不要なコードを削除

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"
)

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

type wsclient struct {
	roomID string
	id     string
	conn   *websocket.Conn
}

func (c wsclient) sender(snd <-chan wsMessage, unregister chan<- wsclient) {
	defer func() {
		c.conn.Close()
		unregister<- c
	}()

	for msg := range snd {
		if err := c.conn.WriteMessage(msg.messageType, msg.payload); err != nil {
			log.Debug().Err(err).Msg("c.conn.WriteMessage")
			return
		}
	}
}

func (c wsclient) reciever(ctx context.Context, rdb *redis.Client, unregister chan<- wsclient) {
	defer func() {
		c.conn.Close()
		unregister<- c
	}()

	for {
		_, p, err := c.conn.ReadMessage()
		if err != nil {
			log.Debug().Err(err).Msg("c.conn.ReadMessage")
			return
		}

		payload := append([]byte(c.roomID+"@"+c.id+"@"), p...)
		if err := rdb.Publish(ctx, "sdp", payload).Err(); err != nil {
			log.Debug().Err(err).Msg("rdb.Publish")
			return
		}
	}
}

type wsMessage struct {
	messageType int
	payload     []byte
}

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

type registrar chan<- wsclient

var i = 0

func (r registrar) registerWebsocket(c echo.Context) error {
	i++
	w := c.Response()
	req := c.Request()
	roomID := c.Param("id")

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

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

	return nil
}

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) registrar {
	register := make(chan wsclient)
	rdb := redis.NewClient(&redis.Options{Addr: "localhost:6379", Password: "", DB: 0})

	go func() {
		rooms := make(map[string]map[string]chan<- wsMessage)
		sub := rdb.Subscribe(ctx, "sdp")
		unregister := make(chan wsclient)

		for {
			select {
			case client := <-unregister:
				if _, ok := rooms[client.roomID]; !ok {
					continue
				}

				if _, ok := rooms[client.roomID][client.id]; !ok {
					continue
				}

				close(rooms[client.roomID][client.id])
				delete(rooms[client.roomID], client.id)

				if len(rooms[client.roomID]) == 0 {
					delete(rooms, client.roomID)
				}

			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 client.sender(snd, unregister)
				go client.reciever(ctx, rdb, unregister)


			case rmsg := <-sub.Channel():
				roomID, payload, err := parseRedisPayload(rmsg.Payload)
				if err != nil {
					return
				}
				for _, snd := range rooms[roomID] {
					snd <- wsMessage{messageType: websocket.TextMessage, payload: []byte(payload)}
				}
			}
		}
	} ()

	return registrar(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()

	r := 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", r.registerWebsocket)

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

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