Restruct (#34)

* modify

* remove

* modify

* modify

* remove no use

* add online/offline notification

* modify

* format log

* add reference

README.md

@@ -77,8 +77,6 @@ Common Options:
 
 * Supports will messages  
 
-* Queue subscribe
-
 * Websocket Support
 
 * TLS/SSL Support
@@ -95,13 +93,6 @@ Common Options:
  
 ```
 
-### QUEUE SUBSCRIBE
-~~~
-| Prefix        | Examples                        |
-| ------------- |---------------------------------|
-| $queue/       | mosquitto_sub -t ‘$queue/topic’ |
-~~~
-
 ### ACL Configure
 #### The ACL rules define:
 ~~~
@@ -154,6 +145,14 @@ Client -> | Rule1 | --nomatch--> | Rule2 | --nomatch--> | Rule3 | -->
         allow | deny           allow | deny           allow | deny
 ~~~
 
+### Online/Offline Notification
+```bash
+ topic:
+     $SYS/broker/connection/clients/<clientID>
+ payload:
+	{"clientID":"client001","online":true/false,"timestamp":"2018-10-25T09:32:32Z"}
+```
+
 ## Performance
 
 * High throughput
@@ -166,3 +165,8 @@ Client -> | Rule1 | --nomatch--> | Rule2 | --nomatch--> | Rule3 | -->
 ## License
 
 * Apache License Version 2.0
+
+
+## Reference
+
+* Surgermq.(https://github.com/surgemq/surgemq)

broker/broker.go

@@ -4,6 +4,7 @@ package broker
 
 import (
 	"crypto/tls"
+	"fmt"
 	"net"
 	"net/http"
 	"runtime/debug"
@@ -13,6 +14,8 @@ import (
 
 	"github.com/eclipse/paho.mqtt.golang/packets"
 	"github.com/fhmq/hmq/lib/acl"
+	"github.com/fhmq/hmq/lib/sessions"
+	"github.com/fhmq/hmq/lib/topics"
 	"github.com/fhmq/hmq/pool"
 	"github.com/shirou/gopsutil/mem"
 	"go.uber.org/zap"
@@ -42,9 +45,9 @@ type Broker struct {
 	remotes     sync.Map
 	nodes       map[string]interface{}
 	clusterPool chan *Message
-	sl          *Sublist
-	rl          *RetainList
 	queues      map[string]int
+	topicsMgr   *topics.Manager
+	sessionMgr  *sessions.Manager
 	// messagePool []chan *Message
 }
 
@@ -62,13 +65,24 @@ func NewBroker(config *Config) (*Broker, error) {
 		id:          GenUniqueId(),
 		config:      config,
 		wpool:       pool.New(config.Worker),
-		sl:          NewSublist(),
-		rl:          NewRetainList(),
 		nodes:       make(map[string]interface{}),
 		queues:      make(map[string]int),
 		clusterPool: make(chan *Message),
-		// messagePool: newMessagePool(),
 	}
+
+	var err error
+	b.topicsMgr, err = topics.NewManager("mem")
+	if err != nil {
+		log.Error("new topic manager error", zap.Error(err))
+		return nil, err
+	}
+
+	b.sessionMgr, err = sessions.NewManager("mem")
+	if err != nil {
+		log.Error("new session manager error", zap.Error(err))
+		return nil, err
+	}
+
 	if b.config.TlsPort != "" {
 		tlsconfig, err := NewTLSConfig(b.config.TlsInfo)
 		if err != nil {
@@ -333,6 +347,12 @@ func (b *Broker) handleConnection(typ int, conn net.Conn) {
 
 	c.init()
 
+	err = b.getSession(c, msg, connack)
+	if err != nil {
+		log.Error("get session error: ", zap.String("clientID", c.info.clientID))
+		return
+	}
+
 	cid := c.info.clientID
 
 	var exist bool
@@ -349,6 +369,8 @@ func (b *Broker) handleConnection(typ int, conn net.Conn) {
 			}
 		}
 		b.clients.Store(cid, c)
+
+		b.OnlineOfflineNotification(cid, true)
 	case ROUTER:
 		old, exist = b.routes.Load(cid)
 		if exist {
@@ -535,9 +557,9 @@ func (b *Broker) SendLocalSubsToRouter(c *client) {
 	b.clients.Range(func(key, value interface{}) bool {
 		client, ok := value.(*client)
 		if ok {
-			subs := client.subs
+			subs := client.subMap
 			for _, sub := range subs {
-				subInfo.Topics = append(subInfo.Topics, string(sub.topic))
+				subInfo.Topics = append(subInfo.Topics, sub.topic)
 				subInfo.Qoss = append(subInfo.Qoss, sub.qos)
 			}
 		}
@@ -593,17 +615,20 @@ func (b *Broker) removeClient(c *client) {
 }
 
 func (b *Broker) PublishMessage(packet *packets.PublishPacket) {
-	topic := packet.TopicName
-	r := b.sl.Match(topic)
-	if len(r.psubs) == 0 {
+	var subs []interface{}
+	var qoss []byte
+	err := b.topicsMgr.Subscribers([]byte(packet.TopicName), packet.Qos, &subs, &qoss)
+	if err != nil {
+		log.Error("search sub client error,  ", zap.Error(err))
 		return
 	}
 
-	for _, sub := range r.psubs {
-		if sub != nil {
-			err := sub.client.WriterPacket(packet)
+	for _, sub := range subs {
+		s, ok := sub.(*subscription)
+		if ok {
+			err := s.client.WriterPacket(packet)
 			if err != nil {
-				log.Error("process message for psub error,  ", zap.Error(err))
+				log.Error("write message error,  ", zap.Error(err))
 			}
 		}
 	}
@@ -620,3 +645,12 @@ func (b *Broker) BroadcastUnSubscribe(subs map[string]*subscription) {
 		b.BroadcastSubOrUnsubMessage(unsub)
 	}
 }
+
+func (b *Broker) OnlineOfflineNotification(clientID string, online bool) {
+	packet := packets.NewControlPacket(packets.Publish).(*packets.PublishPacket)
+	packet.TopicName = "$SYS/broker/connection/clients/" + clientID
+	packet.Qos = 0
+	packet.Payload = []byte(fmt.Sprintf(`{"clientID":"%s","online":%v,"timestamp":"%s"}`, clientID, online, time.Now().UTC().Format(time.RFC3339)))
+
+	b.PublishMessage(packet)
+}

broker/client.go

@@ -12,6 +12,8 @@ import (
 	"time"
 
 	"github.com/eclipse/paho.mqtt.golang/packets"
+	"github.com/fhmq/hmq/lib/sessions"
+	"github.com/fhmq/hmq/lib/topics"
 	"go.uber.org/zap"
 )
 
@@ -39,11 +41,14 @@ type client struct {
 	info       info
 	route      route
 	status     int
-	smu        sync.RWMutex
-	subs       map[string]*subscription
-	rsubs      map[string]*subInfo
 	ctx        context.Context
 	cancelFunc context.CancelFunc
+	session    *sessions.Session
+	subMap     map[string]*subscription
+	topicsMgr  *topics.Manager
+	subs       []interface{}
+	qoss       []byte
+	rmsgs      []*packets.PublishPacket
 }
 
 type subInfo struct {
@@ -78,44 +83,12 @@ var (
 )
 
 func (c *client) init() {
-	c.smu.Lock()
-	defer c.smu.Unlock()
 	c.status = Connected
-	c.rsubs = make(map[string]*subInfo)
-	c.subs = make(map[string]*subscription, 10)
 	c.info.localIP = strings.Split(c.conn.LocalAddr().String(), ":")[0]
 	c.info.remoteIP = strings.Split(c.conn.RemoteAddr().String(), ":")[0]
 	c.ctx, c.cancelFunc = context.WithCancel(context.Background())
-}
-
-func (c *client) keepAlive(ch chan int) {
-	defer close(ch)
-
-	b := c.broker
-
-	keepalive := time.Duration(c.info.keepalive*3/2) * time.Second
-	timer := time.NewTimer(keepalive)
-
-	for {
-		select {
-		case <-ch:
-			timer.Reset(keepalive)
-		case <-timer.C:
-			if c.typ == REMOTE || c.typ == CLUSTER {
-				timer.Reset(keepalive)
-				continue
