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| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "embed" |
| 6 | + "encoding/json" |
| 7 | + "errors" |
| 8 | + "fmt" |
| 9 | + "log" |
| 10 | + "log/slog" |
| 11 | + "net/http" |
| 12 | + "strings" |
| 13 | + "time" |
| 14 | + |
| 15 | + "math/rand" |
| 16 | + |
| 17 | + "github.com/nidorx/chain" |
| 18 | + "github.com/nidorx/chain/pubsub" |
| 19 | + "github.com/nidorx/chain/socket" |
| 20 | +) |
| 21 | + |
| 22 | +var ( |
| 23 | + //go:embed public |
| 24 | + staticFs embed.FS |
| 25 | + staticDir = "public" |
| 26 | + lastPortUsed = 8080 |
| 27 | + cluster = map[int]*http.Server{} |
| 28 | +) |
| 29 | + |
| 30 | +func main() { |
| 31 | + |
| 32 | + // Used by session |
| 33 | + if err := chain.SetSecretKeyBase("ZcbD0D29eYsGq89QjirJbPkw7Qxwxboy"); err != nil { |
| 34 | + panic(err) |
| 35 | + } |
| 36 | + |
| 37 | + initPublisher() |
| 38 | + |
| 39 | + router := chain.New() |
| 40 | + router.GET("/*", createStaticFileHandler()) |
| 41 | + router.GET("/node", listNodeHandler) |
| 42 | + router.POST("/node", addNodeHandler) |
| 43 | + router.DELETE("/node", deleteNodeHandler) |
| 44 | + socket.ClientJsHandler(router, "/") // "/chain.js" |
| 45 | + |
| 46 | + port := fmt.Sprintf("%d", lastPortUsed) |
| 47 | + log.Printf("Listening on :%s...\n", port) |
| 48 | + |
| 49 | + if err := http.ListenAndServe(fmt.Sprintf(":%s", port), router); err != nil { |
| 50 | + log.Fatalf("ListenAndServe: %v", err) |
| 51 | + } |
| 52 | +} |
| 53 | + |
| 54 | +func initPublisher() { |
| 55 | + // send message to all nodes, using pubsub (local) |
| 56 | + go func() { |
| 57 | + addNodeHandler(nil) // first socket server |
| 58 | + addNodeHandler(nil) // second socket server |
| 59 | + |
| 60 | + ticker := time.NewTicker(500 * time.Millisecond) |
| 61 | + i := 1 |
| 62 | + for range ticker.C { |
| 63 | + i++ |
| 64 | + if bytes, err := json.Marshal(map[string]any{"name": "Server", "body": fmt.Sprintf("msg %d", i)}); err != nil { |
| 65 | + return |
| 66 | + } else { |
| 67 | + pubsub.Broadcast("chat:lobby", bytes) |
| 68 | + } |
| 69 | + } |
| 70 | + }() |
| 71 | +} |
| 72 | + |
| 73 | +func deleteNodeHandler(ctx *chain.Context) { |
| 74 | + if len(cluster) > 0 { |
| 75 | + for { |
| 76 | + toRemove := 0 |
| 77 | + for port := range cluster { |
| 78 | + if rand.Intn(100) > 50 { |
| 79 | + toRemove = port |
| 80 | + break |
| 81 | + } |
| 82 | + } |
| 83 | + if toRemove > 0 { |
| 84 | + sctx, _ := context.WithTimeout(context.Background(), 5*time.Second) |
| 85 | + if err := cluster[toRemove].Shutdown(sctx); err != nil { |
| 86 | + cluster[toRemove].Close() |
| 87 | + } |
| 88 | + delete(cluster, toRemove) |
| 89 | + break |
| 90 | + } |
| 91 | + } |
| 92 | + } |
| 93 | + ctx.OK() |
| 94 | +} |
| 95 | + |
| 96 | +func listNodeHandler(ctx *chain.Context) { |
| 97 | + var nodes []int |
| 98 | + for port, _ := range cluster { |
| 99 | + nodes = append(nodes, port) |
| 100 | + } |
| 101 | + ctx.Json(nodes) |
| 102 | +} |
| 103 | + |
| 104 | +func addNodeHandler(ctx *chain.Context) { |
| 105 | + lastPortUsed++ |
