := &system.Info{
+		Version:       "2.0.0",
+		BytesReceived: 100,
+	}
+
+	h.OnSysInfoTick(info)
+
+	r := new(storage.SystemInfo)
+	err = h.getKv(storage.SysInfoKey, r)
+	require.NoError(t, err)
+	require.Equal(t, info.Version, r.Version)
+	require.Equal(t, info.BytesReceived, r.BytesReceived)
+	require.NotSame(t, info, r)
+}
+
+func TestOnSysInfoTickNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSysInfoTick(new(system.Info))
+}
+
+func TestOnSysInfoTickClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSysInfoTick(new(system.Info))
+}
+
+func TestStoredClients(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with clients
+	err = h.setKv(storage.ClientKey+"_"+"cl1", &storage.Client{ID: "cl1"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.ClientKey+"_"+"cl2", &storage.Client{ID: "cl2"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.ClientKey+"_"+"cl3", &storage.Client{ID: "cl3"})
+	require.NoError(t, err)
+
+	r, err := h.StoredClients()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "cl1", r[0].ID)
+	require.Equal(t, "cl2", r[1].ID)
+	require.Equal(t, "cl3", r[2].ID)
+}
+
+func TestStoredClientsNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredClients()
+	require.Empty(t, v)
+	require.ErrorIs(t, storage.ErrDBFileNotOpen, err)
+}
+
+func TestStoredClientsClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	v, err := h.StoredClients()
+	require.Empty(t, v)
+	require.ErrorIs(t, storage.ErrDBFileNotOpen, err)
+}
+
+func TestStoredSubscriptions(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with subscriptions
+	err = h.setKv(storage.SubscriptionKey+"_"+"sub1", &storage.Subscription{ID: "sub1"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.SubscriptionKey+"_"+"sub2", &storage.Subscription{ID: "sub2"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.SubscriptionKey+"_"+"sub3", &storage.Subscription{ID: "sub3"})
+	require.NoError(t, err)
+
+	r, err := h.StoredSubscriptions()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "sub1", r[0].ID)
+	require.Equal(t, "sub2", r[1].ID)
+	require.Equal(t, "sub3", r[2].ID)
+}
+
+func TestStoredSubscriptionsNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredSubscriptions()
+	require.Empty(t, v)
+	require.ErrorIs(t, storage.ErrDBFileNotOpen, err)
+}
+
+func TestStoredSubscriptionsClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	v, err := h.StoredSubscriptions()
+	require.Empty(t, v)
+	require.ErrorIs(t, storage.ErrDBFileNotOpen, err)
+}
+
+func TestStoredRetainedMessages(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with messages
+	err = h.setKv(storage.RetainedKey+"_"+"m1", &storage.Message{ID: "m1"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_"+"m2", &storage.Message{ID: "m2"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_"+"m3", &storage.Message{ID: "m3"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_"+"i3", &storage.Message{ID: "i3"})
+	require.NoError(t, err)
+
+	r, err := h.StoredRetainedMessages()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "m1", r[0].ID)
+	require.Equal(t, "m2", r[1].ID)
+	require.Equal(t, "m3", r[2].ID)
+}
+
+func TestStoredRetainedMessagesNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredRetainedMessages()
+	require.Empty(t, v)
+	require.ErrorIs(t, storage.ErrDBFileNotOpen, err)
+}
+
+func TestStoredRetainedMessagesClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	v, err := h.StoredRetainedMessages()
+	require.Empty(t, v)
+	require.Error(t, err)
+}
+
+func TestStoredInflightMessages(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with messages
+	err = h.setKv(storage.InflightKey+"_"+"i1", &storage.Message{ID: "i1"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_"+"i2", &storage.Message{ID: "i2"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_"+"i3", &storage.Message{ID: "i3"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_"+"m1", &storage.Message{ID: "m1"})
+	require.NoError(t, err)
+
+	r, err := h.StoredInflightMessages()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "i1", r[0].ID)
+	require.Equal(t, "i2", r[1].ID)
+	require.Equal(t, "i3", r[2].ID)
+}
+
+func TestStoredInflightMessagesNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredInflightMessages()
+	require.Empty(t, v)
+	require.ErrorIs(t, storage.ErrDBFileNotOpen, err)
+}
+
+func TestStoredInflightMessagesClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	v, err := h.StoredInflightMessages()
+	require.Empty(t, v)
+	require.ErrorIs(t, storage.ErrDBFileNotOpen, err)
+}
+
+func TestStoredSysInfo(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with sys info
+	err = h.setKv(storage.SysInfoKey, &storage.SystemInfo{
+		ID: storage.SysInfoKey,
+		Info: system.Info{
+			Version: "2.0.0",
+		},
+		T: storage.SysInfoKey,
+	})
+	require.NoError(t, err)
+
+	r, err := h.StoredSysInfo()
+	require.NoError(t, err)
+	require.Equal(t, "2.0.0", r.Info.Version)
+}
+
+func TestStoredSysInfoNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredSysInfo()
+	require.Empty(t, v)
+	require.ErrorIs(t, storage.ErrDBFileNotOpen, err)
+}
+
+func TestStoredSysInfoClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	v, err := h.StoredSysInfo()
+	require.Empty(t, v)
+	require.Error(t, err)
+}
+
+func TestGetSetDelKv(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	defer teardown(t, h.config.Path, h)
+	require.NoError(t, err)
+
+	err = h.setKv("testId", &storage.Client{ID: "testId"})
+	require.NoError(t, err)
+
+	var obj storage.Client
+	err = h.getKv("testId", &obj)
+	require.NoError(t, err)
+
+	err = h.delKv("testId")
+	require.NoError(t, err)
+
+	err = h.getKv("testId", &obj)
+	require.Error(t, err)
+	require.ErrorIs(t, ErrKeyNotFound, err)
+}
+
+func TestIterKv(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(nil)
+	defer teardown(t, h.config.Path, h)
+	require.NoError(t, err)
+
+	h.setKv("prefix_a_1", &storage.Client{ID: "1"})
+	h.setKv("prefix_a_2", &storage.Client{ID: "2"})
+	h.setKv("prefix_b_2", &storage.Client{ID: "3"})
+
+	var clients []storage.Client
+	err = h.iterKv("prefix_a", func(data []byte) error {
+		var item storage.Client
+		item.UnmarshalBinary(data)
+		clients = append(clients, item)
+		return nil
+	})
+	require.Equal(t, 2, len(clients))
+	require.NoError(t, err)
+
+	visitErr := errors.New("iter visit error")
+	err = h.iterKv("prefix_b", func(data []byte) error {
+		return visitErr
+	})
+	require.ErrorIs(t, visitErr, err)
+}

hooks/storage/pebble/pebble.go

@@ -0,0 +1,524 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: werbenhu
+
+package pebble
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strings"
+
+	pebbledb "github.com/cockroachdb/pebble"
+	"testmqtt/hooks/storage"
+	"testmqtt/mqtt"
+	"testmqtt/packets"
+	"testmqtt/system"
+)
+
+const (
+	// defaultDbFile is the default file path for the pebble db file.
+	defaultDbFile = ".pebble"
+)
+
+// clientKey returns a primary key for a client.
+func clientKey(cl *mqtt.Client) string {
+	return storage.ClientKey + "_" + cl.ID
+}
+
+// subscriptionKey returns a primary key for a subscription.
+func subscriptionKey(cl *mqtt.Client, filter string) string {
+	return storage.SubscriptionKey + "_" + cl.ID + ":" + filter
+}
+
+// retainedKey returns a primary key for a retained message.
+func retainedKey(topic string) string {
+	return storage.RetainedKey + "_" + topic
+}
+
+// inflightKey returns a primary key for an inflight message.
+func inflightKey(cl *mqtt.Client, pk packets.Packet) string {
+	return storage.InflightKey + "_" + cl.ID + ":" + pk.FormatID()
+}
+
+// sysInfoKey returns a primary key for system info.
+func sysInfoKey() string {
+	return storage.SysInfoKey
+}
+
+// keyUpperBound returns the upper bound for a given byte slice by incrementing the last byte.
+// It returns nil if all bytes are incremented and equal to 0.
+func keyUpperBound(b []byte) []byte {
+	end := make([]byte, len(b))
+	copy(end, b)
+	for i := len(end) - 1; i >= 0; i-- {
+		end[i] = end[i] + 1
+		if end[i] != 0 {
+			return end[:i+1]
+		}
+	}
+	return nil
+}
+
+const (
+	NoSync = "NoSync" // NoSync specifies the default write options for writes which do not synchronize to disk.
+	Sync   = "Sync"   // Sync specifies the default write options for writes which synchronize to disk.
+)
+
+// Options contains configuration settings for the pebble DB instance.
+type Options struct {
+	Options *pebbledb.Options
+	Mode    string `yaml:"mode" json:"mode"`
+	Path    string `yaml:"path" json:"path"`
+}
+
+// Hook is a persistent storage hook based using pebble DB file store as a backend.
+type Hook struct {
+	mqtt.HookBase
+	config *Options               // options for configuring the pebble DB instance.
+	db     *pebbledb.DB           // the pebble DB instance
+	mode   *pebbledb.WriteOptions // mode holds the optional per-query parameters for Set and Delete operations
+}
+
+// ID returns the id of the hook.
+func (h *Hook) ID() string {
+	return "pebble-db"
+}
+
+// Provides indicates which hook methods this hook provides.
+func (h *Hook) Provides(b byte) bool {
+	return bytes.Contains([]byte{
+		mqtt.OnSessionEstablished,
+		mqtt.OnDisconnect,
+		mqtt.OnSubscribed,
+		mqtt.OnUnsubscribed,
+		mqtt.OnRetainMessage,
+		mqtt.OnWillSent,
+		mqtt.OnQosPublish,
+		mqtt.OnQosComplete,
+		mqtt.OnQosDropped,
+		mqtt.OnSysInfoTick,
+		mqtt.OnClientExpired,
+		mqtt.OnRetainedExpired,
+		mqtt.StoredClients,
+		mqtt.StoredInflightMessages,
+		mqtt.StoredRetainedMessages,
+		mqtt.StoredSubscriptions,
+		mqtt.StoredSysInfo,
+	}, []byte{b})
+}
+
+// Init initializes and connects to the pebble instance.
+func (h *Hook) Init(config any) error {
+	if _, ok := config.(*Options); !ok && config != nil {
+		return mqtt.ErrInvalidConfigType
+	}
+
+	if config == nil {
+		h.config = new(Options)
+	} else {
+		h.config = config.(*Options)
+	}
+
+	if len(h.config.Path) == 0 {
+		h.config.Path = defaultDbFile
+	}
+
+	if h.config.Options == nil {
+		h.config.Options = &pebbledb.Options{}
+	}
+
+	h.mode = pebbledb.NoSync
+	if strings.EqualFold(h.config.Mode, "Sync") {
+		h.mode = pebbledb.Sync
+	}
+
+	var err error
+	h.db, err = pebbledb.Open(h.config.Path, h.config.Options)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Stop closes the pebble instance.
+func (h *Hook) Stop() error {
+	err := h.db.Close()
+	h.db = nil
+	return err
+}
+
+// OnSessionEstablished adds a client to the store when their session is established.
+func (h *Hook) OnSessionEstablished(cl *mqtt.Client, pk packets.Packet) {
+	h.updateClient(cl)
+}
+
+// OnWillSent is called when a client sends a Will Message and the Will Message is removed from the client record.
+func (h *Hook) OnWillSent(cl *mqtt.Client, pk packets.Packet) {
+	h.updateClient(cl)
+}
+
+// updateClient writes the client data to the store.