-			}
-			log.Error("Client exceeded timeout, disconnecting. ", zap.String("ClientID", c.info.clientID), zap.Uint16("keepalive", c.info.keepalive))
-
-			msg := &Message{client: c, packet: DisconnectdPacket}
-			b.SubmitWork(msg)
-
-			timer.Stop()
-			return
-		case <-c.ctx.Done():
-			return
-		}
-	}
+	c.subMap = make(map[string]*subscription)
+	c.topicsMgr = c.broker.topicsMgr
 }
 
 func (c *client) readLoop() {
@@ -125,14 +98,20 @@ func (c *client) readLoop() {
 		return
 	}
 
-	ch := make(chan int, 1000)
-	go c.keepAlive(ch)
+	keepAlive := time.Second * time.Duration(c.info.keepalive)
+	timeOut := keepAlive + (keepAlive / 2)
 
 	for {
 		select {
 		case <-c.ctx.Done():
 			return
 		default:
+			//add read timeout
+			if err := nc.SetReadDeadline(time.Now().Add(timeOut)); err != nil {
+				log.Error("set read timeout error: ", zap.Error(err), zap.String("ClientID", c.info.clientID))
+				return
+			}
+
 			packet, err := packets.ReadPacket(nc)
 			if err != nil {
 				log.Error("read packet error: ", zap.Error(err), zap.String("ClientID", c.info.clientID))
@@ -140,8 +119,6 @@ func (c *client) readLoop() {
 				b.SubmitWork(msg)
 				return
 			}
-			// keepalive channel
-			ch <- 1
 
 			msg := &Message{
 				client: c,
@@ -159,7 +136,6 @@ func ProcessMessage(msg *Message) {
 	if ca == nil {
 		return
 	}
-
 	log.Debug("Recv message:", zap.String("message type", reflect.TypeOf(msg.packet).String()[9:]), zap.String("ClientID", c.info.clientID))
 	switch ca.(type) {
 	case *packets.ConnackPacket:
@@ -222,14 +198,6 @@ func (c *client) ProcessPublish(packet *packets.PublishPacket) {
 		log.Error("publish with unknown qos", zap.String("ClientID", c.info.clientID))
 		return
 	}
-	if packet.Retain {
-		if b := c.broker; b != nil {
-			err := b.rl.Insert(topic, packet)
-			if err != nil {
-				log.Error("Insert Retain Message error: ", zap.Error(err), zap.String("ClientID", c.info.clientID))
-			}
-		}
-	}
 
 }
 
@@ -243,85 +211,40 @@ func (c *client) ProcessPublishMessage(packet *packets.PublishPacket) {
 		return
 	}
 	typ := c.typ
-	topic := packet.TopicName
 
-	r := b.sl.Match(topic)
-	if r == nil {
+	if packet.Retain {
+		if err := c.topicsMgr.Retain(packet); err != nil {
+			log.Error("Error retaining message: ", zap.Error(err), zap.String("ClientID", c.info.clientID))
+		}
+	}
+
+	err := c.topicsMgr.Subscribers([]byte(packet.TopicName), packet.Qos, &c.subs, &c.qoss)
+	if err != nil {
+		log.Error("Error retrieving subscribers list: ", zap.String("ClientID", c.info.clientID))
 		return
 	}
 
 	// log.Info("psubs num: ", len(r.psubs))
-	if len(r.qsubs) == 0 && len(r.psubs) == 0 {
+	if len(c.subs) == 0 {
 		return
 	}
 
-	for _, sub := range r.psubs {
-		if sub.client.typ == ROUTER {
-			if typ != CLIENT {
-				continue
-			}
-		}
-		if sub != nil {
-			err := sub.client.WriterPacket(packet)
-			if err != nil {
-				log.Error("process message for psub error,  ", zap.Error(err), zap.String("ClientID", c.info.clientID))
-			}
-		}
-	}
-
-	pre := -1
-	now := -1
-	t := "$queue/" + topic
-	cnt, exist := b.queues[t]
-	if exist {
-		// log.Info("queue index : ", cnt)
-		for _, sub := range r.qsubs {
-			if sub.client.typ == ROUTER {
+	for _, sub := range c.subs {
+		s, ok := sub.(*subscription)
+		if ok {
+			if s.client.typ == ROUTER {
 				if typ != CLIENT {
 					continue
 				}
 			}
-			if c.typ == CLIENT {
-				now = now + 1
-			} else {
-				now = now + sub.client.rsubs[t].num
+			err := s.client.WriterPacket(packet)
+			if err != nil {
+				log.Error("process message for psub error,  ", zap.Error(err), zap.String("ClientID", c.info.clientID))
 			}
-			if cnt > pre && cnt <= now {
-				if sub != nil {
-					err := sub.client.WriterPacket(packet)
-					if err != nil {
-						log.Error("send publish error, ", zap.Error(err), zap.String("ClientID", c.info.clientID))
-					}
-				}
-
-				break
-			}
-			pre = now
 		}
+
 	}
 
-	length := getQueueSubscribeNum(r.qsubs)
-	if length > 0 {
-		b.queues[t] = (b.queues[t] + 1) % length
-	}
-}
-
-func getQueueSubscribeNum(qsubs []*subscription) int {
-	topic := "$queue/"
-	if len(qsubs) < 1 {
-		return 0
-	} else {
-		topic = topic + qsubs[0].topic
-	}
-	num := 0
-	for _, sub := range qsubs {
-		if sub.client.typ == CLIENT {
-			num = num + 1
-		} else {
-			num = num + sub.client.rsubs[topic].num
-		}
-	}
-	return num
 }
 
 func (c *client) ProcessSubscribe(packet *packets.SubscribePacket) {
@@ -349,54 +272,24 @@ func (c *client) ProcessSubscribe(packet *packets.SubscribePacket) {
 			continue
 		}
 
-		queue := strings.HasPrefix(topic, "$queue/")
-		if queue {
-			if len(t) > 7 {
-				t = t[7:]
-				if _, exists := b.queues[topic]; !exists {
-					b.queues[topic] = 0
-				}
-			} else {
-				retcodes = append(retcodes, QosFailure)
-				continue
-			}
-		}
 		sub := &subscription{
 			topic:  t,
 			qos:    qoss[i],
 			client: c,
-			queue:  queue,
 		}
-		switch c.typ {
-		case CLIENT:
-			if _, exist := c.subs[topic]; !exist {
-				c.subs[topic] = sub
 
-			} else {
-				//if exist ,check whether qos change
-				c.subs[topic].qos = qoss[i]
-				retcodes = append(retcodes, qoss[i])
-				continue
-			}
-		case ROUTER:
-			if subinfo, exist := c.rsubs[topic]; !exist {
-				sinfo := &subInfo{sub: sub, num: 1}
-				c.rsubs[topic] = sinfo
-
-			} else {
-				subinfo.num = subinfo.num + 1
-				retcodes = append(retcodes, qoss[i])
-				continue
-			}
-		}
-		err := b.sl.Insert(sub)
+		rqos, err := c.topicsMgr.Subscribe([]byte(topic), qoss[i], sub)
 		if err != nil {
-			log.Error("Insert subscription error: ", zap.Error(err), zap.String("ClientID", c.info.clientID))
-			retcodes = append(retcodes, QosFailure)
-		} else {
-			retcodes = append(retcodes, qoss[i])
+			return
 		}
+
+		c.subMap[topic] = sub
+		c.session.AddTopic(topic, qoss[i])
+		retcodes = append(retcodes, rqos)
+		c.topicsMgr.Retained([]byte(topic), &c.rmsgs)
+
 	}
+
 	suback.ReturnCodes = retcodes
 
 	err := c.WriterPacket(suback)
@@ -410,16 +303,11 @@ func (c *client) ProcessSubscribe(packet *packets.SubscribePacket) {
 	}
 
 	//process retain message
-	for _, t := range topics {
-		packets := b.rl.Match(t)
-		if packets == nil {
-			continue
-		}
-		for _, packet := range packets {
+	for _, rm := range c.rmsgs {
+		if err := c.WriterPacket(rm); err != nil {
+			log.Error("Error publishing retained message:", zap.Any("err", err), zap.String("ClientID", c.info.clientID))
+		} else {
