Added in detailed conn client logs

Created new data types to store the last time a message was received from a device along with publishing the last will topic, keepalive time, and credentials over the /connections topic. These were mirrored also over the REST API for synchronous stateful services starting up from a crashed k8s pod or other usecases. Start by subscribing to /connections/+ and then GET /api/v1/connections to get the open connections, if a device connects while you are setting up your state, your messageHandler will handle the setup since it has the same information. This information has been published over  for devices you don't have any control over and for relay purposes. You can take all of the device information and now create a faux client emulating your downstream device, this may sound strange; but I have a usecase for it, a lot of cheap chinese IoT's were not designed for mass production and we have to fix their messages in the cloud before relaying them to our other legacy servers

.gitignore

@@ -7,3 +7,7 @@ log/*
 .vscode/settings.json
 .pre-commit-config.yaml
 hmq.exe
+*.sw*
+*.swo
+*.swp
+*.swn

broker/broker.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"sync"
 	"time"
+	encJson "encoding/json"
 
 	"github.com/fhmq/hmq/broker/lib/sessions"
 	"github.com/fhmq/hmq/broker/lib/topics"
@@ -404,8 +405,19 @@ func (b *Broker) handleConnection(typ int, conn net.Conn) {
 			}
 		}
 		b.clients.Store(cid, c)
+		
+		pubInfo := Info{
+			ClientID: info.clientID,
+			Username: info.username,
+			Password: info.password,
+			Keepalive: info.keepalive,
+			WillMsg: &PubPacket{
+				TopicName: info.willMsg.TopicName,
+				Payload: info.willMsg.Payload,
+			},
+		}
 
-		b.OnlineOfflineNotification(cid, true)
+		b.OnlineOfflineNotification(pubInfo, true, c.lastMsgTime)
 		{
 			b.Publish(&bridge.Elements{
 				ClientID:  msg.ClientIdentifier,
@@ -695,11 +707,33 @@ func (b *Broker) BroadcastUnSubscribe(topicsToUnSubscribeFrom []string) {
 	b.BroadcastSubOrUnsubMessage(unsub)
 }
 
-func (b *Broker) OnlineOfflineNotification(clientID string, online bool) {
+type OnlineOfflineMsg struct {
+	ClientID	string		`json:"clientID"`
+	Online		bool		`json:"online"`
+	Timestamp	string		`json:"timestamp"`
+	ClientInfo	Info		`json:"info"`
+	LastMsgTime	int64		`json:"lastMsg"`
+}
+
+func (b *Broker) OnlineOfflineNotification(info Info, online bool, lastMsg int64) {
 	packet := packets.NewControlPacket(packets.Publish).(*packets.PublishPacket)
-	packet.TopicName = "$SYS/broker/connection/clients/" + clientID
+	packet.TopicName = "$SYS/broker/connection/clients/" + info.ClientID
 	packet.Qos = 0
-	packet.Payload = []byte(fmt.Sprintf(`{"clientID":"%s","online":%v,"timestamp":"%s"}`, clientID, online, time.Now().UTC().Format(time.RFC3339)))
+
+	msg := OnlineOfflineMsg{
+		ClientID: info.ClientID,
+		Online: online,
+		Timestamp: time.Now().UTC().Format(time.RFC3339),
+		ClientInfo: info,
+		LastMsgTime: lastMsg,
+	}
+
+	if b, err := encJson.Marshal(msg); err != nil {
+		//This is a TERRIBLE situation, falling back to legacy format to not break API Contract
+		packet.Payload = []byte(fmt.Sprintf(`{"clientID":"%s","online":%v,"timestamp":"%s"}`, info.ClientID, online, time.Now().UTC().Format(time.RFC3339)))
+	} else {
+		packet.Payload = b
+	}
 
 	b.PublishMessage(packet)
 }

broker/client.go

@@ -79,6 +79,7 @@ type client struct {
 	mqueue         *queue.Queue
 	retryTimer     *time.Timer
 	retryTimerLock sync.Mutex
+	lastMsgTime	int64
 }
 
 type InflightStatus uint8
@@ -111,6 +112,19 @@ type info struct {
 	remoteIP  string
 }
 
+type PubPacket struct {
+	TopicName	string			`json:"topicName"`
+	Payload		[]byte			`json:"payload"`
+}
+
+type Info struct {
+	ClientID  string			`json:"clientId"`
+	Username  string			`json:"username"`
+	Password  []byte			`json:"password"`
+	Keepalive uint16			`json:"keepalive"`
+	WillMsg   *PubPacket			`json:"willMsg"`
+}
+
 type route struct {
 	remoteID  string
 	remoteUrl string
@@ -122,6 +136,7 @@ var (
 )
 
 func (c *client) init() {
+	c.lastMsgTime = time.Now().Unix()		//mark the connection packet time as last time messaged
 	c.status = Connected
 	c.info.localIP, _, _ = net.SplitHostPort(c.conn.LocalAddr().String())
 	remoteAddr := c.conn.RemoteAddr()
@@ -185,6 +200,8 @@ func (c *client) readLoop() {
 			if _, isDisconnect := packet.(*packets.DisconnectPacket); isDisconnect {
 				c.info.willMsg = nil
 				c.cancelFunc()
+			} else {
+				c.lastMsgTime = time.Now().Unix()
 			}
 
 			msg := &Message{
@@ -842,8 +859,18 @@ func (c *client) Close() {
 
 	if c.typ == CLIENT {
 		b.BroadcastUnSubscribe(unSubTopics)
+		pubInfo := Info{
+			ClientID: c.info.clientID,
+			Username: c.info.username,
+			Password: c.info.password,
+			Keepalive: c.info.keepalive,
+			WillMsg: &PubPacket{
+				TopicName: c.info.willMsg.TopicName,
+				Payload: c.info.willMsg.Payload,
+			},
+		}
 		//offline notification
-		b.OnlineOfflineNotification(c.info.clientID, false)
+		b.OnlineOfflineNotification(pubInfo, false, c.lastMsgTime)
 	}
 
 	if c.info.willMsg != nil {

broker/http.go

@@ -8,9 +8,14 @@ const (
 	CONNECTIONS	= "api/v1/connections"
 )
 
+type ConnClient struct {
+	Info				`json:"info"`
+	LastMsgTime	int64		`json:"lastMsg"`
+}
+
 type resp struct {
 	Code	int		`json:"code,omitempty"`
-	Clients	[]string	`json:"clients,omitempty"`
+	Clients	[]ConnClient	`json:"clients,omitempty"`
 }
 
 func InitHTTPMoniter(b *Broker) {
@@ -29,9 +34,25 @@ func InitHTTPMoniter(b *Broker) {
 		c.JSON(200, &r)
 	})
 	router.GET(CONNECTIONS, func(c *gin.Context) {
-		conns := make([]string, 0)
+		conns := make([]ConnClient, 0)
 		b.clients.Range(func (k, v interface{}) bool {
-			conns = append(conns, v.(*client).info.clientID)
+			cl, _ := v.(*client)
+
+			msg := ConnClient{
+				Info: Info{
+					ClientID: cl.info.clientID,
+					Username: cl.info.username,
+					Password: cl.info.password,
+					Keepalive: cl.info.keepalive,
+					WillMsg: &PubPacket{
+						TopicName: cl.info.willMsg.TopicName,
+						Payload: cl.info.willMsg.Payload,
+					},
+				},
+				LastMsgTime: cl.lastMsgTime,
+			}
+
+			conns = append(conns, msg)
 			return true
 		})
 		r := resp{Clients: conns}