+func (h *Hook) updateClient(cl *mqtt.Client) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	props := cl.Properties.Props.Copy(false)
+	in := &storage.Client{
+		ID:              cl.ID,
+		T:               storage.ClientKey,
+		Remote:          cl.Net.Remote,
+		Listener:        cl.Net.Listener,
+		Username:        cl.Properties.Username,
+		Clean:           cl.Properties.Clean,
+		ProtocolVersion: cl.Properties.ProtocolVersion,
+		Properties: storage.ClientProperties{
+			SessionExpiryInterval: props.SessionExpiryInterval,
+			AuthenticationMethod:  props.AuthenticationMethod,
+			AuthenticationData:    props.AuthenticationData,
+			RequestProblemInfo:    props.RequestProblemInfo,
+			RequestResponseInfo:   props.RequestResponseInfo,
+			ReceiveMaximum:        props.ReceiveMaximum,
+			TopicAliasMaximum:     props.TopicAliasMaximum,
+			User:                  props.User,
+			MaximumPacketSize:     props.MaximumPacketSize,
+		},
+		Will: storage.ClientWill(cl.Properties.Will),
+	}
+	h.setKv(clientKey(cl), in)
+}
+
+// OnDisconnect removes a client from the store if their session has expired.
+func (h *Hook) OnDisconnect(cl *mqtt.Client, _ error, expire bool) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	h.updateClient(cl)
+
+	if !expire {
+		return
+	}
+
+	if errors.Is(cl.StopCause(), packets.ErrSessionTakenOver) {
+		return
+	}
+
+	h.delKv(clientKey(cl))
+}
+
+// OnSubscribed adds one or more client subscriptions to the store.
+func (h *Hook) OnSubscribed(cl *mqtt.Client, pk packets.Packet, reasonCodes []byte) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	var in *storage.Subscription
+	for i := 0; i < len(pk.Filters); i++ {
+		in = &storage.Subscription{
+			ID:                subscriptionKey(cl, pk.Filters[i].Filter),
+			T:                 storage.SubscriptionKey,
+			Client:            cl.ID,
+			Qos:               reasonCodes[i],
+			Filter:            pk.Filters[i].Filter,
+			Identifier:        pk.Filters[i].Identifier,
+			NoLocal:           pk.Filters[i].NoLocal,
+			RetainHandling:    pk.Filters[i].RetainHandling,
+			RetainAsPublished: pk.Filters[i].RetainAsPublished,
+		}
+		h.setKv(in.ID, in)
+	}
+}
+
+// OnUnsubscribed removes one or more client subscriptions from the store.
+func (h *Hook) OnUnsubscribed(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	for i := 0; i < len(pk.Filters); i++ {
+		h.delKv(subscriptionKey(cl, pk.Filters[i].Filter))
+	}
+}
+
+// OnRetainMessage adds a retained message for a topic to the store.
+func (h *Hook) OnRetainMessage(cl *mqtt.Client, pk packets.Packet, r int64) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	if r == -1 {
+		h.delKv(retainedKey(pk.TopicName))
+		return
+	}
+
+	props := pk.Properties.Copy(false)
+	in := &storage.Message{
+		ID:          retainedKey(pk.TopicName),
+		T:           storage.RetainedKey,
+		FixedHeader: pk.FixedHeader,
+		TopicName:   pk.TopicName,
+		Payload:     pk.Payload,
+		Created:     pk.Created,
+		Origin:      pk.Origin,
+		Properties: storage.MessageProperties{
+			PayloadFormat:          props.PayloadFormat,
+			MessageExpiryInterval:  props.MessageExpiryInterval,
+			ContentType:            props.ContentType,
+			ResponseTopic:          props.ResponseTopic,
+			CorrelationData:        props.CorrelationData,
+			SubscriptionIdentifier: props.SubscriptionIdentifier,
+			TopicAlias:             props.TopicAlias,
+			User:                   props.User,
+		},
+	}
+
+	h.setKv(in.ID, in)
+}
+
+// OnQosPublish adds or updates an inflight message in the store.
+func (h *Hook) OnQosPublish(cl *mqtt.Client, pk packets.Packet, sent int64, resends int) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	props := pk.Properties.Copy(false)
+	in := &storage.Message{
+		ID:          inflightKey(cl, pk),
+		T:           storage.InflightKey,
+		Origin:      pk.Origin,
+		PacketID:    pk.PacketID,
+		FixedHeader: pk.FixedHeader,
+		TopicName:   pk.TopicName,
+		Payload:     pk.Payload,
+		Sent:        sent,
+		Created:     pk.Created,
+		Properties: storage.MessageProperties{
+			PayloadFormat:          props.PayloadFormat,
+			MessageExpiryInterval:  props.MessageExpiryInterval,
+			ContentType:            props.ContentType,
+			ResponseTopic:          props.ResponseTopic,
+			CorrelationData:        props.CorrelationData,
+			SubscriptionIdentifier: props.SubscriptionIdentifier,
+			TopicAlias:             props.TopicAlias,
+			User:                   props.User,
+		},
+	}
+	h.setKv(in.ID, in)
+}
+
+// OnQosComplete removes a resolved inflight message from the store.
+func (h *Hook) OnQosComplete(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+	h.delKv(inflightKey(cl, pk))
+}
+
+// OnQosDropped removes a dropped inflight message from the store.
+func (h *Hook) OnQosDropped(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+	}
+
+	h.OnQosComplete(cl, pk)
+}
+
+// OnSysInfoTick stores the latest system info in the store.
+func (h *Hook) OnSysInfoTick(sys *system.Info) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	in := &storage.SystemInfo{
+		ID:   sysInfoKey(),
+		T:    storage.SysInfoKey,
+		Info: *sys.Clone(),
+	}
+	h.setKv(in.ID, in)
+}
+
+// OnRetainedExpired deletes expired retained messages from the store.
+func (h *Hook) OnRetainedExpired(filter string) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+	h.delKv(retainedKey(filter))
+}
+
+// OnClientExpired deleted expired clients from the store.
+func (h *Hook) OnClientExpired(cl *mqtt.Client) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+	h.delKv(clientKey(cl))
+}
+
+// StoredClients returns all stored clients from the store.
+func (h *Hook) StoredClients() (v []storage.Client, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	iter, _ := h.db.NewIter(&pebbledb.IterOptions{
+		LowerBound: []byte(storage.ClientKey),
+		UpperBound: keyUpperBound([]byte(storage.ClientKey)),
+	})
+
+	for iter.First(); iter.Valid(); iter.Next() {
+		item := storage.Client{}
+		if err := item.UnmarshalBinary(iter.Value()); err == nil {
+			v = append(v, item)
+		}
+	}
+	return v, nil
+}
+
+// StoredSubscriptions returns all stored subscriptions from the store.
+func (h *Hook) StoredSubscriptions() (v []storage.Subscription, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	iter, _ := h.db.NewIter(&pebbledb.IterOptions{
+		LowerBound: []byte(storage.SubscriptionKey),
+		UpperBound: keyUpperBound([]byte(storage.SubscriptionKey)),
+	})
+
+	for iter.First(); iter.Valid(); iter.Next() {
+		item := storage.Subscription{}
+		if err := item.UnmarshalBinary(iter.Value()); err == nil {
+			v = append(v, item)
+		}
+	}
+	return v, nil
+}
+
+// StoredRetainedMessages returns all stored retained messages from the store.
+func (h *Hook) StoredRetainedMessages() (v []storage.Message, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	iter, _ := h.db.NewIter(&pebbledb.IterOptions{
+		LowerBound: []byte(storage.RetainedKey),
+		UpperBound: keyUpperBound([]byte(storage.RetainedKey)),
+	})
+
+	for iter.First(); iter.Valid(); iter.Next() {
+		item := storage.Message{}
+		if err := item.UnmarshalBinary(iter.Value()); err == nil {
+			v = append(v, item)
+		}
+	}
+	return v, nil
+}
+
+// StoredInflightMessages returns all stored inflight messages from the store.
+func (h *Hook) StoredInflightMessages() (v []storage.Message, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	iter, _ := h.db.NewIter(&pebbledb.IterOptions{
+		LowerBound: []byte(storage.InflightKey),
+		UpperBound: keyUpperBound([]byte(storage.InflightKey)),
+	})
+
+	for iter.First(); iter.Valid(); iter.Next() {
+		item := storage.Message{}
+		if err := item.UnmarshalBinary(iter.Value()); err == nil {
+			v = append(v, item)
+		}
+	}
+	return v, nil
+}
+
+// StoredSysInfo returns the system info from the store.
+func (h *Hook) StoredSysInfo() (v storage.SystemInfo, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	err = h.getKv(sysInfoKey(), &v)
+	if errors.Is(err, pebbledb.ErrNotFound) {
+		return v, nil
+	}
+
+	return
+}
+
+// Errorf satisfies the pebble interface for an error logger.
+func (h *Hook) Errorf(m string, v ...any) {
+	h.Log.Error(fmt.Sprintf(strings.ToLower(strings.Trim(m, "\n")), v...), "v", v)
+
+}
+
+// Warningf satisfies the pebble interface for a warning logger.
+func (h *Hook) Warningf(m string, v ...any) {
+	h.Log.Warn(fmt.Sprintf(strings.ToLower(strings.Trim(m, "\n")), v...), "v", v)
+}
+
+// Infof satisfies the pebble interface for an info logger.
+func (h *Hook) Infof(m string, v ...any) {
+	h.Log.Info(fmt.Sprintf(strings.ToLower(strings.Trim(m, "\n")), v...), "v", v)
+}
+
+// Debugf satisfies the pebble interface for a debug logger.
+func (h *Hook) Debugf(m string, v ...any) {
+	h.Log.Debug(fmt.Sprintf(strings.ToLower(strings.Trim(m, "\n")), v...), "v", v)
+}
+
+// delKv deletes a key-value pair from the database.
+func (h *Hook) delKv(k string) error {
+	err := h.db.Delete([]byte(k), h.mode)
+	if err != nil {
+		h.Log.Error("failed to delete data", "error", err, "key", k)
+		return err
+	}
+	return nil
+}
+
+// setKv stores a key-value pair in the database.
+func (h *Hook) setKv(k string, v storage.Serializable) error {
+	bs, _ := v.MarshalBinary()
+	err := h.db.Set([]byte(k), bs, h.mode)
+	if err != nil {
+		h.Log.Error("failed to update data", "error", err, "key", k)
+		return err
+	}
+	return nil
+}
+
+// getKv retrieves the value associated with a key from the database.