 			log.Info("process retain  message: ", zap.Any("packet", packet), zap.String("ClientID", c.info.clientID))
-			if packet != nil {
-				c.WriterPacket(packet)
-			}
 		}
 	}
 }
@@ -432,30 +320,16 @@ func (c *client) ProcessUnSubscribe(packet *packets.UnsubscribePacket) {
 	if b == nil {
 		return
 	}
-	typ := c.typ
 	topics := packet.Topics
 
-	for _, t := range topics {
-
-		switch typ {
-		case CLIENT:
-			sub, ok := c.subs[t]
-			if ok {
-				c.unsubscribe(sub)
-			}
-		case ROUTER:
-			subinfo, ok := c.rsubs[t]
-			if ok {
-				subinfo.num = subinfo.num - 1
-				if subinfo.num < 1 {
-					delete(c.rsubs, t)
-					c.unsubscribe(subinfo.sub)
-				} else {
-					c.rsubs[t] = subinfo
-				}
-			}
+	for _, topic := range topics {
+		t := []byte(topic)
+		sub, exist := c.subMap[topic]
+		if exist {
+			c.topicsMgr.Unsubscribe(t, sub)
+			c.session.RemoveTopic(topic)
+			delete(c.subMap, topic)
 		}
-
 	}
 
 	unsuback := packets.NewControlPacket(packets.Unsuback).(*packets.UnsubackPacket)
@@ -472,19 +346,6 @@ func (c *client) ProcessUnSubscribe(packet *packets.UnsubscribePacket) {
 	}
 }
 
-func (c *client) unsubscribe(sub *subscription) {
-
-	if c.typ == CLIENT {
-		delete(c.subs, sub.topic)
-
-	}
-	b := c.broker
-	if b != nil && sub != nil {
-		b.sl.Remove(sub)
-	}
-
-}
-
 func (c *client) ProcessPing() {
 	if c.status == Disconnected {
 		return
@@ -498,9 +359,7 @@ func (c *client) ProcessPing() {
 }
 
 func (c *client) Close() {
-	c.smu.Lock()
 	if c.status == Disconnected {
-		c.smu.Unlock()
 		return
 	}
 
@@ -516,21 +375,17 @@ func (c *client) Close() {
 		c.conn = nil
 	}
 
-	c.smu.Unlock()
-
 	b := c.broker
-	subs := c.subs
+	subs := c.subMap
 	if b != nil {
 		b.removeClient(c)
-		for _, sub := range subs {
-			err := b.sl.Remove(sub)
-			if err != nil {
-				log.Error("closed client but remove sublist error, ", zap.Error(err), zap.String("ClientID", c.info.clientID))
-			}
-		}
+
 		if c.typ == CLIENT {
 			b.BroadcastUnSubscribe(subs)
+			//offline notification
+			b.OnlineOfflineNotification(c.info.clientID, false)
 		}
+
 		if c.info.willMsg != nil {
 			b.PublishMessage(c.info.willMsg)
 		}

broker/comm.go

@@ -7,10 +7,8 @@ import (
 	"crypto/rand"
 	"encoding/base64"
 	"encoding/hex"
-	"errors"
 	"io"
 	"reflect"
-	"strings"
 	"time"
 )
 
@@ -48,47 +46,6 @@ const (
 	QosFailure = 0x80
 )
 
-func SubscribeTopicCheckAndSpilt(topic string) ([]string, error) {
-	if strings.Index(topic, "#") != -1 && strings.Index(topic, "#") != len(topic)-1 {
-		return nil, errors.New("Topic format error with index of #")
-	}
-	re := strings.Split(topic, "/")
-	for i, v := range re {
-		if i != 0 && i != (len(re)-1) {
-			if v == "" {
-				return nil, errors.New("Topic format error with index of //")
-			}
-			if strings.Contains(v, "+") && v != "+" {
-				return nil, errors.New("Topic format error with index of +")
-			}
-		} else {
-			if v == "" {
-				re[i] = "/"
-			}
-		}
-	}
-	return re, nil
-
-}
-
-func PublishTopicCheckAndSpilt(topic string) ([]string, error) {
-	if strings.Index(topic, "#") != -1 || strings.Index(topic, "+") != -1 {
-		return nil, errors.New("Publish Topic format error with + and #")
-	}
-	re := strings.Split(topic, "/")
-	for i, v := range re {
-		if v == "" {
-			if i != 0 && i != (len(re)-1) {
-				return nil, errors.New("Topic format error with index of //")
-			} else {
-				re[i] = "/"
-			}
-		}
-
-	}
-	return re, nil
-}
-
 func equal(k1, k2 interface{}) bool {
 	if reflect.TypeOf(k1) != reflect.TypeOf(k2) {
 		return false

broker/config.go

@@ -9,10 +9,11 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"github.com/fhmq/hmq/logger"
-	"go.uber.org/zap"
 	"io/ioutil"
 	"os"
+
+	"github.com/fhmq/hmq/logger"
+	"go.uber.org/zap"
 )
 
 type Config struct {

broker/retain.go

@@ -1,121 +0,0 @@
-package broker
-
-import (
-	"github.com/eclipse/paho.mqtt.golang/packets"
-	"sync"
-)
-
-type RetainList struct {
-	sync.RWMutex
-	root *rlevel
-}
-type rlevel struct {
-	nodes map[string]*rnode
-}
-type rnode struct {
-	next *rlevel
-	msg  *packets.PublishPacket
-}
-type RetainResult struct {
-	msg []*packets.PublishPacket
-}
-
-func newRNode() *rnode {
-	return &rnode{}
-}
-
-func newRLevel() *rlevel {
-	return &rlevel{nodes: make(map[string]*rnode)}
-}
-
-func NewRetainList() *RetainList {
-	return &RetainList{root: newRLevel()}
-}
-
-func (r *RetainList) Insert(topic string, buf *packets.PublishPacket) error {
-
-	tokens, err := PublishTopicCheckAndSpilt(topic)
-	if err != nil {
-		return err
-	}
-	// log.Info("insert tokens:", tokens)
-	r.Lock()
-
-	l := r.root
-	var n *rnode
-	for _, t := range tokens {
-		n = l.nodes[t]
-		if n == nil {
-			n = newRNode()
-			l.nodes[t] = n
-		}
-		if n.next == nil {
-			n.next = newRLevel()
-		}
-		l = n.next
-	}
-	n.msg = buf
-	r.Unlock()
-	return nil
-}
-
-func (r *RetainList) Match(topic string) []*packets.PublishPacket {
-
-	tokens, err := SubscribeTopicCheckAndSpilt(topic)
-	if err != nil {
-		return nil
-	}
-	results := &RetainResult{}
-
-	r.Lock()
-	l := r.root
-	matchRLevel(l, tokens, results)
-	r.Unlock()
-	// log.Info("results: ", results)
-	return results.msg
-
-}
-func matchRLevel(l *rlevel, toks []string, results *RetainResult) {
-	var n *rnode
-	for i, t := range toks {
-		if l == nil {
-			return
-		}
-		// log.Info("l info :", l.nodes)
-		if t == "#" {
-			for _, n := range l.nodes {
-				n.GetAll(results)
-			}
-		}
-		if t == "+" {
-			for _, n := range l.nodes {
-				if len(t[i+1:]) == 0 {
-					results.msg = append(results.msg, n.msg)
-				} else {
-					matchRLevel(n.next, toks[i+1:], results)
-				}
-			}
-		}
-
-		n = l.nodes[t]
-		if n != nil {
-			l = n.next
-		} else {
-			l = nil
-		}
-	}
-	if n != nil {
-		results.msg = append(results.msg, n.msg)
-	}
-}
-
-func (r *rnode) GetAll(results *RetainResult) {
-	// log.Info("node 's message: ", string(r.msg))
-	if r.msg != nil {
-		results.msg = append(results.msg, r.msg)
-	}
-	l := r.next
-	for _, n := range l.nodes {
-		n.GetAll(results)
-	}
-}

broker/sesson.go

@@ -0,0 +1,53 @@
+package broker
+
+import "github.com/eclipse/paho.mqtt.golang/packets"
+
+func (b *Broker) getSession(cli *client, req *packets.ConnectPacket, resp *packets.ConnackPacket) error {
+	// If CleanSession is set to 0, the server MUST resume communications with the
+	// client based on state from the current session, as identified by the client
+	// identifier. If there is no session associated with the client identifier the
