Adding more replication data to INFO response

internal/server/client.go

@@ -17,6 +17,7 @@ import (
 // Client is an remote connection into to Tile38
 type Client struct {
 	id         int              // unique id
+	replPort   int              // the known replication port for follower connections
 	authd      bool             // client has been authenticated
 	outputType Type             // Null, JSON, or RESP
 	remoteAddr string           // original remote address

internal/server/follow.go

@@ -96,6 +96,41 @@ func (c *Server) cmdFollow(msg *Message) (res resp.Value, err error) {
 	return OKMessage(msg, start), nil
 }
 
+// cmdReplConf is a command handler that sets replication configuration info
+func (c *Server) cmdReplConf(msg *Message, client *Client) (res resp.Value, err error) {
+	start := time.Now()
+	vs := msg.Args[1:]
+	var ok bool
+	var cmd, val string
+
+	// Parse the message
+	if vs, cmd, ok = tokenval(vs); !ok || cmd == "" {
+		return NOMessage, errInvalidNumberOfArguments
+	}
+	if vs, val, ok = tokenval(vs); !ok || val == "" {
+		return NOMessage, errInvalidNumberOfArguments
+	}
+
+	// Switch on the command received
+	switch cmd {
+	case "listening-port":
+		// Parse the port as an integer
+		port, err := strconv.Atoi(val)
+		if err != nil {
+			return NOMessage, errInvalidArgument(val)
+		}
+
+		// Apply the replication port to the client and return
+		for _, c := range c.conns {
+			if c.remoteAddr == client.remoteAddr {
+				c.replPort = port
+				return OKMessage(msg, start), nil
+			}
+		}
+	}
+	return NOMessage, fmt.Errorf("cannot find follower")
+}
+
 func doServer(conn *RESPConn) (map[string]string, error) {
 	v, err := conn.Do("server")
 	if err != nil {
@@ -191,7 +226,22 @@ func (c *Server) followStep(host string, port int, followc int) error {
 		return err
 	}
 
-	v, err := conn.Do("aof", pos)
+	// Send the replication port to the leader
+	v, err := conn.Do("replconf", "listening-port", c.port)
+	if err != nil {
+		return err
+	}
+	if v.Error() != nil {
+		return v.Error()
+	}
+	if v.String() != "OK" {
+		return errors.New("invalid response to replconf request")
+	}
+	if core.ShowDebugMessages {
+		log.Debug("follow:", addr, ":replconf")
+	}
+
+	v, err = conn.Do("aof", pos)
 	if err != nil {
 		return err
 	}

internal/server/server.go

@@ -970,7 +970,7 @@ func (server *Server) handleInputCommand(client *Client, msg *Message) error {
 		if server.config.followHost() != "" && !server.fcuponce {
 			return writeErr("catching up to leader")
 		}
-	case "follow", "readonly", "config":
+	case "follow", "slaveof", "replconf", "readonly", "config":
 		// system operations
 		// does not write to aof, but requires a write lock.
 		server.mu.Lock()
@@ -1081,7 +1081,6 @@ func (server *Server) command(msg *Message, client *Client) (
 		res, d, err = server.cmdRename(msg, false)
 	case "renamenx":
 		res, d, err = server.cmdRename(msg, true)
-
 	case "sethook":
 		res, d, err = server.cmdSetHook(msg, false)
 	case "delhook":
@@ -1090,7 +1089,6 @@ func (server *Server) command(msg *Message, client *Client) (
 		res, d, err = server.cmdPDelHook(msg, false)
 	case "hooks":
 		res, err = server.cmdHooks(msg, false)
-
 	case "setchan":
 		res, d, err = server.cmdSetHook(msg, true)
 	case "delchan":
@@ -1099,7 +1097,6 @@ func (server *Server) command(msg *Message, client *Client) (
 		res, d, err = server.cmdPDelHook(msg, true)
 	case "chans":
 		res, err = server.cmdHooks(msg, true)
-
 	case "expire":
 		res, d, err = server.cmdExpire(msg)
 	case "persist":
@@ -1124,8 +1121,10 @@ func (server *Server) command(msg *Message, client *Client) (
 			return
 		}
 		res, err = server.cmdSleep(msg)
-	case "follow":
+	case "follow", "slaveof":
 		res, err = server.cmdFollow(msg)
+	case "replconf":
+		res, err = server.cmdReplConf(msg, client)
 	case "readonly":
 		res, err = server.cmdReadOnly(msg)
 	case "stats":

internal/server/stats.go

@@ -352,9 +352,27 @@ func (c *Server) writeInfoStats(w *bytes.Buffer) {
 	fmt.Fprintf(w, "total_commands_processed:%d\r\n", c.statsTotalCommands.get()) // Total number of commands processed by the server
 	fmt.Fprintf(w, "expired_keys:%d\r\n", c.statsExpired.get())                   // Total number of key expiration events
 }
+
+// writeInfoReplication writes all replication data to the 'info' response
 func (c *Server) writeInfoReplication(w *bytes.Buffer) {
+	if c.config.followHost() != "" {
+		fmt.Fprintf(w, "role:slave\r\n")
+		fmt.Fprintf(w, "master_host:%s\r\n", c.config.followHost())
+		fmt.Fprintf(w, "master_port:%v\r\n", c.config.followPort())
+	} else {
+		fmt.Fprintf(w, "role:master\r\n")
+		var i int
+		for _, cc := range c.conns {
+			if cc.replPort != 0 {
+				fmt.Fprintf(w, "slave%v:ip=%s,port=%v,state=online\r\n", i,
+					strings.Split(cc.remoteAddr, ":")[0], cc.replPort)
+				i++
+			}
+		}
+	}
 	fmt.Fprintf(w, "connected_slaves:%d\r\n", len(c.aofconnM)) // Number of connected slaves
 }
+
 func (c *Server) writeInfoCluster(w *bytes.Buffer) {
 	fmt.Fprintf(w, "cluster_enabled:0\r\n")
 }