+func (h *Hook) getKv(k string, v storage.Serializable) error {
+	value, closer, err := h.db.Get([]byte(k))
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		if closer != nil {
+			closer.Close()
+		}
+	}()
+	return v.UnmarshalBinary(value)
+}

hooks/storage/pebble/pebble_test.go

@@ -0,0 +1,812 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: werbenhu
+
+package pebble
+
+import (
+	"log/slog"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	pebbledb "github.com/cockroachdb/pebble"
+	"github.com/stretchr/testify/require"
+	"testmqtt/hooks/storage"
+	"testmqtt/mqtt"
+	"testmqtt/packets"
+	"testmqtt/system"
+)
+
+var (
+	logger = slog.New(slog.NewTextHandler(os.Stdout, nil))
+
+	client = &mqtt.Client{
+		ID: "test",
+		Net: mqtt.ClientConnection{
+			Remote:   "test.addr",
+			Listener: "listener",
+		},
+		Properties: mqtt.ClientProperties{
+			Username: []byte("username"),
+			Clean:    false,
+		},
+	}
+
+	pkf = packets.Packet{Filters: packets.Subscriptions{{Filter: "a/b/c"}}}
+)
+
+func teardown(t *testing.T, path string, h *Hook) {
+	_ = h.Stop()
+	err := os.RemoveAll("./" + strings.Replace(path, "..", "", -1))
+	require.NoError(t, err)
+}
+
+func TestKeyUpperBound(t *testing.T) {
+	// Test case 1: Non-nil case
+	input1 := []byte{97, 98, 99} // "abc"
+	require.NotNil(t, keyUpperBound(input1))
+
+	// Test case 2: All bytes are 255
+	input2 := []byte{255, 255, 255}
+	require.Nil(t, keyUpperBound(input2))
+
+	// Test case 3: Empty slice
+	input3 := []byte{}
+	require.Nil(t, keyUpperBound(input3))
+
+	// Test case 4: Nil case
+	input4 := []byte{255, 255, 255}
+	require.Nil(t, keyUpperBound(input4))
+}
+
+func TestClientKey(t *testing.T) {
+	k := clientKey(&mqtt.Client{ID: "cl1"})
+	require.Equal(t, storage.ClientKey+"_cl1", k)
+}
+
+func TestSubscriptionKey(t *testing.T) {
+	k := subscriptionKey(&mqtt.Client{ID: "cl1"}, "a/b/c")
+	require.Equal(t, storage.SubscriptionKey+"_cl1:a/b/c", k)
+}
+
+func TestRetainedKey(t *testing.T) {
+	k := retainedKey("a/b/c")
+	require.Equal(t, storage.RetainedKey+"_a/b/c", k)
+}
+
+func TestInflightKey(t *testing.T) {
+	k := inflightKey(&mqtt.Client{ID: "cl1"}, packets.Packet{PacketID: 1})
+	require.Equal(t, storage.InflightKey+"_cl1:1", k)
+}
+
+func TestSysInfoKey(t *testing.T) {
+	require.Equal(t, storage.SysInfoKey, sysInfoKey())
+}
+
+func TestID(t *testing.T) {
+	h := new(Hook)
+	require.Equal(t, "pebble-db", h.ID())
+}
+
+func TestProvides(t *testing.T) {
+	h := new(Hook)
+	require.True(t, h.Provides(mqtt.OnSessionEstablished))
+	require.True(t, h.Provides(mqtt.OnDisconnect))
+	require.True(t, h.Provides(mqtt.OnSubscribed))
+	require.True(t, h.Provides(mqtt.OnUnsubscribed))
+	require.True(t, h.Provides(mqtt.OnRetainMessage))
+	require.True(t, h.Provides(mqtt.OnQosPublish))
+	require.True(t, h.Provides(mqtt.OnQosComplete))
+	require.True(t, h.Provides(mqtt.OnQosDropped))
+	require.True(t, h.Provides(mqtt.OnSysInfoTick))
+	require.True(t, h.Provides(mqtt.StoredClients))
+	require.True(t, h.Provides(mqtt.StoredInflightMessages))
+	require.True(t, h.Provides(mqtt.StoredRetainedMessages))
+	require.True(t, h.Provides(mqtt.StoredSubscriptions))
+	require.True(t, h.Provides(mqtt.StoredSysInfo))
+	require.False(t, h.Provides(mqtt.OnACLCheck))
+	require.False(t, h.Provides(mqtt.OnConnectAuthenticate))
+}
+
+func TestInitBadConfig(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(map[string]any{})
+	require.Error(t, err)
+}
+
+func TestInitErr(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(&Options{
+		Options: &pebbledb.Options{
+			ReadOnly: true,
+		},
+	})
+	require.Error(t, err)
+}
+
+func TestInitUseDefaults(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	require.Equal(t, defaultDbFile, h.config.Path)
+}
+
+func TestOnSessionEstablishedThenOnDisconnect(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	h.OnSessionEstablished(client, packets.Packet{})
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey(client), r)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.ID)
+	require.Equal(t, client.Properties.Username, r.Username)
+	require.Equal(t, client.Properties.Clean, r.Clean)
+	require.Equal(t, client.Net.Remote, r.Remote)
+	require.Equal(t, client.Net.Listener, r.Listener)
+	require.NotSame(t, client, r)
+
+	h.OnDisconnect(client, nil, false)
+	r2 := new(storage.Client)
+	err = h.getKv(clientKey(client), r2)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.ID)
+
+	h.OnDisconnect(client, nil, true)
+	r3 := new(storage.Client)
+	err = h.getKv(clientKey(client), r3)
+	require.Error(t, err)
+	require.ErrorIs(t, pebbledb.ErrNotFound, err)
+	require.Empty(t, r3.ID)
+
+}
+
+func TestOnClientExpired(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	cl := &mqtt.Client{ID: "cl1"}
+	clientKey := clientKey(cl)
+
+	err = h.setKv(clientKey, &storage.Client{ID: cl.ID})
+	require.NoError(t, err)
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey, r)
+	require.NoError(t, err)
+	require.Equal(t, cl.ID, r.ID)
+
+	h.OnClientExpired(cl)
+	err = h.getKv(clientKey, r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, pebbledb.ErrNotFound)
+}
+
+func TestOnClientExpiredNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnClientExpired(client)
+}
+
+func TestOnClientExpiredClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnClientExpired(client)
+}
+
+func TestOnSessionEstablishedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSessionEstablished(client, packets.Packet{})
+}
+
+func TestOnSessionEstablishedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSessionEstablished(client, packets.Packet{})
+}
+
+func TestOnWillSent(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	c1 := client
+	c1.Properties.Will.Flag = 1
+	h.OnWillSent(c1, packets.Packet{})
+
+	r := new(storage.Client)
+	err = h.getKv(clientKey(client), r)
+	require.NoError(t, err)
+
+	require.Equal(t, uint32(1), r.Will.Flag)
+	require.NotSame(t, client, r)
+}
+
+func TestOnDisconnectNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnDisconnect(client, nil, false)
+}
+
+func TestOnDisconnectClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnDisconnect(client, nil, false)
+}
+
+func TestOnDisconnectSessionTakenOver(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+
+	testClient := &mqtt.Client{
+		ID: "test",
+		Net: mqtt.ClientConnection{
+			Remote:   "test.addr",
+			Listener: "listener",
+		},
+		Properties: mqtt.ClientProperties{
+			Username: []byte("username"),
+			Clean:    false,
+		},
+	}
+
+	testClient.Stop(packets.ErrSessionTakenOver)
+	h.OnDisconnect(testClient, nil, true)
+	teardown(t, h.config.Path, h)
+}
+
+func TestOnSubscribedThenOnUnsubscribed(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	h.OnSubscribed(client, pkf, []byte{0})
+	r := new(storage.Subscription)
+
+	err = h.getKv(subscriptionKey(client, pkf.Filters[0].Filter), r)
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.Client)
+	require.Equal(t, pkf.Filters[0].Filter, r.Filter)
+	require.Equal(t, byte(0), r.Qos)
+
+	h.OnUnsubscribed(client, pkf)
+	err = h.getKv(subscriptionKey(client, pkf.Filters[0].Filter), r)
+	require.Error(t, err)
+	require.Equal(t, pebbledb.ErrNotFound, err)
+}
+
+func TestOnSubscribedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSubscribed(client, pkf, []byte{0})
+}
+
+func TestOnSubscribedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSubscribed(client, pkf, []byte{0})
+}
+
+func TestOnUnsubscribedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnUnsubscribed(client, pkf)
+}
+
+func TestOnUnsubscribedClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnUnsubscribed(client, pkf)
+}
+
+func TestOnRetainMessageThenUnset(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	pk := packets.Packet{
+		FixedHeader: packets.FixedHeader{
+			Retain: true,
+		},
+		Payload:   []byte("hello"),
+		TopicName: "a/b/c",
+	}
+
+	h.OnRetainMessage(client, pk, 1)
+
+	r := new(storage.Message)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.NoError(t, err)
+	require.Equal(t, pk.TopicName, r.TopicName)
+	require.Equal(t, pk.Payload, r.Payload)
+
+	h.OnRetainMessage(client, pk, -1)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, pebbledb.ErrNotFound)
+
+	// coverage: delete deleted
+	h.OnRetainMessage(client, pk, -1)
+	err = h.getKv(retainedKey(pk.TopicName), r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, pebbledb.ErrNotFound)
+}
+
+func TestOnRetainedExpired(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	m := &storage.Message{
+		ID:        retainedKey("a/b/c"),
+		T:         storage.RetainedKey,
+		TopicName: "a/b/c",
+	}
+
+	err = h.setKv(m.ID, m)
+	require.NoError(t, err)
+
+	r := new(storage.Message)
+	err = h.getKv(m.ID, r)
+	require.NoError(t, err)
+	require.Equal(t, m.TopicName, r.TopicName)
+
+	h.OnRetainedExpired(m.TopicName)
+	err = h.getKv(m.ID, r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, pebbledb.ErrNotFound)
+}
+
+func TestOnRetainExpiredNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnRetainedExpired("a/b/c")
+}
+
+func TestOnRetainExpiredClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnRetainedExpired("a/b/c")
+}
+
+func TestOnRetainMessageNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnRetainMessage(client, packets.Packet{}, 0)
+}
+
+func TestOnRetainMessageClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnRetainMessage(client, packets.Packet{}, 0)
+}
+
+func TestOnQosPublishThenQOSComplete(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	pk := packets.Packet{
+		FixedHeader: packets.FixedHeader{
+			Retain: true,
+			Qos:    2,
+		},
+		Payload:   []byte("hello"),
+		TopicName: "a/b/c",
+	}
+
+	h.OnQosPublish(client, pk, time.Now().Unix(), 0)
+
+	r := new(storage.Message)
+	err = h.getKv(inflightKey(client, pk), r)
+	require.NoError(t, err)
+	require.Equal(t, pk.TopicName, r.TopicName)
+	require.Equal(t, pk.Payload, r.Payload)
+
+	// ensure dates are properly saved
+	require.True(t, r.Sent > 0)
+	require.True(t, time.Now().Unix()-1 < r.Sent)
+
+	// OnQosDropped is a passthrough to OnQosComplete here
+	h.OnQosDropped(client, pk)
+	err = h.getKv(inflightKey(client, pk), r)
+	require.Error(t, err)
+	require.ErrorIs(t, err, pebbledb.ErrNotFound)
+}
+
+func TestOnQosPublishNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosPublish(client, packets.Packet{}, time.Now().Unix(), 0)
+}
+
+func TestOnQosPublishClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnQosPublish(client, packets.Packet{}, time.Now().Unix(), 0)
+}
+
+func TestOnQosCompleteNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosComplete(client, packets.Packet{})
+}
+
+func TestOnQosCompleteClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnQosComplete(client, packets.Packet{})
+}
+
+func TestOnQosDroppedNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnQosDropped(client, packets.Packet{})
+}
+
+func TestOnSysInfoTick(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	info := &system.Info{
+		Version:       "2.0.0",
+		BytesReceived: 100,
+	}
+
+	h.OnSysInfoTick(info)
+
+	r := new(storage.SystemInfo)
+	err = h.getKv(storage.SysInfoKey, r)
+	require.NoError(t, err)
+	require.Equal(t, info.Version, r.Version)
+	require.Equal(t, info.BytesReceived, r.BytesReceived)
+	require.NotSame(t, info, r)
+}
+
+func TestOnSysInfoTickNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.OnSysInfoTick(new(system.Info))
+}
+
+func TestOnSysInfoTickClosedDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	teardown(t, h.config.Path, h)
+	h.OnSysInfoTick(new(system.Info))
+}
+
+func TestStoredClients(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with clients
+	err = h.setKv(storage.ClientKey+"_cl1", &storage.Client{ID: "cl1"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.ClientKey+"_cl2", &storage.Client{ID: "cl2"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.ClientKey+"_cl3", &storage.Client{ID: "cl3"})
+	require.NoError(t, err)
+
+	r, err := h.StoredClients()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "cl1", r[0].ID)
+	require.Equal(t, "cl2", r[1].ID)
+	require.Equal(t, "cl3", r[2].ID)
+}
+
+func TestStoredClientsNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredClients()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredSubscriptions(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with subscriptions