+	// server must create a new session.
+	//
+	// If CleanSession is set to 1, the client and server must discard any previous
+	// session and start a new one. b session lasts as long as the network c
+	// onnection. State data associated with b session must not be reused in any
+	// subsequent session.
+
+	var err error
+
+	// Check to see if the client supplied an ID, if not, generate one and set
+	// clean session.
+
+	if len(req.ClientIdentifier) == 0 {
+		req.CleanSession = true
+	}
+
+	cid := req.ClientIdentifier
+
+	// If CleanSession is NOT set, check the session store for existing session.
+	// If found, return it.
+	if !req.CleanSession {
+		if cli.session, err = b.sessionMgr.Get(cid); err == nil {
+			resp.SessionPresent = true
+
+			if err := cli.session.Update(req); err != nil {
+				return err
+			}
+		}
+	}
+
+	// If CleanSession, or no existing session found, then create a new one
+	if cli.session == nil {
+		if cli.session, err = b.sessionMgr.New(cid); err != nil {
+			return err
+		}
+
+		resp.SessionPresent = false
+
+		if err := cli.session.Init(req); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

broker/sublist.go

@@ -1,317 +0,0 @@
-/* Copyright (c) 2018, joy.zhou <chowyu08@gmail.com>
- */
-package broker
-
-import (
-	"errors"
-	"go.uber.org/zap"
-	"sync"
-)
-
-// A result structure better optimized for queue subs.
-type SublistResult struct {
-	psubs []*subscription
-	qsubs []*subscription // don't make this a map, too expensive to iterate
-}
-
-// A Sublist stores and efficiently retrieves subscriptions.
-type Sublist struct {
-	sync.RWMutex
-	cache map[string]*SublistResult
-	root  *level
-}
-
-// A node contains subscriptions and a pointer to the next level.
-type node struct {
-	next  *level
-	psubs []*subscription
-	qsubs []*subscription
-}
-
-// A level represents a group of nodes and special pointers to
-// wildcard nodes.
-type level struct {
-	nodes map[string]*node
-}
-
-// Create a new default node.
-func newNode() *node {
-	return &node{psubs: make([]*subscription, 0, 4), qsubs: make([]*subscription, 0, 4)}
-}
-
-// Create a new default level. We use FNV1A as the hash
-// algortihm for the tokens, which should be short.
-func newLevel() *level {
-	return &level{nodes: make(map[string]*node)}
-}
-
-// New will create a default sublist
-func NewSublist() *Sublist {
-	return &Sublist{root: newLevel(), cache: make(map[string]*SublistResult)}
-}
-
-// Insert adds a subscription into the sublist
-func (s *Sublist) Insert(sub *subscription) error {
-
-	tokens, err := SubscribeTopicCheckAndSpilt(sub.topic)
-	if err != nil {
-		return err
-	}
-	s.Lock()
-
-	l := s.root
-	var n *node
-	for _, t := range tokens {
-		n = l.nodes[t]
-		if n == nil {
-			n = newNode()
-			l.nodes[t] = n
-		}
-		if n.next == nil {
-			n.next = newLevel()
-		}
-		l = n.next
-	}
-	if sub.queue {
-		//check qsub is already exist
-		for i := range n.qsubs {
-			if equal(n.qsubs[i], sub) {
-				n.qsubs[i] = sub
-				return nil
-			}
-		}
-		n.qsubs = append(n.qsubs, sub)
-	} else {
-		//check psub is already exist
-		for i := range n.psubs {
-			if equal(n.psubs[i], sub) {
-				n.psubs[i] = sub
-				return nil
-			}
-		}
-		n.psubs = append(n.psubs, sub)
-	}
-
-	topic := string(sub.topic)
-	s.addToCache(topic, sub)
-	s.Unlock()
-	return nil
-}
-
-func (s *Sublist) addToCache(topic string, sub *subscription) {
-	for k, r := range s.cache {
-		if matchLiteral(k, topic) {
-			// Copy since others may have a reference.
-			nr := copyResult(r)
-			if sub.queue == false {
-				nr.psubs = append(nr.psubs, sub)
-			} else {
-				nr.qsubs = append(nr.qsubs, sub)
-			}
-			s.cache[k] = nr
-		}
-	}
-}
-
-func (s *Sublist) removeFromCache(topic string, sub *subscription) {
-	for k := range s.cache {
-		if !matchLiteral(k, topic) {
-			continue
-		}
-		// Since someone else may be referecing, can't modify the list
-		// safely, just let it re-populate.
-		delete(s.cache, k)
-	}
-}
-
-func matchLiteral(literal, topic string) bool {
-	tok, _ := SubscribeTopicCheckAndSpilt(topic)
-	li, _ := PublishTopicCheckAndSpilt(literal)
-
-	for i := 0; i < len(tok); i++ {
-		b := tok[i]
-		switch b {
-		case "+":
-
-		case "#":
-			return true
-		default:
-			if b != li[i] {
-				return false
-			}
-		}
-	}
-	return true
-}
-
-// Deep copy
-func copyResult(r *SublistResult) *SublistResult {
-	nr := &SublistResult{}
-	nr.psubs = append([]*subscription(nil), r.psubs...)
-	nr.qsubs = append([]*subscription(nil), r.qsubs...)
-	return nr
-}
-
-func (s *Sublist) Remove(sub *subscription) error {
-	tokens, err := SubscribeTopicCheckAndSpilt(sub.topic)
-	if err != nil {
-		return err
-	}
-	s.Lock()
-	defer s.Unlock()
-
-	l := s.root
-	var n *node
-
-	for _, t := range tokens {
-		if l == nil {
-			return errors.New("No Matches subscription Found")
-		}
-		n = l.nodes[t]
-		if n != nil {
-			l = n.next
-		} else {
-			l = nil
-		}
-	}
-	if !s.removeFromNode(n, sub) {
-		return errors.New("No Matches subscription Found")
-	}
-	topic := string(sub.topic)
-	s.removeFromCache(topic, sub)
-	return nil
-
-}
-
-func (s *Sublist) removeFromNode(n *node, sub *subscription) (found bool) {
-	if n == nil {
-		return false
-	}
-
-	if sub.queue {
-		n.qsubs, found = removeSubFromList(sub, n.qsubs)
-		return found
-	} else {
-		n.psubs, found = removeSubFromList(sub, n.psubs)
-		return found
-	}
-
-	return false
-}
-
-func (s *Sublist) Match(topic string) *SublistResult {
-	s.RLock()
-	rc, ok := s.cache[topic]
-	s.RUnlock()
-
-	if ok {
-		return rc
-	}
-
-	tokens, err := PublishTopicCheckAndSpilt(topic)
-	if err != nil {
-		log.Error("\tserver/sublist.go: ", zap.Error(err))
-		return nil
-	}
-
-	result := &SublistResult{}
-
-	s.Lock()
-	l := s.root
-	if len(tokens) > 0 {
-		if tokens[0] == "/" {
-			if _, exist := l.nodes["#"]; exist {
-				addNodeToResults(l.nodes["#"], result)
-			}
-			if _, exist := l.nodes["+"]; exist {
-				matchLevel(l.nodes["/"].next, tokens[1:], result)
-			}
-			if _, exist := l.nodes["/"]; exist {
-				matchLevel(l.nodes["/"].next, tokens[1:], result)
-			}
-		} else {
-			matchLevel(s.root, tokens, result)
-		}
-	}
-	s.cache[topic] = result
-	if len(s.cache) > 1024 {
-		for k := range s.cache {
-			delete(s.cache, k)
-			break
-		}
-	}
-
-	s.Unlock()
-	return result
-}
-
-func matchLevel(l *level, toks []string, results *SublistResult) {
-	var swc, n *node
-	exist := false
-	for i, t := range toks {