| 106 | + port := fmt.Sprintf("%d", lastPortUsed) |
| 107 | + |
| 108 | + channel := socket.NewChannel("chat:*", func(channel *socket.Channel) { |
| 109 | + |
| 110 | + channel.Join("chat:lobby", func(payload any, skt *socket.Socket) (reply any, err error) { |
| 111 | + slog.Info( |
| 112 | + skt.Topic()+" join", |
| 113 | + slog.String("server", port), |
| 114 | + slog.Any("socket", skt.Id()), |
| 115 | + slog.Any("payload", payload), |
| 116 | + ) |
| 117 | + return |
| 118 | + }) |
| 119 | + |
| 120 | + channel.Leave("chat:lobby", func(skt *socket.Socket, reason socket.LeaveReason) { |
| 121 | + slog.Info( |
| 122 | + skt.Topic()+" leave", |
| 123 | + slog.String("server", port), |
| 124 | + slog.Any("socket", skt.Id()), |
| 125 | + slog.Any("reason", reason), |
| 126 | + ) |
| 127 | + }) |
| 128 | + |
| 129 | + // automatically send messages to connected clients (from pubsub) |
| 130 | + channel.Subscribe("chat:*", "message") |
| 131 | + }) |
| 132 | + |
| 133 | + handler := &socket.Handler{ |
| 134 | + Channels: []*socket.Channel{channel}, |
| 135 | + OnConfig: func(handler *socket.Handler, router *chain.Router, endpoint string) error { |
| 136 | + return nil |
| 137 | + }, |
| 138 | + OnConnect: func(info *socket.Session) error { |
| 139 | + return nil |
| 140 | + }, |
| 141 | + Transports: []socket.Transport{&socket.TransportSSE{ |
| 142 | + Cors: &socket.CorsConfig{ |
| 143 | + MaxAge: 12 * time.Hour, |
| 144 | + AllowAllOrigins: false, |
| 145 | + AllowCredentials: true, |
| 146 | + AllowPrivateNetwork: false, |
| 147 | + AllowOrigins: []string{"*"}, |
| 148 | + AllowMethods: []string{"GET", "POST", "OPTIONS"}, |
| 149 | + AllowHeaders: []string{"Origin", "Content-Length", "Content-Type"}, |
| 150 | + ExposeHeaders: []string{}, |
| 151 | + }, |
| 152 | + }}, |
| 153 | + } |
| 154 | + |
| 155 | + // configure socket server |
| 156 | + router := chain.New() |
| 157 | + router.Configure("/socket", handler) |
| 158 | + |
| 159 | + server := &http.Server{ |
| 160 | + Addr: fmt.Sprintf(":%s", port), |
| 161 | + Handler: router, |
| 162 | + } |
| 163 | + |
| 164 | + go func() { |
| 165 | + log.Printf("Socket listening on :%s...\n", port) |
| 166 | + if err := server.ListenAndServe(); !errors.Is(err, http.ErrServerClosed) { |
| 167 | + log.Fatalf("Socket HTTP server error: %v", err) |
| 168 | + } |
| 169 | + }() |
| 170 | + |
| 171 | + cluster[lastPortUsed] = server |
| 172 | + |
| 173 | + if ctx != nil { |
| 174 | + ctx.OK() |
| 175 | + } |
| 176 | +} |
| 177 | + |
| 178 | +func createStaticFileHandler() http.Handler { |
| 179 | + h := http.FileServer(http.FS(staticFs)) |
| 180 | + return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| 181 | + if r.URL.Path == "/" { |
| 182 | + r.URL.Path = fmt.Sprintf("/%s/", staticDir) |
| 183 | + } else { |
| 184 | + b := strings.Split(r.URL.Path, "/")[0] |
| 185 | + if b != staticDir { |
| 186 | + r.URL.Path = fmt.Sprintf("/%s%s", staticDir, r.URL.Path) |
| 187 | + } |
| 188 | + } |
| 189 | + h.ServeHTTP(w, r) |
| 190 | + }) |
| 191 | +} |
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