+	err = h.setKv(storage.SubscriptionKey+"_sub1", &storage.Subscription{ID: "sub1"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.SubscriptionKey+"_sub2", &storage.Subscription{ID: "sub2"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.SubscriptionKey+"_sub3", &storage.Subscription{ID: "sub3"})
+	require.NoError(t, err)
+
+	r, err := h.StoredSubscriptions()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "sub1", r[0].ID)
+	require.Equal(t, "sub2", r[1].ID)
+	require.Equal(t, "sub3", r[2].ID)
+}
+
+func TestStoredSubscriptionsNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredSubscriptions()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredRetainedMessages(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with messages
+	err = h.setKv(storage.RetainedKey+"_m1", &storage.Message{ID: "m1"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_m2", &storage.Message{ID: "m2"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_m3", &storage.Message{ID: "m3"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_i3", &storage.Message{ID: "i3"})
+	require.NoError(t, err)
+
+	r, err := h.StoredRetainedMessages()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "m1", r[0].ID)
+	require.Equal(t, "m2", r[1].ID)
+	require.Equal(t, "m3", r[2].ID)
+}
+
+func TestStoredRetainedMessagesNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredRetainedMessages()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredInflightMessages(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	// populate with messages
+	err = h.setKv(storage.InflightKey+"_i1", &storage.Message{ID: "i1"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_i2", &storage.Message{ID: "i2"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.InflightKey+"_i3", &storage.Message{ID: "i3"})
+	require.NoError(t, err)
+
+	err = h.setKv(storage.RetainedKey+"_m1", &storage.Message{ID: "m1"})
+	require.NoError(t, err)
+
+	r, err := h.StoredInflightMessages()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	require.Equal(t, "i1", r[0].ID)
+	require.Equal(t, "i2", r[1].ID)
+	require.Equal(t, "i3", r[2].ID)
+}
+
+func TestStoredInflightMessagesNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredInflightMessages()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredSysInfo(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	r, err := h.StoredSysInfo()
+	require.NoError(t, err)
+
+	// populate with messages
+	err = h.setKv(storage.SysInfoKey, &storage.SystemInfo{
+		ID: storage.SysInfoKey,
+		Info: system.Info{
+			Version: "2.0.0",
+		},
+		T: storage.SysInfoKey,
+	})
+	require.NoError(t, err)
+
+	r, err = h.StoredSysInfo()
+	require.NoError(t, err)
+	require.Equal(t, "2.0.0", r.Info.Version)
+}
+
+func TestStoredSysInfoNoDB(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	v, err := h.StoredSysInfo()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestErrorf(t *testing.T) {
+	// coverage: one day check log hook
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Errorf("test", 1, 2, 3)
+}
+
+func TestWarningf(t *testing.T) {
+	// coverage: one day check log hook
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Warningf("test", 1, 2, 3)
+}
+
+func TestInfof(t *testing.T) {
+	// coverage: one day check log hook
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Infof("test", 1, 2, 3)
+}
+
+func TestDebugf(t *testing.T) {
+	// coverage: one day check log hook
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	h.Debugf("test", 1, 2, 3)
+}
+
+func TestGetSetDelKv(t *testing.T) {
+	opts := []struct {
+		name string
+		opt  *Options
+	}{
+		{
+			name: "NoSync",
+			opt: &Options{
+				Mode: NoSync,
+			},
+		},
+		{
+			name: "Sync",
+			opt: &Options{
+				Mode: Sync,
+			},
+		},
+	}
+	for _, tt := range opts {
+		t.Run(tt.name, func(t *testing.T) {
+			h := new(Hook)
+			h.SetOpts(logger, nil)
+			err := h.Init(tt.opt)
+			defer teardown(t, h.config.Path, h)
+			require.NoError(t, err)
+
+			err = h.setKv("testKey", &storage.Client{ID: "testId"})
+			require.NoError(t, err)
+
+			var obj storage.Client
+			err = h.getKv("testKey", &obj)
+			require.NoError(t, err)
+
+			err = h.delKv("testKey")
+			require.NoError(t, err)
+
+			err = h.getKv("testKey", &obj)
+			require.Error(t, err)
+			require.ErrorIs(t, pebbledb.ErrNotFound, err)
+		})
+	}
+}
+
+func TestGetSetDelKvErr(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(&Options{
+		Mode: Sync,
+	})
+	require.NoError(t, err)
+
+	err = h.setKv("testKey", &storage.Client{ID: "testId"})
+	require.NoError(t, err)
+	h.Stop()
+
+	h = new(Hook)
+	h.SetOpts(logger, nil)
+
+	err = h.Init(&Options{
+		Mode: Sync,
+		Options: &pebbledb.Options{
+			ReadOnly: true,
+		},
+	})
+	require.NoError(t, err)
+	defer teardown(t, h.config.Path, h)
+
+	err = h.setKv("testKey", &storage.Client{ID: "testId"})
+	require.Error(t, err)
+
+	err = h.delKv("testKey")
+	require.Error(t, err)
+}

hooks/storage/redis/redis.go

@@ -0,0 +1,532 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: mochi-co
+
+package redis
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+
+	"testmqtt/hooks/storage"
+	"testmqtt/mqtt"
+	"testmqtt/packets"
+	"testmqtt/system"
+
+	"github.com/go-redis/redis/v8"
+)
+
+// defaultAddr 默认Redis地址
+// defaultAddr is the default address to the redis service.
+const defaultAddr = "localhost:6379"
+
+// defaultHPrefix 默认前缀
+// defaultHPrefix is a prefix to better identify hsets created by mochi mqtt.
+const defaultHPrefix = "mochi-"
+
+// clientKey returns a primary key for a client.
+func clientKey(cl *mqtt.Client) string {
+	return cl.ID
+}
+
+// subscriptionKey returns a primary key for a subscription.
+func subscriptionKey(cl *mqtt.Client, filter string) string {
+	return cl.ID + ":" + filter
+}
+
+// retainedKey returns a primary key for a retained message.
+func retainedKey(topic string) string {
+	return topic
+}
+
+// inflightKey returns a primary key for an inflight message.
+func inflightKey(cl *mqtt.Client, pk packets.Packet) string {
+	return cl.ID + ":" + pk.FormatID()
+}
+
+// sysInfoKey returns a primary key for system info.
+func sysInfoKey() string {
+	return storage.SysInfoKey
+}
+
+// Options contains configuration settings for the bolt instance.
+type Options struct {
+	Address  string `yaml:"address" json:"address"`
+	Username string `yaml:"username" json:"username"`
+	Password string `yaml:"password" json:"password"`
+	Database int    `yaml:"database" json:"database"`
+	HPrefix  string `yaml:"h_prefix" json:"h_prefix"`
+	Options  *redis.Options
+}
+
+// Hook is a persistent storage hook based using Redis as a backend.
+type Hook struct {
+	mqtt.HookBase
+	config *Options        // options for connecting to the Redis instance.
+	db     *redis.Client   // the Redis instance
+	ctx    context.Context // a context for the connection
+}
+
+// ID returns the id of the hook.
+func (h *Hook) ID() string {
+	return "redis-db"
+}
+
+// Provides indicates which hook methods this hook provides.
+func (h *Hook) Provides(b byte) bool {
+	return bytes.Contains([]byte{
+		mqtt.OnSessionEstablished,
+		mqtt.OnDisconnect,
+		mqtt.OnSubscribed,
+		mqtt.OnUnsubscribed,
+		mqtt.OnRetainMessage,
+		mqtt.OnQosPublish,
+		mqtt.OnQosComplete,
+		mqtt.OnQosDropped,
+		mqtt.OnWillSent,
+		mqtt.OnSysInfoTick,
+		mqtt.OnClientExpired,
+		mqtt.OnRetainedExpired,
+		mqtt.StoredClients,
+		mqtt.StoredInflightMessages,
+		mqtt.StoredRetainedMessages,
+		mqtt.StoredSubscriptions,
+		mqtt.StoredSysInfo,
+	}, []byte{b})
+}
+
+// hKey returns a hash set key with a unique prefix.
+func (h *Hook) hKey(s string) string {
+	return h.config.HPrefix + s
+}
+
+// Init 初始化并连接到 Redis 服务
+// Init initializes and connects to the redis service.
+func (h *Hook) Init(config any) error {
+
+	if _, ok := config.(*Options); !ok && config != nil {
+		return mqtt.ErrInvalidConfigType
+	}
+
+	h.ctx = context.Background()
+
+	if config == nil {
+		config = new(Options)
+	}
+	h.config = config.(*Options)
+	if h.config.Options == nil {
+		h.config.Options = &redis.Options{
+			Addr: defaultAddr,
+		}
+		h.config.Options.Addr = h.config.Address
+		h.config.Options.DB = h.config.Database
+		//h.config.Options.Username = h.config.Username
+		h.config.Options.Password = h.config.Password
+	}
+
+	if h.config.HPrefix == "" {
+		h.config.HPrefix = defaultHPrefix
+	}
+
+	h.Log.Info(
+		"connecting to redis service",
+		"prefix", h.config.HPrefix,
+		"address", h.config.Options.Addr,
+		"username", h.config.Options.Username,
+		"password-len", len(h.config.Options.Password),
+		"db", h.config.Options.DB,
+	)
+
+	h.db = redis.NewClient(h.config.Options)
+	_, err := h.db.Ping(context.Background()).Result()
+	if err != nil {
+		return fmt.Errorf("failed to ping service: %w", err)
+	}
+
+	h.Log.Info("connected to redis service")
+
+	return nil
+}
+
+// Stop closes the redis connection.
+func (h *Hook) Stop() error {
+	h.Log.Info("disconnecting from redis service")
+
+	return h.db.Close()
+}
+
+// OnSessionEstablished adds a client to the store when their session is established.
+func (h *Hook) OnSessionEstablished(cl *mqtt.Client, pk packets.Packet) {
+	h.updateClient(cl)
+}
+
+// OnWillSent is called when a client sends a Will Message and the Will Message is removed from the client record.
+func (h *Hook) OnWillSent(cl *mqtt.Client, pk packets.Packet) {
+	h.updateClient(cl)
+}
+
+// updateClient writes the client data to the store.
+func (h *Hook) updateClient(cl *mqtt.Client) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	props := cl.Properties.Props.Copy(false)
+	in := &storage.Client{
+		ID:              clientKey(cl),
+		T:               storage.ClientKey,
+		Remote:          cl.Net.Remote,
+		Listener:        cl.Net.Listener,
+		Username:        cl.Properties.Username,
+		Clean:           cl.Properties.Clean,
+		ProtocolVersion: cl.Properties.ProtocolVersion,
+		Properties: storage.ClientProperties{
+			SessionExpiryInterval: props.SessionExpiryInterval,
+			AuthenticationMethod:  props.AuthenticationMethod,
+			AuthenticationData:    props.AuthenticationData,
+			RequestProblemInfo:    props.RequestProblemInfo,
+			RequestResponseInfo:   props.RequestResponseInfo,
+			ReceiveMaximum:        props.ReceiveMaximum,
+			TopicAliasMaximum:     props.TopicAliasMaximum,
+			User:                  props.User,
+			MaximumPacketSize:     props.MaximumPacketSize,
+		},
+		Will: storage.ClientWill(cl.Properties.Will),
+	}
+
+	err := h.db.HSet(h.ctx, h.hKey(storage.ClientKey), clientKey(cl), in).Err()
+	if err != nil {
+		h.Log.Error("failed to hset client data", "error", err, "data", in)
+	}
+}
+
+// OnDisconnect removes a client from the store if they were using a clean session.
+func (h *Hook) OnDisconnect(cl *mqtt.Client, _ error, expire bool) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	if !expire {
+		return
+	}
+
+	if cl.StopCause() == packets.ErrSessionTakenOver {
+		return
+	}
+
+	err := h.db.HDel(h.ctx, h.hKey(storage.ClientKey), clientKey(cl)).Err()
+	if err != nil {
+		h.Log.Error("failed to delete client", "error", err, "id", clientKey(cl))
+	}
+}
+
+// OnSubscribed adds one or more client subscriptions to the store.
+func (h *Hook) OnSubscribed(cl *mqtt.Client, pk packets.Packet, reasonCodes []byte) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	var in *storage.Subscription
+	for i := 0; i < len(pk.Filters); i++ {
+		in = &storage.Subscription{
+			ID:                subscriptionKey(cl, pk.Filters[i].Filter),
+			T:                 storage.SubscriptionKey,
+			Client:            cl.ID,
+			Qos:               reasonCodes[i],
+			Filter:            pk.Filters[i].Filter,
+			Identifier:        pk.Filters[i].Identifier,
+			NoLocal:           pk.Filters[i].NoLocal,
+			RetainHandling:    pk.Filters[i].RetainHandling,
+			RetainAsPublished: pk.Filters[i].RetainAsPublished,
+		}
+
+		err := h.db.HSet(h.ctx, h.hKey(storage.SubscriptionKey), subscriptionKey(cl, pk.Filters[i].Filter), in).Err()
+		if err != nil {
+			h.Log.Error("failed to hset subscription data", "error", err, "data", in)
+		}
+	}
+}
+
+// OnUnsubscribed removes one or more client subscriptions from the store.