-		if l == nil {
-			return
-		}
-
-		if _, exist = l.nodes["#"]; exist {
-			addNodeToResults(l.nodes["#"], results)
-		}
-		if t != "/" {
-			if swc, exist = l.nodes["+"]; exist {
-				matchLevel(l.nodes["+"].next, toks[i+1:], results)
-			}
-		} else {
-			if _, exist = l.nodes["+"]; exist {
-				addNodeToResults(l.nodes["+"], results)
-			}
-		}
-
-		n = l.nodes[t]
-		if n != nil {
-			l = n.next
-		} else {
-			l = nil
-		}
-	}
-	if n != nil {
-		addNodeToResults(n, results)
-	}
-	if swc != nil {
-		addNodeToResults(n, results)
-	}
-}
-
-// This will add in a node's results to the total results.
-func addNodeToResults(n *node, results *SublistResult) {
-	results.psubs = append(results.psubs, n.psubs...)
-	results.qsubs = append(results.qsubs, n.qsubs...)
-}
-
-func removeSubFromList(sub *subscription, sl []*subscription) ([]*subscription, bool) {
-	for i := 0; i < len(sl); i++ {
-		if sl[i] == sub {
-			last := len(sl) - 1
-			sl[i] = sl[last]
-			sl[last] = nil
-			sl = sl[:last]
-			return shrinkAsNeeded(sl), true
-		}
-	}
-	return sl, false
-}
-
-// Checks if we need to do a resize. This is for very large growth then
-// subsequent return to a more normal size from unsubscribe.
-func shrinkAsNeeded(sl []*subscription) []*subscription {
-	lsl := len(sl)
-	csl := cap(sl)
-	// Don't bother if list not too big
-	if csl <= 8 {
-		return sl
-	}
-	pFree := float32(csl-lsl) / float32(csl)
-	if pFree > 0.50 {
-		return append([]*subscription(nil), sl...)
-	}
-	return sl
-}

lib/sessions/memprovider.go

@@ -0,0 +1,76 @@
+// Copyright (c) 2014 The SurgeMQ Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sessions
+
+import (
+	"fmt"
+	"sync"
+)
+
+var _ SessionsProvider = (*memProvider)(nil)
+
+func init() {
+	Register("mem", NewMemProvider())
+}
+
+type memProvider struct {
+	st map[string]*Session
+	mu sync.RWMutex
+}
+
+func NewMemProvider() *memProvider {
+	return &memProvider{
+		st: make(map[string]*Session),
+	}
+}
+
+func (this *memProvider) New(id string) (*Session, error) {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+
+	this.st[id] = &Session{id: id}
+	return this.st[id], nil
+}
+
+func (this *memProvider) Get(id string) (*Session, error) {
+	this.mu.RLock()
+	defer this.mu.RUnlock()
+
+	sess, ok := this.st[id]
+	if !ok {
+		return nil, fmt.Errorf("store/Get: No session found for key %s", id)
+	}
+
+	return sess, nil
+}
+
+func (this *memProvider) Del(id string) {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	delete(this.st, id)
+}
+
+func (this *memProvider) Save(id string) error {
+	return nil
+}
+
+func (this *memProvider) Count() int {
+	return len(this.st)
+}
+
+func (this *memProvider) Close() error {
+	this.st = make(map[string]*Session)
+	return nil
+}

lib/sessions/redisprovider.go

@@ -0,0 +1,95 @@
+package sessions
+
+import (
+	"time"
+
+	log "github.com/cihub/seelog"
+	"github.com/go-redis/redis"
+	jsoniter "github.com/json-iterator/go"
+)
+
+var redisClient *redis.Client
+var _ SessionsProvider = (*redisProvider)(nil)
+
+const (
+	sessionName = "session"
+)
+
+type redisProvider struct {
+}
+
+func init() {
+	Register("redis", NewRedisProvider())
+}
+
+func InitRedisConn(url string) {
+	redisClient = redis.NewClient(&redis.Options{
+		Addr:     "127.0.0.1:6379",
+		Password: "", // no password set
+		DB:       0,  // use default DB
+	})
+	err := redisClient.Ping().Err()
+	for err != nil {
+		log.Error("connect redis error: ", err, " 3s try again...")
+		time.Sleep(3 * time.Second)
+		err = redisClient.Ping().Err()
+	}
+}
+
+func NewRedisProvider() *redisProvider {
+	return &redisProvider{}
+}
+
+func (r *redisProvider) New(id string) (*Session, error) {
+	val, _ := jsoniter.Marshal(&Session{id: id})
+
+	err := redisClient.HSet(sessionName, id, val).Err()
+	if err != nil {
+		return nil, err
+	}
+
+	result, err := redisClient.HGet(sessionName, id).Bytes()
+	if err != nil {
+		return nil, err
+	}
+
+	sess := Session{}
+	err = jsoniter.Unmarshal(result, &sess)
+	if err != nil {
+		return nil, err
+	}
+
+	return &sess, nil
+}
+
+func (r *redisProvider) Get(id string) (*Session, error) {
+
+	result, err := redisClient.HGet(sessionName, id).Bytes()
+	if err != nil {
+		return nil, err
+	}
+
+	sess := Session{}
+	err = jsoniter.Unmarshal(result, &sess)
+	if err != nil {
+		return nil, err
+	}
+
+	return &sess, nil
+}
+
+func (r *redisProvider) Del(id string) {
+	redisClient.HDel(sessionName, id)
+}
+
+func (r *redisProvider) Save(id string) error {
+	return nil
+}
+
+func (r *redisProvider) Count() int {
+	return int(redisClient.HLen(sessionName).Val())
+}
+
+func (r *redisProvider) Close() error {
+	return redisClient.Del(sessionName).Err()
+}

lib/sessions/session.go

@@ -0,0 +1,149 @@
+package sessions
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/eclipse/paho.mqtt.golang/packets"
+)
+
+const (
+	// Queue size for the ack queue
+	defaultQueueSize = 16
+)
+
+type Session struct {
+
+	// cmsg is the CONNECT message
+	cmsg *packets.ConnectPacket
+
+	// Will message to publish if connect is closed unexpectedly
+	Will *packets.PublishPacket
+
+	// Retained publish message
+	Retained *packets.PublishPacket
+
+	// topics stores all the topis for this session/client
+	topics map[string]byte
+
+	// Initialized?
+	initted bool
+
+	// Serialize access to this session
+	mu sync.Mutex
+
+	id string
+}
+
+func (this *Session) Init(msg *packets.ConnectPacket) error {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+
+	if this.initted {
+		return fmt.Errorf("Session already initialized")
+	}
+
+	this.cmsg = msg
+
+	if this.cmsg.WillFlag {
+		this.Will = packets.NewControlPacket(packets.Publish).(*packets.PublishPacket)
+		this.Will.Qos = this.cmsg.Qos
+		this.Will.TopicName = this.cmsg.WillTopic
+		this.Will.Payload = this.cmsg.WillMessage
+		this.Will.Retain = this.cmsg.WillRetain
+	}
+
+	this.topics = make(map[string]byte, 1)
+
+	this.id = string(msg.ClientIdentifier)
+
+	this.initted = true
+
+	return nil
+}
+
+func (this *Session) Update(msg *packets.ConnectPacket) error {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+
+	this.cmsg = msg
+	return nil
+}
+
+func (this *Session) RetainMessage(msg *packets.PublishPacket) error {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+
+	this.Retained = msg
+
+	return nil
+}
+
+func (this *Session) AddTopic(topic string, qos byte) error {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+
