redisを使うようにした

main.go

package main

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"time"

	"github.com/go-redis/redis/v8"
	"github.com/gorilla/websocket"
	"github.com/labstack/echo/v4"

	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	"github.com/rs/zerolog/pkgerrors"
)

const (
	// Time allowed to write a message to the peer.
	writeWait = 10 * time.Second

	// Time allowed to read the next pong message from the peer.
	pongWait = 60 * time.Second

	// Send pings to peer with this period. Must be less than pongWait.
	pingPeriod = (pongWait * 9) / 10

	// Maximum message size allowed from peer.
	maxMessageSize = 512
)

var upgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
}

type wsclient struct {
	roomID string
	id     string
	conn   *websocket.Conn
	msg    chan<- message
}

type wsMessage struct {
	messageType int
	payload     []byte
}

type message struct {
	roomID   string
	clientID string
	wsMessage
	err error
}

func (c wsclient) reciever() {
	defer c.conn.Close()

	c.conn.SetReadLimit(maxMessageSize)
	c.conn.SetReadDeadline(time.Now().Add(pongWait))
	c.conn.SetPongHandler(func(string) error { c.conn.SetReadDeadline(time.Now().Add(pongWait)); return nil })

	for {
		mt, p, err := c.conn.ReadMessage()
		if err != nil {
			c.msg <- message{roomID: c.roomID, clientID: c.id, err: err}
			return
		}

		c.msg <- message{roomID: c.roomID, clientID: c.id, wsMessage: wsMessage{messageType: mt, payload: p}, err: nil}
	}

}

func (c wsclient) runSender() chan<- wsMessage {
	snd := make(chan wsMessage)

	go func() {
		ticker := time.NewTicker(pingPeriod)

		defer func() {
			c.conn.Close()
			ticker.Stop()
		}()

		for {
			select {
			case <-ticker.C:
				c.conn.SetWriteDeadline(time.Now().Add(writeWait))
				if err := c.conn.WriteMessage(websocket.PingMessage, nil); err != nil {
					c.msg <- message{clientID: c.id, err: err}
					return
				}

			case m, ok := <-snd:
				if !ok {
					return
				}

				log.Debug().Str("clientID", c.id).Str("message", string(m.payload)).Msg("write")
				if err := c.conn.WriteMessage(m.messageType, m.payload); err != nil {
					c.msg <- message{roomID: c.roomID, clientID: c.id, err: err}
					return
				}
			}
		}
	}()

	return snd
}

func (c wsclient) connect(msg chan<- message) chan<- wsMessage {
	c.msg = msg
	go c.reciever()
	snd := c.runSender()
	return snd
}

func runEchoServer(ctx context.Context) chan<- wsclient {
	register := make(chan wsclient)

	go func() {
		snds := make(map[string]map[string]chan<- wsMessage)
		msg := make(chan message)

		for {
			select {
			case <-ctx.Done():
				return

			case client := <-register:
				log.Debug().Str("roomID", client.roomID).Str("clientID", client.id).Msg("register")
				snd := client.connect(msg)
				if _, ok := snds[client.roomID]; !ok {
					snds[client.roomID] = make(map[string]chan<- wsMessage)
				}
				snds[client.roomID][client.id] = snd

			case m := <-msg:
				log.Debug().Msg(string(m.payload))

				if m.err != nil {
					log.Debug().Err(m.err).Msg("")
					if _, ok := snds[m.roomID]; !ok {
						continue
					}
					if _, ok := snds[m.roomID][m.clientID]; !ok {
						continue
					}

					close(snds[m.roomID][m.clientID])
					delete(snds[m.roomID], m.clientID)
					if len(snds[m.roomID]) == 0 {
						delete(snds, m.roomID)
					}

					continue
				}

				for id, snd := range snds[m.roomID] {
					log.Debug().Str("clientID", id).Str("message", string(m.payload)).Msg("send")
					snd <- wsMessage{messageType: m.messageType, payload: m.payload}
				}
			}
		}
	}()