+func (h *Hook) OnUnsubscribed(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	for i := 0; i < len(pk.Filters); i++ {
+		err := h.db.HDel(h.ctx, h.hKey(storage.SubscriptionKey), subscriptionKey(cl, pk.Filters[i].Filter)).Err()
+		if err != nil {
+			h.Log.Error("failed to delete subscription data", "error", err, "id", clientKey(cl))
+		}
+	}
+}
+
+// OnRetainMessage adds a retained message for a topic to the store.
+func (h *Hook) OnRetainMessage(cl *mqtt.Client, pk packets.Packet, r int64) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	if r == -1 {
+		err := h.db.HDel(h.ctx, h.hKey(storage.RetainedKey), retainedKey(pk.TopicName)).Err()
+		if err != nil {
+			h.Log.Error("failed to delete retained message data", "error", err, "id", retainedKey(pk.TopicName))
+		}
+
+		return
+	}
+
+	props := pk.Properties.Copy(false)
+	in := &storage.Message{
+		ID:          retainedKey(pk.TopicName),
+		T:           storage.RetainedKey,
+		FixedHeader: pk.FixedHeader,
+		TopicName:   pk.TopicName,
+		Payload:     pk.Payload,
+		Created:     pk.Created,
+		Origin:      pk.Origin,
+		Properties: storage.MessageProperties{
+			PayloadFormat:          props.PayloadFormat,
+			MessageExpiryInterval:  props.MessageExpiryInterval,
+			ContentType:            props.ContentType,
+			ResponseTopic:          props.ResponseTopic,
+			CorrelationData:        props.CorrelationData,
+			SubscriptionIdentifier: props.SubscriptionIdentifier,
+			TopicAlias:             props.TopicAlias,
+			User:                   props.User,
+		},
+	}
+
+	err := h.db.HSet(h.ctx, h.hKey(storage.RetainedKey), retainedKey(pk.TopicName), in).Err()
+	if err != nil {
+		h.Log.Error("failed to hset retained message data", "error", err, "data", in)
+	}
+}
+
+// OnQosPublish adds or updates an inflight message in the store.
+func (h *Hook) OnQosPublish(cl *mqtt.Client, pk packets.Packet, sent int64, resends int) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	props := pk.Properties.Copy(false)
+	in := &storage.Message{
+		ID:          inflightKey(cl, pk),
+		T:           storage.InflightKey,
+		Origin:      pk.Origin,
+		FixedHeader: pk.FixedHeader,
+		TopicName:   pk.TopicName,
+		Payload:     pk.Payload,
+		Sent:        sent,
+		Created:     pk.Created,
+		Properties: storage.MessageProperties{
+			PayloadFormat:          props.PayloadFormat,
+			MessageExpiryInterval:  props.MessageExpiryInterval,
+			ContentType:            props.ContentType,
+			ResponseTopic:          props.ResponseTopic,
+			CorrelationData:        props.CorrelationData,
+			SubscriptionIdentifier: props.SubscriptionIdentifier,
+			TopicAlias:             props.TopicAlias,
+			User:                   props.User,
+		},
+	}
+
+	err := h.db.HSet(h.ctx, h.hKey(storage.InflightKey), inflightKey(cl, pk), in).Err()
+	if err != nil {
+		h.Log.Error("failed to hset qos inflight message data", "error", err, "data", in)
+	}
+}
+
+// OnQosComplete removes a resolved inflight message from the store.
+func (h *Hook) OnQosComplete(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	err := h.db.HDel(h.ctx, h.hKey(storage.InflightKey), inflightKey(cl, pk)).Err()
+	if err != nil {
+		h.Log.Error("failed to delete qos inflight message data", "error", err, "id", inflightKey(cl, pk))
+	}
+}
+
+// OnQosDropped removes a dropped inflight message from the store.
+func (h *Hook) OnQosDropped(cl *mqtt.Client, pk packets.Packet) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+	}
+
+	h.OnQosComplete(cl, pk)
+}
+
+// OnSysInfoTick stores the latest system info in the store.
+func (h *Hook) OnSysInfoTick(sys *system.Info) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	in := &storage.SystemInfo{
+		ID:   sysInfoKey(),
+		T:    storage.SysInfoKey,
+		Info: *sys,
+	}
+
+	err := h.db.HSet(h.ctx, h.hKey(storage.SysInfoKey), sysInfoKey(), in).Err()
+	if err != nil {
+		h.Log.Error("failed to hset server info data", "error", err, "data", in)
+	}
+}
+
+// OnRetainedExpired deletes expired retained messages from the store.
+func (h *Hook) OnRetainedExpired(filter string) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	err := h.db.HDel(h.ctx, h.hKey(storage.RetainedKey), retainedKey(filter)).Err()
+	if err != nil {
+		h.Log.Error("failed to delete expired retained message", "error", err, "id", retainedKey(filter))
+	}
+}
+
+// OnClientExpired deleted expired clients from the store.
+func (h *Hook) OnClientExpired(cl *mqtt.Client) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	err := h.db.HDel(h.ctx, h.hKey(storage.ClientKey), clientKey(cl)).Err()
+	if err != nil {
+		h.Log.Error("failed to delete expired client", "error", err, "id", clientKey(cl))
+	}
+}
+
+// StoredClients returns all stored clients from the store.
+func (h *Hook) StoredClients() (v []storage.Client, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	rows, err := h.db.HGetAll(h.ctx, h.hKey(storage.ClientKey)).Result()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		h.Log.Error("failed to HGetAll client data", "error", err)
+		return
+	}
+
+	for _, row := range rows {
+		var d storage.Client
+		if err = d.UnmarshalBinary([]byte(row)); err != nil {
+			h.Log.Error("failed to unmarshal client data", "error", err, "data", row)
+		}
+
+		v = append(v, d)
+	}
+
+	return v, nil
+}
+
+// StoredSubscriptions returns all stored subscriptions from the store.
+func (h *Hook) StoredSubscriptions() (v []storage.Subscription, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	rows, err := h.db.HGetAll(h.ctx, h.hKey(storage.SubscriptionKey)).Result()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		h.Log.Error("failed to HGetAll subscription data", "error", err)
+		return
+	}
+
+	for _, row := range rows {
+		var d storage.Subscription
+		if err = d.UnmarshalBinary([]byte(row)); err != nil {
+			h.Log.Error("failed to unmarshal subscription data", "error", err, "data", row)
+		}
+
+		v = append(v, d)
+	}
+
+	return v, nil
+}
+
+// StoredRetainedMessages returns all stored retained messages from the store.
+func (h *Hook) StoredRetainedMessages() (v []storage.Message, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	rows, err := h.db.HGetAll(h.ctx, h.hKey(storage.RetainedKey)).Result()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		h.Log.Error("failed to HGetAll retained message data", "error", err)
+		return
+	}
+
+	for _, row := range rows {
+		var d storage.Message
+		if err = d.UnmarshalBinary([]byte(row)); err != nil {
+			h.Log.Error("failed to unmarshal retained message data", "error", err, "data", row)
+		}
+
+		v = append(v, d)
+	}
+
+	return v, nil
+}
+
+// StoredInflightMessages returns all stored inflight messages from the store.
+func (h *Hook) StoredInflightMessages() (v []storage.Message, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	rows, err := h.db.HGetAll(h.ctx, h.hKey(storage.InflightKey)).Result()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		h.Log.Error("failed to HGetAll inflight message data", "error", err)
+		return
+	}
+
+	for _, row := range rows {
+		var d storage.Message
+		if err = d.UnmarshalBinary([]byte(row)); err != nil {
+			h.Log.Error("failed to unmarshal inflight message data", "error", err, "data", row)
+		}
+
+		v = append(v, d)
+	}
+
+	return v, nil
+}
+
+// StoredSysInfo returns the system info from the store.
+func (h *Hook) StoredSysInfo() (v storage.SystemInfo, err error) {
+	if h.db == nil {
+		h.Log.Error("", "error", storage.ErrDBFileNotOpen)
+		return
+	}
+
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.SysInfoKey), storage.SysInfoKey).Result()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		return
+	}
+
+	if err = v.UnmarshalBinary([]byte(row)); err != nil {
+		h.Log.Error("failed to unmarshal sys info data", "error", err, "data", row)
+	}
+
+	return v, nil
+}

hooks/storage/redis/redis_test.go

@@ -0,0 +1,834 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: mochi-co
+
+package redis
+
+import (
+	"log/slog"
+	"os"
+	"sort"
+	"testing"
+	"time"
+
+	"testmqtt/hooks/storage"
+	"testmqtt/mqtt"
+	"testmqtt/packets"
+	"testmqtt/system"
+
+	miniredis "github.com/alicebob/miniredis/v2"
+	redis "github.com/go-redis/redis/v8"
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	logger = slog.New(slog.NewTextHandler(os.Stdout, nil))
+
+	client = &mqtt.Client{
+		ID: "test",
+		Net: mqtt.ClientConnection{
+			Remote:   "test.addr",
+			Listener: "listener",
+		},
+		Properties: mqtt.ClientProperties{
+			Username: []byte("username"),
+			Clean:    false,
+		},
+	}
+
+	pkf = packets.Packet{Filters: packets.Subscriptions{{Filter: "a/b/c"}}}
+)
+
+func newHook(t *testing.T, addr string) *Hook {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(&Options{
+		Options: &redis.Options{
+			Addr: addr,
+		},
+	})
+	require.NoError(t, err)
+
+	return h
+}
+
+func teardown(t *testing.T, h *Hook) {
+	if h.db != nil {
+		err := h.db.FlushAll(h.ctx).Err()
+		require.NoError(t, err)
+		h.Stop()
+	}
+}
+
+func TestClientKey(t *testing.T) {
+	k := clientKey(&mqtt.Client{ID: "cl1"})
+	require.Equal(t, "cl1", k)
+}
+
+func TestSubscriptionKey(t *testing.T) {
+	k := subscriptionKey(&mqtt.Client{ID: "cl1"}, "a/b/c")
+	require.Equal(t, "cl1:a/b/c", k)
+}
+
+func TestRetainedKey(t *testing.T) {
+	k := retainedKey("a/b/c")
+	require.Equal(t, "a/b/c", k)
+}
+
+func TestInflightKey(t *testing.T) {
+	k := inflightKey(&mqtt.Client{ID: "cl1"}, packets.Packet{PacketID: 1})
+	require.Equal(t, "cl1:1", k)
+}
+
+func TestSysInfoKey(t *testing.T) {
+	require.Equal(t, storage.SysInfoKey, sysInfoKey())
+}
+
+func TestID(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	require.Equal(t, "redis-db", h.ID())
+}
+
+func TestProvides(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	require.True(t, h.Provides(mqtt.OnSessionEstablished))
+	require.True(t, h.Provides(mqtt.OnDisconnect))
+	require.True(t, h.Provides(mqtt.OnSubscribed))
+	require.True(t, h.Provides(mqtt.OnUnsubscribed))
+	require.True(t, h.Provides(mqtt.OnRetainMessage))
+	require.True(t, h.Provides(mqtt.OnQosPublish))
+	require.True(t, h.Provides(mqtt.OnQosComplete))
+	require.True(t, h.Provides(mqtt.OnQosDropped))
+	require.True(t, h.Provides(mqtt.OnSysInfoTick))
+	require.True(t, h.Provides(mqtt.StoredClients))
+	require.True(t, h.Provides(mqtt.StoredInflightMessages))
+	require.True(t, h.Provides(mqtt.StoredRetainedMessages))
+	require.True(t, h.Provides(mqtt.StoredSubscriptions))
+	require.True(t, h.Provides(mqtt.StoredSysInfo))
+	require.False(t, h.Provides(mqtt.OnACLCheck))
+	require.False(t, h.Provides(mqtt.OnConnectAuthenticate))
+}
+
+func TestHKey(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.SetOpts(logger, nil)
+	require.Equal(t, defaultHPrefix+"test", h.hKey("test"))
+}
+
+func TestInitUseDefaults(t *testing.T) {
+	s := miniredis.RunT(t)
+	s.StartAddr(defaultAddr)
+	defer s.Close()
+
+	h := newHook(t, defaultAddr)
+	h.SetOpts(logger, nil)
+	err := h.Init(nil)
+	require.NoError(t, err)
+	defer teardown(t, h)
+
+	require.Equal(t, defaultHPrefix, h.config.HPrefix)
+	require.Equal(t, defaultAddr, h.config.Options.Addr)
+}
+
+func TestInitUsePassConfig(t *testing.T) {
+	s := miniredis.RunT(t)
+	s.StartAddr(defaultAddr)
+	defer s.Close()
+
+	h := newHook(t, "")