+	if !this.initted {
+		return fmt.Errorf("Session not yet initialized")
+	}
+
+	this.topics[topic] = qos
+
+	return nil
+}
+
+func (this *Session) RemoveTopic(topic string) error {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+
+	if !this.initted {
+		return fmt.Errorf("Session not yet initialized")
+	}
+
+	delete(this.topics, topic)
+
+	return nil
+}
+
+func (this *Session) Topics() ([]string, []byte, error) {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+
+	if !this.initted {
+		return nil, nil, fmt.Errorf("Session not yet initialized")
+	}
+
+	var (
+		topics []string
+		qoss   []byte
+	)
+
+	for k, v := range this.topics {
+		topics = append(topics, k)
+		qoss = append(qoss, v)
+	}
+
+	return topics, qoss, nil
+}
+
+func (this *Session) ID() string {
+	return this.cmsg.ClientIdentifier
+}
+
+func (this *Session) WillFlag() bool {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	return this.cmsg.WillFlag
+}
+
+func (this *Session) SetWillFlag(v bool) {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	this.cmsg.WillFlag = v
+}
+
+func (this *Session) CleanSession() bool {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	return this.cmsg.CleanSession
+}

lib/sessions/sessions.go

@@ -0,0 +1,92 @@
+package sessions
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+)
+
+var (
+	ErrSessionsProviderNotFound = errors.New("Session: Session provider not found")
+	ErrKeyNotAvailable          = errors.New("Session: not item found for key.")
+
+	providers = make(map[string]SessionsProvider)
+)
+
+type SessionsProvider interface {
+	New(id string) (*Session, error)
+	Get(id string) (*Session, error)
+	Del(id string)
+	Save(id string) error
+	Count() int
+	Close() error
+}
+
+// Register makes a session provider available by the provided name.
+// If a Register is called twice with the same name or if the driver is nil,
+// it panics.
+func Register(name string, provider SessionsProvider) {
+	if provider == nil {
+		panic("session: Register provide is nil")
+	}
+
+	if _, dup := providers[name]; dup {
+		panic("session: Register called twice for provider " + name)
+	}
+
+	providers[name] = provider
+}
+
+func Unregister(name string) {
+	delete(providers, name)
+}
+
+type Manager struct {
+	p SessionsProvider
+}
+
+func NewManager(providerName string) (*Manager, error) {
+	p, ok := providers[providerName]
+	if !ok {
+		return nil, fmt.Errorf("session: unknown provider %q", providerName)
+	}
+
+	return &Manager{p: p}, nil
+}
+
+func (this *Manager) New(id string) (*Session, error) {
+	if id == "" {
+		id = this.sessionId()
+	}
+	return this.p.New(id)
+}
+
+func (this *Manager) Get(id string) (*Session, error) {
+	return this.p.Get(id)
+}
+
+func (this *Manager) Del(id string) {
+	this.p.Del(id)
+}
+
+func (this *Manager) Save(id string) error {
+	return this.p.Save(id)
+}
+
+func (this *Manager) Count() int {
+	return this.p.Count()
+}
+
+func (this *Manager) Close() error {
+	return this.p.Close()
+}
+
+func (manager *Manager) sessionId() string {
+	b := make([]byte, 15)
+	if _, err := io.ReadFull(rand.Reader, b); err != nil {
+		return ""
+	}
+	return base64.URLEncoding.EncodeToString(b)
+}

lib/topics/memtopics.go

@@ -0,0 +1,549 @@
+package topics
+
+import (
+	"fmt"
+	"reflect"
+	"sync"
+
+	"github.com/eclipse/paho.mqtt.golang/packets"
+)
+
+const (
+	QosAtMostOnce byte = iota
+	QosAtLeastOnce
+	QosExactlyOnce
+	QosFailure = 0x80
+)
+
+var _ TopicsProvider = (*memTopics)(nil)
+
+type memTopics struct {
+	// Sub/unsub mutex
+	smu sync.RWMutex
+	// Subscription tree
+	sroot *snode
+
+	// Retained message mutex
+	rmu sync.RWMutex
+	// Retained messages topic tree
+	rroot *rnode
+}
+
+func init() {
+	Register("mem", NewMemProvider())
+}
+
+// NewMemProvider returns an new instance of the memTopics, which is implements the
+// TopicsProvider interface. memProvider is a hidden struct that stores the topic
+// subscriptions and retained messages in memory. The content is not persistend so
+// when the server goes, everything will be gone. Use with care.
+func NewMemProvider() *memTopics {
+	return &memTopics{
+		sroot: newSNode(),
+		rroot: newRNode(),
+	}
+}
+
+func ValidQos(qos byte) bool {
+	return qos == QosAtMostOnce || qos == QosAtLeastOnce || qos == QosExactlyOnce
+}
+
+func (this *memTopics) Subscribe(topic []byte, qos byte, sub interface{}) (byte, error) {
+	if !ValidQos(qos) {
+		return QosFailure, fmt.Errorf("Invalid QoS %d", qos)
+	}
+
+	if sub == nil {
+		return QosFailure, fmt.Errorf("Subscriber cannot be nil")
+	}
+
+	this.smu.Lock()
+	defer this.smu.Unlock()
+
+	if qos > QosExactlyOnce {
+		qos = QosExactlyOnce
+	}
+
+	if err := this.sroot.sinsert(topic, qos, sub); err != nil {
+		return QosFailure, err
+	}
+
+	return qos, nil
+}
+
+func (this *memTopics) Unsubscribe(topic []byte, sub interface{}) error {
+	this.smu.Lock()
+	defer this.smu.Unlock()
+
+	return this.sroot.sremove(topic, sub)
+}
+
+// Returned values will be invalidated by the next Subscribers call
+func (this *memTopics) Subscribers(topic []byte, qos byte, subs *[]interface{}, qoss *[]byte) error {
+	if !ValidQos(qos) {
+		return fmt.Errorf("Invalid QoS %d", qos)
+	}
+
+	this.smu.RLock()
+	defer this.smu.RUnlock()
+
+	*subs = (*subs)[0:0]
+	*qoss = (*qoss)[0:0]
+
+	return this.sroot.smatch(topic, qos, subs, qoss)
+}
+
+func (this *memTopics) Retain(msg *packets.PublishPacket) error {
+	this.rmu.Lock()
+	defer this.rmu.Unlock()
+
+	// So apparently, at least according to the MQTT Conformance/Interoperability
+	// Testing, that a payload of 0 means delete the retain message.
+	// https://eclipse.org/paho/clients/testing/
+	if len(msg.Payload) == 0 {
+		return this.rroot.rremove([]byte(msg.TopicName))
+	}
+
+	return this.rroot.rinsert([]byte(msg.TopicName), msg)
+}
+
+func (this *memTopics) Retained(topic []byte, msgs *[]*packets.PublishPacket) error {
+	this.rmu.RLock()
+	defer this.rmu.RUnlock()
+
+	return this.rroot.rmatch(topic, msgs)
+}
+
+func (this *memTopics) Close() error {
+	this.sroot = nil
+	this.rroot = nil
+	return nil
+}
+
+// subscrition nodes
+type snode struct {
+	// If this is the end of the topic string, then add subscribers here
+	subs []interface{}
+	qos  []byte
+
+	// Otherwise add the next topic level here
+	snodes map[string]*snode
+}
+
+func newSNode() *snode {
+	return &snode{
+		snodes: make(map[string]*snode),
+	}
+}
+
+func (this *snode) sinsert(topic []byte, qos byte, sub interface{}) error {