	return register
}

func hub(registrar chan<- wsclient) func(c echo.Context) error {
	i := 0
	return func(c echo.Context) error {
		i++
		w := c.Response()
		r := c.Request()
		roomID := c.Param("id")

		conn, err := upgrader.Upgrade(w, r, nil)
		if err != nil {
			return err
		}

		registrar <- wsclient{roomID: roomID, id: fmt.Sprintf("hello%d", i), conn: conn}

		return nil
	}
}

func (c wsclient) sender(snd <-chan message, msg chan<- message) {
	defer c.conn.Close()
	for {
		select {
		case m, ok := <-snd:
			if !ok {
				return
			}
			err := c.conn.WriteMessage(m.messageType, m.payload)
			if err != nil {
				msg <- message{roomID: c.roomID, clientID: c.id, err: err}
			}
		}
	}
}

func parseRedisPayload(p string) (string, string, error) {
	i := strings.Index(p, "@")
	if i < 1 {
		return "", "", errors.New("no room id")
	}

	roomID := p[:i]
	rest := p[i+1:]

	return roomID, rest, nil
}


func runPubSub(ctx context.Context) chan<- wsclient {
	register := make(chan wsclient)
	rdb := redis.NewClient(&redis.Options{Addr: "localhost:6379", Password: "", DB: 0})

	subscriber := func () {
		rooms := make(map[string]map[string]chan<-wsMessage)
		sub := rdb.Subscribe(ctx, "sdp")
		for {
			select {
			case client := <-register:
				if _, ok := rooms[client.roomID]; !ok {
					rooms[client.roomID] = make(map[string]chan<-wsMessage)
				}
				snd := make(chan wsMessage)
				rooms[client.roomID][client.id] = snd
				go func(conn *websocket.Conn, snd <-chan wsMessage) {
					for {
						select {
						case msg := <-snd:
							log.Debug().Str("goroutine", "sender").Msg("conn.WriteMessage")
							conn.WriteMessage(msg.messageType, msg.payload)
						}
					}
				}(client.conn, snd)

				go func(roomID, clientID string, conn *websocket.Conn) {
					log.Debug().Str("goroutine", "reciever").Msg("begin")
					defer log.Debug().Str("goroutine", "reciever").Msg("end")
					for {
						_, p, err := conn.ReadMessage()
						if err != nil {
							log.Error().Err(err).Msg("conn.ReadMessage")
							return
						}
						payload := append([]byte(roomID + "@" + clientID + "@"), p...)
						log.Debug().Str("goroutine", "reciever").Str("payload", string(payload)).Msg("publish")
						err = rdb.Publish(ctx, "sdp", payload).Err()
						if err != nil {
							log.Error().Err(err).Msg("rdb.Publish")
							return
						}
					}
				}(client.roomID, client.id, client.conn)


			case rmsg := <-sub.Channel():
				log.Debug().Str("goroutine","subscriber").Str("payload", rmsg.Payload).Msg("recieve subscribed msg")
				roomID, payload, err := parseRedisPayload(rmsg.Payload)
				if err != nil {
					log.Error().Err(err).Str("payload", rmsg.Payload).Msg("parseRedisMessage")
					return
				}
				for _, snd := range rooms[roomID] {
					snd<- wsMessage{messageType: websocket.TextMessage, payload: []byte(payload)}
				}
			}
		}
	}

	go subscriber()

	return register
}


func main() {
	zerolog.TimeFieldFormat = time.RFC3339Nano
	zerolog.ErrorStackMarshaler = pkgerrors.MarshalStack
	zerolog.SetGlobalLevel(zerolog.DebugLevel)

	e := echo.New()

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// registrar := runEchoServer(ctx)
	registrar := runPubSub(ctx)

	e.HTTPErrorHandler = func(err error, c echo.Context) {
		log.Debug().Err(err).Msg(fmt.Sprintf("%+v", err))
		e.DefaultHTTPErrorHandler(err, c)
	}

	// e.GET("/rooms/:id/ws", hub(registrar))
	e.GET("/rooms/:id/ws", hub(registrar))

	e.Static("/", "./web")

	e.Logger.Fatal(e.Start(":8080"))
}