+	h.SetOpts(logger, nil)
+
+	err := h.Init(&Options{
+		Address:  defaultAddr,
+		Username: "username",
+		Password: "password",
+		Database: 2,
+	})
+	require.Error(t, err)
+	h.db.FlushAll(h.ctx)
+
+	require.Equal(t, defaultAddr, h.config.Options.Addr)
+	require.Equal(t, "username", h.config.Options.Username)
+	require.Equal(t, "password", h.config.Options.Password)
+	require.Equal(t, 2, h.config.Options.DB)
+}
+
+func TestInitBadConfig(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+
+	err := h.Init(map[string]any{})
+	require.Error(t, err)
+}
+
+func TestInitBadAddr(t *testing.T) {
+	h := new(Hook)
+	h.SetOpts(logger, nil)
+	err := h.Init(&Options{
+		Options: &redis.Options{
+			Addr: "abc:123",
+		},
+	})
+	require.Error(t, err)
+}
+
+func TestOnSessionEstablishedThenOnDisconnect(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	h.OnSessionEstablished(client, packets.Packet{})
+
+	r := new(storage.Client)
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.ClientKey), clientKey(client)).Result()
+	require.NoError(t, err)
+	err = r.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+
+	require.Equal(t, client.ID, r.ID)
+	require.Equal(t, client.Net.Remote, r.Remote)
+	require.Equal(t, client.Net.Listener, r.Listener)
+	require.Equal(t, client.Properties.Username, r.Username)
+	require.Equal(t, client.Properties.Clean, r.Clean)
+	require.NotSame(t, client, r)
+
+	h.OnDisconnect(client, nil, false)
+	r2 := new(storage.Client)
+	row, err = h.db.HGet(h.ctx, h.hKey(storage.ClientKey), clientKey(client)).Result()
+	require.NoError(t, err)
+	err = r2.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.ID)
+
+	h.OnDisconnect(client, nil, true)
+	r3 := new(storage.Client)
+	_, err = h.db.HGet(h.ctx, h.hKey(storage.ClientKey), clientKey(client)).Result()
+	require.Error(t, err)
+	require.ErrorIs(t, err, redis.Nil)
+	require.Empty(t, r3.ID)
+}
+
+func TestOnSessionEstablishedNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+
+	h.db = nil
+	h.OnSessionEstablished(client, packets.Packet{})
+}
+
+func TestOnSessionEstablishedClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnSessionEstablished(client, packets.Packet{})
+}
+
+func TestOnWillSent(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	c1 := client
+	c1.Properties.Will.Flag = 1
+	h.OnWillSent(c1, packets.Packet{})
+
+	r := new(storage.Client)
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.ClientKey), clientKey(client)).Result()
+	require.NoError(t, err)
+	err = r.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+
+	require.Equal(t, uint32(1), r.Will.Flag)
+	require.NotSame(t, client, r)
+}
+
+func TestOnClientExpired(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	cl := &mqtt.Client{ID: "cl1"}
+	clientKey := clientKey(cl)
+
+	err := h.db.HSet(h.ctx, h.hKey(storage.ClientKey), clientKey, &storage.Client{ID: cl.ID}).Err()
+	require.NoError(t, err)
+
+	r := new(storage.Client)
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.ClientKey), clientKey).Result()
+	require.NoError(t, err)
+	err = r.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+	require.Equal(t, clientKey, r.ID)
+
+	h.OnClientExpired(cl)
+	_, err = h.db.HGet(h.ctx, h.hKey(storage.ClientKey), clientKey).Result()
+	require.Error(t, err)
+	require.ErrorIs(t, redis.Nil, err)
+}
+
+func TestOnClientExpiredClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnClientExpired(client)
+}
+
+func TestOnClientExpiredNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnClientExpired(client)
+}
+
+func TestOnDisconnectNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnDisconnect(client, nil, false)
+}
+
+func TestOnDisconnectClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnDisconnect(client, nil, false)
+}
+
+func TestOnDisconnectSessionTakenOver(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+
+	testClient := &mqtt.Client{
+		ID: "test",
+		Net: mqtt.ClientConnection{
+			Remote:   "test.addr",
+			Listener: "listener",
+		},
+		Properties: mqtt.ClientProperties{
+			Username: []byte("username"),
+			Clean:    false,
+		},
+	}
+
+	testClient.Stop(packets.ErrSessionTakenOver)
+	teardown(t, h)
+	h.OnDisconnect(testClient, nil, true)
+}
+
+func TestOnSubscribedThenOnUnsubscribed(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	h.OnSubscribed(client, pkf, []byte{0})
+
+	r := new(storage.Subscription)
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.SubscriptionKey), subscriptionKey(client, pkf.Filters[0].Filter)).Result()
+	require.NoError(t, err)
+	err = r.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+	require.Equal(t, client.ID, r.Client)
+	require.Equal(t, pkf.Filters[0].Filter, r.Filter)
+	require.Equal(t, byte(0), r.Qos)
+
+	h.OnUnsubscribed(client, pkf)
+	_, err = h.db.HGet(h.ctx, h.hKey(storage.SubscriptionKey), subscriptionKey(client, pkf.Filters[0].Filter)).Result()
+	require.Error(t, err)
+	require.ErrorIs(t, err, redis.Nil)
+}
+
+func TestOnSubscribedNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnSubscribed(client, pkf, []byte{0})
+}
+
+func TestOnSubscribedClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnSubscribed(client, pkf, []byte{0})
+}
+
+func TestOnUnsubscribedNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnUnsubscribed(client, pkf)
+}
+
+func TestOnUnsubscribedClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnUnsubscribed(client, pkf)
+}
+
+func TestOnRetainMessageThenUnset(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	pk := packets.Packet{
+		FixedHeader: packets.FixedHeader{
+			Retain: true,
+		},
+		Payload:   []byte("hello"),
+		TopicName: "a/b/c",
+	}
+
+	h.OnRetainMessage(client, pk, 1)
+
+	r := new(storage.Message)
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.RetainedKey), retainedKey(pk.TopicName)).Result()
+	require.NoError(t, err)
+	err = r.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+
+	require.NoError(t, err)
+	require.Equal(t, pk.TopicName, r.TopicName)
+	require.Equal(t, pk.Payload, r.Payload)
+
+	h.OnRetainMessage(client, pk, -1)
+	_, err = h.db.HGet(h.ctx, h.hKey(storage.RetainedKey), retainedKey(pk.TopicName)).Result()
+	require.Error(t, err)
+	require.ErrorIs(t, err, redis.Nil)
+
+	// coverage: delete deleted
+	h.OnRetainMessage(client, pk, -1)
+	_, err = h.db.HGet(h.ctx, h.hKey(storage.RetainedKey), retainedKey(pk.TopicName)).Result()
+	require.Error(t, err)
+	require.ErrorIs(t, err, redis.Nil)
+}
+
+func TestOnRetainedExpired(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	m := &storage.Message{
+		ID:        retainedKey("a/b/c"),
+		T:         storage.RetainedKey,
+		TopicName: "a/b/c",
+	}
+
+	err := h.db.HSet(h.ctx, h.hKey(storage.RetainedKey), m.ID, m).Err()
+	require.NoError(t, err)
+
+	r := new(storage.Message)
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.RetainedKey), m.ID).Result()
+	require.NoError(t, err)
+	err = r.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+	require.NoError(t, err)
+	require.Equal(t, m.TopicName, r.TopicName)
+
+	h.OnRetainedExpired(m.TopicName)
+
+	_, err = h.db.HGet(h.ctx, h.hKey(storage.RetainedKey), m.ID).Result()
+	require.Error(t, err)
+	require.ErrorIs(t, err, redis.Nil)
+}
+
+func TestOnRetainedExpiredClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnRetainedExpired("a/b/c")
+}
+
+func TestOnRetainedExpiredNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnRetainedExpired("a/b/c")
+}
+
+func TestOnRetainMessageNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnRetainMessage(client, packets.Packet{}, 0)
+}
+
+func TestOnRetainMessageClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnRetainMessage(client, packets.Packet{}, 0)
+}
+
+func TestOnQosPublishThenQOSComplete(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	pk := packets.Packet{
+		FixedHeader: packets.FixedHeader{
+			Retain: true,
+			Qos:    2,
+		},
+		Payload:   []byte("hello"),
+		TopicName: "a/b/c",
+	}
+
+	h.OnQosPublish(client, pk, time.Now().Unix(), 0)
+
+	r := new(storage.Message)
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.InflightKey), inflightKey(client, pk)).Result()
+	require.NoError(t, err)
+	err = r.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+	require.Equal(t, pk.TopicName, r.TopicName)
+	require.Equal(t, pk.Payload, r.Payload)
+
+	// ensure dates are properly saved to bolt
+	require.True(t, r.Sent > 0)
+	require.True(t, time.Now().Unix()-1 < r.Sent)
+
+	// OnQosDropped is a passthrough to OnQosComplete here
+	h.OnQosDropped(client, pk)
+	_, err = h.db.HGet(h.ctx, h.hKey(storage.InflightKey), inflightKey(client, pk)).Result()
+	require.Error(t, err)
+	require.ErrorIs(t, err, redis.Nil)
+}
+
+func TestOnQosPublishNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnQosPublish(client, packets.Packet{}, time.Now().Unix(), 0)
+}
+
+func TestOnQosPublishClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnQosPublish(client, packets.Packet{}, time.Now().Unix(), 0)
+}
+
+func TestOnQosCompleteNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnQosComplete(client, packets.Packet{})
+}
+
+func TestOnQosCompleteClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnQosComplete(client, packets.Packet{})
+}
+
+func TestOnQosDroppedNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnQosDropped(client, packets.Packet{})
+}
+
+func TestOnSysInfoTick(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	info := &system.Info{
+		Version:       "2.0.0",
+		BytesReceived: 100,
+	}
+
+	h.OnSysInfoTick(info)
+
+	r := new(storage.SystemInfo)
+	row, err := h.db.HGet(h.ctx, h.hKey(storage.SysInfoKey), storage.SysInfoKey).Result()
+	require.NoError(t, err)
+	err = r.UnmarshalBinary([]byte(row))
+	require.NoError(t, err)
+	require.Equal(t, info.Version, r.Version)
+	require.Equal(t, info.BytesReceived, r.BytesReceived)
+	require.NotSame(t, info, r)
+}
+
+func TestOnSysInfoTickClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+	h.OnSysInfoTick(new(system.Info))
+}
+func TestOnSysInfoTickNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	h.OnSysInfoTick(new(system.Info))
+}
+
+func TestStoredClients(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	// populate with clients
+	err := h.db.HSet(h.ctx, h.hKey(storage.ClientKey), "cl1", &storage.Client{ID: "cl1", T: storage.ClientKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.ClientKey), "cl2", &storage.Client{ID: "cl2", T: storage.ClientKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.ClientKey), "cl3", &storage.Client{ID: "cl3", T: storage.ClientKey}).Err()
+	require.NoError(t, err)
+
+	r, err := h.StoredClients()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+
+	sort.Slice(r[:], func(i, j int) bool { return r[i].ID < r[j].ID })
+	require.Equal(t, "cl1", r[0].ID)
+	require.Equal(t, "cl2", r[1].ID)
+	require.Equal(t, "cl3", r[2].ID)
+}
+
+func TestStoredClientsNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	v, err := h.StoredClients()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredClientsClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+
+	v, err := h.StoredClients()
+	require.Empty(t, v)
+	require.Error(t, err)
+}
+
+func TestStoredSubscriptions(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	// populate with subscriptions