+	// If there's no more topic levels, that means we are at the matching snode
+	// to insert the subscriber. So let's see if there's such subscriber,
+	// if so, update it. Otherwise insert it.
+	if len(topic) == 0 {
+		// Let's see if the subscriber is already on the list. If yes, update
+		// QoS and then return.
+		for i := range this.subs {
+			if equal(this.subs[i], sub) {
+				this.qos[i] = qos
+				return nil
+			}
+		}
+
+		// Otherwise add.
+		this.subs = append(this.subs, sub)
+		this.qos = append(this.qos, qos)
+
+		return nil
+	}
+
+	// Not the last level, so let's find or create the next level snode, and
+	// recursively call it's insert().
+
+	// ntl = next topic level
+	ntl, rem, err := nextTopicLevel(topic)
+	if err != nil {
+		return err
+	}
+
+	level := string(ntl)
+
+	// Add snode if it doesn't already exist
+	n, ok := this.snodes[level]
+	if !ok {
+		n = newSNode()
+		this.snodes[level] = n
+	}
+
+	return n.sinsert(rem, qos, sub)
+}
+
+// This remove implementation ignores the QoS, as long as the subscriber
+// matches then it's removed
+func (this *snode) sremove(topic []byte, sub interface{}) error {
+	// If the topic is empty, it means we are at the final matching snode. If so,
+	// let's find the matching subscribers and remove them.
+	if len(topic) == 0 {
+		// If subscriber == nil, then it's signal to remove ALL subscribers
+		if sub == nil {
+			this.subs = this.subs[0:0]
+			this.qos = this.qos[0:0]
+			return nil
+		}
+
+		// If we find the subscriber then remove it from the list. Technically
+		// we just overwrite the slot by shifting all other items up by one.
+		for i := range this.subs {
+			if equal(this.subs[i], sub) {
+				this.subs = append(this.subs[:i], this.subs[i+1:]...)
+				this.qos = append(this.qos[:i], this.qos[i+1:]...)
+				return nil
+			}
+		}
+
+		return fmt.Errorf("No topic found for subscriber")
+	}
+
+	// Not the last level, so let's find the next level snode, and recursively
+	// call it's remove().
+
+	// ntl = next topic level
+	ntl, rem, err := nextTopicLevel(topic)
+	if err != nil {
+		return err
+	}
+
+	level := string(ntl)
+
+	// Find the snode that matches the topic level
+	n, ok := this.snodes[level]
+	if !ok {
+		return fmt.Errorf("No topic found")
+	}
+
+	// Remove the subscriber from the next level snode
+	if err := n.sremove(rem, sub); err != nil {
+		return err
+	}
+
+	// If there are no more subscribers and snodes to the next level we just visited
+	// let's remove it
+	if len(n.subs) == 0 && len(n.snodes) == 0 {
+		delete(this.snodes, level)
+	}
+
+	return nil
+}
+
+// smatch() returns all the subscribers that are subscribed to the topic. Given a topic
+// with no wildcards (publish topic), it returns a list of subscribers that subscribes
+// to the topic. For each of the level names, it's a match
+// - if there are subscribers to '#', then all the subscribers are added to result set
+func (this *snode) smatch(topic []byte, qos byte, subs *[]interface{}, qoss *[]byte) error {
+	// If the topic is empty, it means we are at the final matching snode. If so,
+	// let's find the subscribers that match the qos and append them to the list.
+	if len(topic) == 0 {
+		this.matchQos(qos, subs, qoss)
+		return nil
+	}
+
+	// ntl = next topic level
+	ntl, rem, err := nextTopicLevel(topic)
+	if err != nil {
+		return err
+	}
+
+	level := string(ntl)
+
+	for k, n := range this.snodes {
+		// If the key is "#", then these subscribers are added to the result set
+		if k == MWC {
+			n.matchQos(qos, subs, qoss)
+		} else if k == SWC || k == level {
+			if err := n.smatch(rem, qos, subs, qoss); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+// retained message nodes
+type rnode struct {
+	// If this is the end of the topic string, then add retained messages here
+	msg *packets.PublishPacket
+	// Otherwise add the next topic level here
+	rnodes map[string]*rnode
+}
+
+func newRNode() *rnode {
+	return &rnode{
+		rnodes: make(map[string]*rnode),
+	}
+}
+
+func (this *rnode) rinsert(topic []byte, msg *packets.PublishPacket) error {
+	// If there's no more topic levels, that means we are at the matching rnode.
+	if len(topic) == 0 {
+		// Reuse the message if possible
+		if this.msg == nil {
+			this.msg = msg
+		}
+
+		return nil
+	}
+
+	// Not the last level, so let's find or create the next level snode, and
+	// recursively call it's insert().
+
+	// ntl = next topic level
+	ntl, rem, err := nextTopicLevel(topic)
+	if err != nil {
+		return err
+	}
+
+	level := string(ntl)
+
+	// Add snode if it doesn't already exist
+	n, ok := this.rnodes[level]
+	if !ok {
+		n = newRNode()
+		this.rnodes[level] = n
+	}
+
+	return n.rinsert(rem, msg)
+}
+
+// Remove the retained message for the supplied topic
+func (this *rnode) rremove(topic []byte) error {
+	// If the topic is empty, it means we are at the final matching rnode. If so,
+	// let's remove the buffer and message.
+	if len(topic) == 0 {
+		this.msg = nil
+		return nil
+	}
+
+	// Not the last level, so let's find the next level rnode, and recursively
+	// call it's remove().
+
+	// ntl = next topic level
+	ntl, rem, err := nextTopicLevel(topic)
+	if err != nil {
+		return err
+	}
+
+	level := string(ntl)
+
+	// Find the rnode that matches the topic level
+	n, ok := this.rnodes[level]
+	if !ok {
+		return fmt.Errorf("No topic found")
+	}
+
+	// Remove the subscriber from the next level rnode
+	if err := n.rremove(rem); err != nil {
+		return err
+	}
+
+	// If there are no more rnodes to the next level we just visited let's remove it
+	if len(n.rnodes) == 0 {
+		delete(this.rnodes, level)
+	}
+
+	return nil
+}
+
+// rmatch() finds the retained messages for the topic and qos provided. It's somewhat
+// of a reverse match compare to match() since the supplied topic can contain
+// wildcards, whereas the retained message topic is a full (no wildcard) topic.
+func (this *rnode) rmatch(topic []byte, msgs *[]*packets.PublishPacket) error {
+	// If the topic is empty, it means we are at the final matching rnode. If so,
+	// add the retained msg to the list.
+	if len(topic) == 0 {
+		if this.msg != nil {
+			*msgs = append(*msgs, this.msg)
+		}
+		return nil
+	}
+
+	// ntl = next topic level
+	ntl, rem, err := nextTopicLevel(topic)
+	if err != nil {
+		return err
+	}
+
+	level := string(ntl)
+
+	if level == MWC {
+		// If '#', add all retained messages starting this node
+		this.allRetained(msgs)