+	err := h.db.HSet(h.ctx, h.hKey(storage.SubscriptionKey), "sub1", &storage.Subscription{ID: "sub1", T: storage.SubscriptionKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.SubscriptionKey), "sub2", &storage.Subscription{ID: "sub2", T: storage.SubscriptionKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.SubscriptionKey), "sub3", &storage.Subscription{ID: "sub3", T: storage.SubscriptionKey}).Err()
+	require.NoError(t, err)
+
+	r, err := h.StoredSubscriptions()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	sort.Slice(r[:], func(i, j int) bool { return r[i].ID < r[j].ID })
+	require.Equal(t, "sub1", r[0].ID)
+	require.Equal(t, "sub2", r[1].ID)
+	require.Equal(t, "sub3", r[2].ID)
+}
+
+func TestStoredSubscriptionsNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	v, err := h.StoredSubscriptions()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredSubscriptionsClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+
+	v, err := h.StoredSubscriptions()
+	require.Empty(t, v)
+	require.Error(t, err)
+}
+
+func TestStoredRetainedMessages(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	// populate with messages
+	err := h.db.HSet(h.ctx, h.hKey(storage.RetainedKey), "m1", &storage.Message{ID: "m1", T: storage.RetainedKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.RetainedKey), "m2", &storage.Message{ID: "m2", T: storage.RetainedKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.RetainedKey), "m3", &storage.Message{ID: "m3", T: storage.RetainedKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.InflightKey), "i3", &storage.Message{ID: "i3", T: storage.InflightKey}).Err()
+	require.NoError(t, err)
+
+	r, err := h.StoredRetainedMessages()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	sort.Slice(r[:], func(i, j int) bool { return r[i].ID < r[j].ID })
+	require.Equal(t, "m1", r[0].ID)
+	require.Equal(t, "m2", r[1].ID)
+	require.Equal(t, "m3", r[2].ID)
+}
+
+func TestStoredRetainedMessagesNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	v, err := h.StoredRetainedMessages()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredRetainedMessagesClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+
+	v, err := h.StoredRetainedMessages()
+	require.Empty(t, v)
+	require.Error(t, err)
+}
+
+func TestStoredInflightMessages(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	// populate with messages
+	err := h.db.HSet(h.ctx, h.hKey(storage.InflightKey), "i1", &storage.Message{ID: "i1", T: storage.InflightKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.InflightKey), "i2", &storage.Message{ID: "i2", T: storage.InflightKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.InflightKey), "i3", &storage.Message{ID: "i3", T: storage.InflightKey}).Err()
+	require.NoError(t, err)
+
+	err = h.db.HSet(h.ctx, h.hKey(storage.RetainedKey), "m3", &storage.Message{ID: "m3", T: storage.RetainedKey}).Err()
+	require.NoError(t, err)
+
+	r, err := h.StoredInflightMessages()
+	require.NoError(t, err)
+	require.Len(t, r, 3)
+	sort.Slice(r[:], func(i, j int) bool { return r[i].ID < r[j].ID })
+	require.Equal(t, "i1", r[0].ID)
+	require.Equal(t, "i2", r[1].ID)
+	require.Equal(t, "i3", r[2].ID)
+}
+
+func TestStoredInflightMessagesNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	v, err := h.StoredInflightMessages()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredInflightMessagesClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+
+	v, err := h.StoredInflightMessages()
+	require.Empty(t, v)
+	require.Error(t, err)
+}
+
+func TestStoredSysInfo(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	defer teardown(t, h)
+
+	// populate with sys info
+	err := h.db.HSet(h.ctx, h.hKey(storage.SysInfoKey), storage.SysInfoKey,
+		&storage.SystemInfo{
+			ID: storage.SysInfoKey,
+			Info: system.Info{
+				Version: "2.0.0",
+			},
+			T: storage.SysInfoKey,
+		}).Err()
+	require.NoError(t, err)
+
+	r, err := h.StoredSysInfo()
+	require.NoError(t, err)
+	require.Equal(t, "2.0.0", r.Info.Version)
+}
+
+func TestStoredSysInfoNoDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	h.db = nil
+	v, err := h.StoredSysInfo()
+	require.Empty(t, v)
+	require.NoError(t, err)
+}
+
+func TestStoredSysInfoClosedDB(t *testing.T) {
+	s := miniredis.RunT(t)
+	defer s.Close()
+	h := newHook(t, s.Addr())
+	teardown(t, h)
+
+	v, err := h.StoredSysInfo()
+	require.Empty(t, v)
+	require.Error(t, err)
+}

hooks/storage/storage.go

@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: mochi-co
+
+package storage
+
+import (
+	"encoding/json"
+	"errors"
+
+	"testmqtt/packets"
+	"testmqtt/system"
+)
+
+const (
+	// SubscriptionKey 唯一标识订阅信息。在存储系统中，这个键用于检索和管理客户端的订阅信息
+	// SubscriptionKey unique key to denote Subscriptions in a store
+	SubscriptionKey = "SUB"
+	// SysInfoKey 唯一标识服务器系统信息。在存储系统中，这个键用于存储和检索与服务器状态或系统配置相关的信息。
+	// SysInfoKey unique key to denote server system information in a store
+	SysInfoKey = "SYS"
+	// RetainedKey 唯一标识保留的消息。保留消息是在订阅时立即发送的消息，即使订阅者在消息发布时不在线。这个键用于存储这些保留消息。
+	// RetainedKey unique key to denote retained messages in a store
+	RetainedKey = "RET"
+	// InflightKey 唯一标识飞行中的消息。飞行中的消息指的是已经发布但尚未确认的消息，这个键用于跟踪这些消息的状态。
+	// InflightKey unique key to denote inflight messages in a store
+	InflightKey = "IFM"
+	// ClientKey 唯一标识客户端信息。在存储系统中，这个键用于检索和管理有关客户端的信息，如客户端状态、连接信息等。
+	// ClientKey unique key to denote clients in a store
+	ClientKey = "CL"
+)
+
+var (
+	// ErrDBFileNotOpen 数据库文件没有打开
+	// ErrDBFileNotOpen indicates that the file database (e.g. bolt/badger) wasn't open for reading.
+	ErrDBFileNotOpen = errors.New("数据库文件没有打开")
+)
+
+// Serializable is an interface for objects that can be serialized and deserialized.
+type Serializable interface {
+	UnmarshalBinary([]byte) error
+	MarshalBinary() (data []byte, err error)
+}
+
+// Client is a storable representation of an MQTT client.
+type Client struct {
+	Will            ClientWill       `json:"will"`            // will topic and payload data if applicable
+	Properties      ClientProperties `json:"properties"`      // the connect properties for the client
+	Username        []byte           `json:"username"`        // the username of the client
+	ID              string           `json:"id" storm:"id"`   // the client id / storage key
+	T               string           `json:"t"`               // the data type (client)
+	Remote          string           `json:"remote"`          // the remote address of the client
+	Listener        string           `json:"listener"`        // the listener the client connected on
+	ProtocolVersion byte             `json:"protocolVersion"` // mqtt protocol version of the client
+	Clean           bool             `json:"clean"`           // if the client requested a clean start/session
+}
+
+// ClientProperties contains a limited set of the mqtt v5 properties specific to a client connection.
+type ClientProperties struct {
+	AuthenticationData        []byte                 `json:"authenticationData,omitempty"`
+	User                      []packets.UserProperty `json:"user,omitempty"`
+	AuthenticationMethod      string                 `json:"authenticationMethod,omitempty"`
+	SessionExpiryInterval     uint32                 `json:"sessionExpiryInterval,omitempty"`
+	MaximumPacketSize         uint32                 `json:"maximumPacketSize,omitempty"`
+	ReceiveMaximum            uint16                 `json:"receiveMaximum,omitempty"`
+	TopicAliasMaximum         uint16                 `json:"topicAliasMaximum,omitempty"`
+	SessionExpiryIntervalFlag bool                   `json:"sessionExpiryIntervalFlag,omitempty"`
+	RequestProblemInfo        byte                   `json:"requestProblemInfo,omitempty"`
+	RequestProblemInfoFlag    bool                   `json:"requestProblemInfoFlag,omitempty"`
+	RequestResponseInfo       byte                   `json:"requestResponseInfo,omitempty"`
+}
+
+// ClientWill contains a will message for a client, and limited mqtt v5 properties.
+type ClientWill struct {
+	Payload           []byte                 `json:"payload,omitempty"`
+	User              []packets.UserProperty `json:"user,omitempty"`
+	TopicName         string                 `json:"topicName,omitempty"`
+	Flag              uint32                 `json:"flag,omitempty"`
+	WillDelayInterval uint32                 `json:"willDelayInterval,omitempty"`
+	Qos               byte                   `json:"qos,omitempty"`
+	Retain            bool                   `json:"retain,omitempty"`
+}
+
+// MarshalBinary encodes the values into a json string.
+func (d Client) MarshalBinary() (data []byte, err error) {
+	return json.Marshal(d)
+}
+
+// UnmarshalBinary decodes a json string into a struct.
+func (d *Client) UnmarshalBinary(data []byte) error {
+	if len(data) == 0 {
+		return nil
+	}
+	return json.Unmarshal(data, d)
+}
+
+// Message is a storable representation of an MQTT message (specifically publish).
+type Message struct {
+	Properties  MessageProperties   `json:"properties"`              // -
+	Payload     []byte              `json:"payload"`                 // the message payload (if retained)
+	T           string              `json:"t,omitempty"`             // the data type
+	ID          string              `json:"id,omitempty" storm:"id"` // the storage key
+	Origin      string              `json:"origin,omitempty"`        // the id of the client who sent the message
+	TopicName   string              `json:"topic_name,omitempty"`    // the topic the message was sent to (if retained)
+	FixedHeader packets.FixedHeader `json:"fixedheader"`             // the header properties of the message
+	Created     int64               `json:"created,omitempty"`       // the time the message was created in unixtime
+	Sent        int64               `json:"sent,omitempty"`          // the last time the message was sent (for retries) in unixtime (if inflight)
+	PacketID    uint16              `json:"packet_id,omitempty"`     // the unique id of the packet (if inflight)
+}
+
+// MessageProperties contains a limited subset of mqtt v5 properties specific to publish messages.
+type MessageProperties struct {
+	CorrelationData        []byte                 `json:"correlationData,omitempty"`
+	SubscriptionIdentifier []int                  `json:"subscriptionIdentifier,omitempty"`
+	User                   []packets.UserProperty `json:"user,omitempty"`
+	ContentType            string                 `json:"contentType,omitempty"`
+	ResponseTopic          string                 `json:"responseTopic,omitempty"`
+	MessageExpiryInterval  uint32                 `json:"messageExpiry,omitempty"`
+	TopicAlias             uint16                 `json:"topicAlias,omitempty"`
+	PayloadFormat          byte                   `json:"payloadFormat,omitempty"`
+	PayloadFormatFlag      bool                   `json:"payloadFormatFlag,omitempty"`
+}
+
+// MarshalBinary encodes the values into a json string.
+func (d Message) MarshalBinary() (data []byte, err error) {
+	return json.Marshal(d)
+}
+
+// UnmarshalBinary decodes a json string into a struct.
+func (d *Message) UnmarshalBinary(data []byte) error {
+	if len(data) == 0 {
+		return nil
+	}
+	return json.Unmarshal(data, d)
+}
+
+// ToPacket converts a storage.Message to a standard packet.
+func (d *Message) ToPacket() packets.Packet {
+	pk := packets.Packet{
+		FixedHeader: d.FixedHeader,
+		PacketID:    d.PacketID,
+		TopicName:   d.TopicName,
+		Payload:     d.Payload,
+		Origin:      d.Origin,
+		Created:     d.Created,
+		Properties: packets.Properties{
+			PayloadFormat:          d.Properties.PayloadFormat,
+			PayloadFormatFlag:      d.Properties.PayloadFormatFlag,
+			MessageExpiryInterval:  d.Properties.MessageExpiryInterval,
+			ContentType:            d.Properties.ContentType,
+			ResponseTopic:          d.Properties.ResponseTopic,
+			CorrelationData:        d.Properties.CorrelationData,
+			SubscriptionIdentifier: d.Properties.SubscriptionIdentifier,
+			TopicAlias:             d.Properties.TopicAlias,
+			User:                   d.Properties.User,
+		},
+	}
+
+	// Return a deep copy of the packet data otherwise the slices will
+	// continue pointing at the values from the storage packet.
+	pk = pk.Copy(true)
+	pk.FixedHeader.Dup = d.FixedHeader.Dup
+
+	return pk
+}
+
+// Subscription is a storable representation of an MQTT subscription.
+type Subscription struct {
+	T                 string `json:"t,omitempty"`
+	ID                string `json:"id,omitempty" storm:"id"`
+	Client            string `json:"client,omitempty"`
+	Filter            string `json:"filter"`
+	Identifier        int    `json:"identifier,omitempty"`
+	RetainHandling    byte   `json:"retain_handling,omitempty"`
+	Qos               byte   `json:"qos"`
+	RetainAsPublished bool   `json:"retain_as_pub,omitempty"`
+	NoLocal           bool   `json:"no_local,omitempty"`
+}
+
+// MarshalBinary encodes the values into a json string.
+func (d Subscription) MarshalBinary() (data []byte, err error) {
+	return json.Marshal(d)
+}
+
+// UnmarshalBinary decodes a json string into a struct.
+func (d *Subscription) UnmarshalBinary(data []byte) error {
+	if len(data) == 0 {
+		return nil
+	}
+	return json.Unmarshal(data, d)
+}
+
+// SystemInfo is a storable representation of the system information values.
+type SystemInfo struct {
+	system.Info        // embed the system info struct
+	T           string `json:"t"`             // the data type
+	ID          string `json:"id" storm:"id"` // the storage key
+}
+
+// MarshalBinary 将值编码为json字符串
+// MarshalBinary encodes the values into a json string.
+func (d SystemInfo) MarshalBinary() (data []byte, err error) {
+	return json.Marshal(d)
+}
+
+// UnmarshalBinary 将json字符串解码为结构体
+// UnmarshalBinary decodes a json string into a struct.
+func (d *SystemInfo) UnmarshalBinary(data []byte) error {
+	if len(data) == 0 {
+		return nil
+	}
+	return json.Unmarshal(data, d)
+}

hooks/storage/storage_test.go

@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
+// SPDX-FileContributor: mochi-co
+
+package storage
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"testmqtt/packets"
+	"testmqtt/system"
+)
+
+var (
+	clientStruct = Client{
+		ID:       "test",
+		T:        "client",
+		Remote:   "remote",
+		Listener: "listener",
+		Username: []byte("mochi"),
+		Clean:    true,
+		Properties: ClientProperties{
+			SessionExpiryInterval:     2,
+			SessionExpiryIntervalFlag: true,
+			AuthenticationMethod:      "a",
+			AuthenticationData:        []byte("test"),
+			RequestProblemInfo:        1,
+			RequestProblemInfoFlag:    true,
+			RequestResponseInfo:       1,
+			ReceiveMaximum:            128,
+			TopicAliasMaximum:         256,
+			User: []packets.UserProperty{
+				{Key: "k", Val: "v"},
+			},
+			MaximumPacketSize: 120,
+		},
+		Will: ClientWill{
+			Qos:               1,
+			Payload:           []byte("abc"),
+			TopicName:         "a/b/c",
+			Flag:              1,
+			Retain:            true,
+			WillDelayInterval: 2,
+			User: []packets.UserProperty{
+				{Key: "k2", Val: "v2"},
+			},
+		},
+	}
+	clientJSON = []byte(`{"will":{"payload":"YWJj","user":[{"k":"k2","v":"v2"}],"topicName":"a/b/c","flag":1,"willDelayInterval":2,"qos":1,"retain":true},"properties":{"authenticationData":"dGVzdA==","user":[{"k":"k","v":"v"}],"authenticationMethod":"a","sessionExpiryInterval":2,"maximumPacketSize":120,"receiveMaximum":128,"topicAliasMaximum":256,"sessionExpiryIntervalFlag":true,"requestProblemInfo":1,"requestProblemInfoFlag":true,"requestResponseInfo":1},"username":"bW9jaGk=","id":"test","t":"client","remote":"remote","listener":"listener","protocolVersion":0,"clean":true}`)
+
+	messageStruct = Message{
+		T:       "message",
+		Payload: []byte("payload"),
+		FixedHeader: packets.FixedHeader{
+			Remaining: 2,
+			Type:      3,
+			Qos:       1,
+			Dup:       true,
+			Retain:    true,
+		},
+		ID:        "id",
+		Origin:    "mochi",
+		TopicName: "topic",
+		Properties: MessageProperties{
+			PayloadFormat:          1,
+			PayloadFormatFlag:      true,
+			MessageExpiryInterval:  20,
+			ContentType:            "type",
+			ResponseTopic:          "a/b/r",
+			CorrelationData:        []byte("r"),
+			SubscriptionIdentifier: []int{1},
+			TopicAlias:             2,
+			User: []packets.UserProperty{
+				{Key: "k2", Val: "v2"},
+			},
+		},
+		Created:  time.Date(2019, time.September, 21, 1, 2, 3, 4, time.UTC).Unix(),
+		Sent:     time.Date(2019, time.September, 21, 1, 2, 3, 4, time.UTC).Unix(),
+		PacketID: 100,
+	}
+	messageJSON = []byte(`{"properties":{"correlationData":"cg==","subscriptionIdentifier":[1],"user":[{"k":"k2","v":"v2"}],"contentType":"type","responseTopic":"a/b/r","messageExpiry":20,"topicAlias":2,"payloadFormat":1,"payloadFormatFlag":true},"payload":"cGF5bG9hZA==","t":"message","id":"id","origin":"mochi","topic_name":"topic","fixedheader":{"remaining":2,"type":3,"qos":1,"dup":true,"retain":true},"created":1569027723,"sent":1569027723,"packet_id":100}`)
+
+	subscriptionStruct = Subscription{
+		T:      "subscription",
+		ID:     "id",
+		Client: "mochi",
+		Filter: "a/b/c",
+		Qos:    1,
+	}
+	subscriptionJSON = []byte(`{"t":"subscription","id":"id","client":"mochi","filter":"a/b/c","qos":1}`)
+
+	sysInfoStruct = SystemInfo{
+		T:  "info",
+		ID: "id",
+		Info: system.Info{
+			Version:          "2.0.0",
+			Started:          1,
+			Uptime:           2,
+			BytesReceived:    3,
+			BytesSent:        4,
+			ClientsConnected: 5,
+			ClientsMaximum:   7,
+			MessagesReceived: 10,
+			MessagesSent:     11,
+			MessagesDropped:  20,
+			PacketsReceived:  12,
+			PacketsSent:      13,
+			Retained:         15,
+			Inflight:         16,
+			InflightDropped:  17,
+		},
+	}
+	sysInfoJSON = []byte(`{"version":"2.0.0","started":1,"time":0,"uptime":2,"bytes_received":3,"bytes_sent":4,"clients_connected":5,"clients_disconnected":0,"clients_maximum":7,"clients_total":0,"messages_received":10,"messages_sent":11,"messages_dropped":20,"retained":15,"inflight":16,"inflight_dropped":17,"subscriptions":0,"packets_received":12,"packets_sent":13,"memory_alloc":0,"threads":0,"t":"info","id":"id"}`)
+)
+
+func TestClientMarshalBinary(t *testing.T) {
+	data, err := clientStruct.MarshalBinary()
+	require.NoError(t, err)
+	require.JSONEq(t, string(clientJSON), string(data))
+}
+
+func TestClientUnmarshalBinary(t *testing.T) {
+	d := clientStruct
+	err := d.UnmarshalBinary(clientJSON)
+	require.NoError(t, err)
+	require.Equal(t, clientStruct, d)
+}
+
+func TestClientUnmarshalBinaryEmpty(t *testing.T) {
+	d := Client{}
+	err := d.UnmarshalBinary([]byte{})
+	require.NoError(t, err)
+	require.Equal(t, Client{}, d)
+}
+
+func TestMessageMarshalBinary(t *testing.T) {
+	data, err := messageStruct.MarshalBinary()
+	require.NoError(t, err)
+	require.JSONEq(t, string(messageJSON), string(data))
+}
+
+func TestMessageUnmarshalBinary(t *testing.T) {
+	d := messageStruct
+	err := d.UnmarshalBinary(messageJSON)
+	require.NoError(t, err)
+	require.Equal(t, messageStruct, d)
+}
+
+func TestMessageUnmarshalBinaryEmpty(t *testing.T) {
+	d := Message{}
+	err := d.UnmarshalBinary([]byte{})
+	require.NoError(t, err)
+	require.Equal(t, Message{}, d)
+}
+
+func TestSubscriptionMarshalBinary(t *testing.T) {
+	data, err := subscriptionStruct.MarshalBinary()
+	require.NoError(t, err)
+	require.JSONEq(t, string(subscriptionJSON), string(data))
+}
+
+func TestSubscriptionUnmarshalBinary(t *testing.T) {
+	d := subscriptionStruct
+	err := d.UnmarshalBinary(subscriptionJSON)
+	require.NoError(t, err)
+	require.Equal(t, subscriptionStruct, d)
+}
+
+func TestSubscriptionUnmarshalBinaryEmpty(t *testing.T) {
+	d := Subscription{}
+	err := d.UnmarshalBinary([]byte{})
+	require.NoError(t, err)
+	require.Equal(t, Subscription{}, d)
+}
+
+func TestSysInfoMarshalBinary(t *testing.T) {
+	data, err := sysInfoStruct.MarshalBinary()
+	require.NoError(t, err)
+	require.JSONEq(t, string(sysInfoJSON), string(data))
+}
+
+func TestSysInfoUnmarshalBinary(t *testing.T) {
+	d := sysInfoStruct
+	err := d.UnmarshalBinary(sysInfoJSON)
+	require.NoError(t, err)
+	require.Equal(t, sysInfoStruct, d)
+}
+
+func TestSysInfoUnmarshalBinaryEmpty(t *testing.T) {
+	d := SystemInfo{}
+	err := d.UnmarshalBinary([]byte{})
+	require.NoError(t, err)
+	require.Equal(t, SystemInfo{}, d)
+}
+
+func TestMessageToPacket(t *testing.T) {
+	d := messageStruct
+	pk := d.ToPacket()
+
+	require.Equal(t, packets.Packet{
+		Payload: []byte("payload"),
+		FixedHeader: packets.FixedHeader{
+			Remaining: d.FixedHeader.Remaining,
+			Type:      d.FixedHeader.Type,
+			Qos:       d.FixedHeader.Qos,
+			Dup:       d.FixedHeader.Dup,
+			Retain:    d.FixedHeader.Retain,
+		},
+		Origin:    d.Origin,
+		TopicName: d.TopicName,
+		Properties: packets.Properties{
+			PayloadFormat:          d.Properties.PayloadFormat,
+			PayloadFormatFlag:      d.Properties.PayloadFormatFlag,
+			MessageExpiryInterval:  d.Properties.MessageExpiryInterval,
+			ContentType:            d.Properties.ContentType,
+			ResponseTopic:          d.Properties.ResponseTopic,
+			CorrelationData:        d.Properties.CorrelationData,
+			SubscriptionIdentifier: d.Properties.SubscriptionIdentifier,
+			TopicAlias:             d.Properties.TopicAlias,
+			User:                   d.Properties.User,
+		},
+		PacketID: 100,
+		Created:  d.Created,
+	}, pk)
+
+}