+	} else if level == SWC {
+		// If '+', check all nodes at this level. Next levels must be matched.
+		for _, n := range this.rnodes {
+			if err := n.rmatch(rem, msgs); err != nil {
+				return err
+			}
+		}
+	} else {
+		// Otherwise, find the matching node, go to the next level
+		if n, ok := this.rnodes[level]; ok {
+			if err := n.rmatch(rem, msgs); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func (this *rnode) allRetained(msgs *[]*packets.PublishPacket) {
+	if this.msg != nil {
+		*msgs = append(*msgs, this.msg)
+	}
+
+	for _, n := range this.rnodes {
+		n.allRetained(msgs)
+	}
+}
+
+const (
+	stateCHR byte = iota // Regular character
+	stateMWC             // Multi-level wildcard
+	stateSWC             // Single-level wildcard
+	stateSEP             // Topic level separator
+	stateSYS             // System level topic ($)
+)
+
+// Returns topic level, remaining topic levels and any errors
+func nextTopicLevel(topic []byte) ([]byte, []byte, error) {
+	s := stateCHR
+
+	for i, c := range topic {
+		switch c {
+		case '/':
+			if s == stateMWC {
+				return nil, nil, fmt.Errorf("Multi-level wildcard found in topic and it's not at the last level")
+			}
+
+			if i == 0 {
+				return []byte(SWC), topic[i+1:], nil
+			}
+
+			return topic[:i], topic[i+1:], nil
+
+		case '#':
+			if i != 0 {
+				return nil, nil, fmt.Errorf("Wildcard character '#' must occupy entire topic level")
+			}
+
+			s = stateMWC
+
+		case '+':
+			if i != 0 {
+				return nil, nil, fmt.Errorf("Wildcard character '+' must occupy entire topic level")
+			}
+
+			s = stateSWC
+
+		// case '$':
+		// 	if i == 0 {
+		// 		return nil, nil, fmt.Errorf("Cannot publish to $ topics")
+		// 	}
+
+		// 	s = stateSYS
+
+		default:
+			if s == stateMWC || s == stateSWC {
+				return nil, nil, fmt.Errorf("Wildcard characters '#' and '+' must occupy entire topic level")
+			}
+
+			s = stateCHR
+		}
+	}
+
+	// If we got here that means we didn't hit the separator along the way, so the
+	// topic is either empty, or does not contain a separator. Either way, we return
+	// the full topic
+	return topic, nil, nil
+}
+
+// The QoS of the payload messages sent in response to a subscription must be the
+// minimum of the QoS of the originally published message (in this case, it's the
+// qos parameter) and the maximum QoS granted by the server (in this case, it's
+// the QoS in the topic tree).
+//
+// It's also possible that even if the topic matches, the subscriber is not included
+// due to the QoS granted is lower than the published message QoS. For example,
+// if the client is granted only QoS 0, and the publish message is QoS 1, then this
+// client is not to be send the published message.
+func (this *snode) matchQos(qos byte, subs *[]interface{}, qoss *[]byte) {
+	for _, sub := range this.subs {
+		// If the published QoS is higher than the subscriber QoS, then we skip the
+		// subscriber. Otherwise, add to the list.
+		// if qos >= this.qos[i] {
+		*subs = append(*subs, sub)
+		*qoss = append(*qoss, qos)
+		// }
+	}
+}
+
+func equal(k1, k2 interface{}) bool {
+	if reflect.TypeOf(k1) != reflect.TypeOf(k2) {
+		return false
+	}
+
+	if reflect.ValueOf(k1).Kind() == reflect.Func {
+		return &k1 == &k2
+	}
+
+	if k1 == k2 {
+		return true
+	}
+
+	switch k1 := k1.(type) {
+	case string:
+		return k1 == k2.(string)
+
+	case int64:
+		return k1 == k2.(int64)
+
+	case int32:
+		return k1 == k2.(int32)
+
+	case int16:
+		return k1 == k2.(int16)
+
+	case int8:
+		return k1 == k2.(int8)
+
+	case int:
+		return k1 == k2.(int)
+
+	case float32:
+		return k1 == k2.(float32)
+
+	case float64:
+		return k1 == k2.(float64)
+
+	case uint:
+		return k1 == k2.(uint)
+
+	case uint8:
+		return k1 == k2.(uint8)
+
+	case uint16:
+		return k1 == k2.(uint16)
+
+	case uint32:
+		return k1 == k2.(uint32)
+
+	case uint64:
+		return k1 == k2.(uint64)
+
+	case uintptr:
+		return k1 == k2.(uintptr)
+	}
+
+	return false
+}

lib/topics/topics.go

@@ -0,0 +1,91 @@
+package topics
+
+import (
+	"fmt"
+
+	"github.com/eclipse/paho.mqtt.golang/packets"
+)
+
+const (
+	// MWC is the multi-level wildcard
+	MWC = "#"
+
+	// SWC is the single level wildcard
+	SWC = "+"
+
+	// SEP is the topic level separator
+	SEP = "/"
+
+	// SYS is the starting character of the system level topics
+	SYS = "$"
+
+	// Both wildcards
+	_WC = "#+"
+)
+
+var (
+	providers = make(map[string]TopicsProvider)
+)
+
+// TopicsProvider
+type TopicsProvider interface {
+	Subscribe(topic []byte, qos byte, subscriber interface{}) (byte, error)
+	Unsubscribe(topic []byte, subscriber interface{}) error
+	Subscribers(topic []byte, qos byte, subs *[]interface{}, qoss *[]byte) error
+	Retain(msg *packets.PublishPacket) error
+	Retained(topic []byte, msgs *[]*packets.PublishPacket) error
+	Close() error
+}
+
+func Register(name string, provider TopicsProvider) {
+	if provider == nil {
+		panic("topics: Register provide is nil")
+	}
+
+	if _, dup := providers[name]; dup {
+		panic("topics: Register called twice for provider " + name)
+	}
+
+	providers[name] = provider
+}
+
+func Unregister(name string) {
+	delete(providers, name)
+}
+
+type Manager struct {
+	p TopicsProvider
+}
+
+func NewManager(providerName string) (*Manager, error) {
+	p, ok := providers[providerName]
+	if !ok {
+		return nil, fmt.Errorf("session: unknown provider %q", providerName)
+	}
+
+	return &Manager{p: p}, nil
+}
+
+func (this *Manager) Subscribe(topic []byte, qos byte, subscriber interface{}) (byte, error) {
+	return this.p.Subscribe(topic, qos, subscriber)
+}
+
+func (this *Manager) Unsubscribe(topic []byte, subscriber interface{}) error {
+	return this.p.Unsubscribe(topic, subscriber)
+}
+
+func (this *Manager) Subscribers(topic []byte, qos byte, subs *[]interface{}, qoss *[]byte) error {
+	return this.p.Subscribers(topic, qos, subs, qoss)
+}
+
+func (this *Manager) Retain(msg *packets.PublishPacket) error {
+	return this.p.Retain(msg)
+}
+
+func (this *Manager) Retained(topic []byte, msgs *[]*packets.PublishPacket) error {
+	return this.p.Retained(topic, msgs)
+}
+
+func (this *Manager) Close() error {
+	return this.p.Close()
+}

logger/logger_test.go

@@ -6,7 +6,6 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-
 	"go.uber.org/zap"
 )
 

main.go

@@ -8,10 +8,11 @@ package main
 
 import (
 	"fmt"
-	"github.com/fhmq/hmq/broker"
 	"os"
 	"os/signal"
 	"runtime"
+
+	"github.com/fhmq/hmq/broker"
 )
 
 func main() {