Add realtime gateway and simulator bridge

realtime-gateway/internal/gateway/server.go

@@ -0,0 +1,109 @@
+package gateway
+
+import (
+	"context"
+	"encoding/json"
+	"log/slog"
+	"net/http"
+	"time"
+
+	"realtime-gateway/internal/channel"
+	"realtime-gateway/internal/config"
+	"realtime-gateway/internal/plugin"
+	"realtime-gateway/internal/router"
+	"realtime-gateway/internal/session"
+)
+
+type Server struct {
+	cfg       config.Config
+	logger    *slog.Logger
+	httpSrv   *http.Server
+	channels  *channel.Manager
+	hub       *router.Hub
+	plugins   *plugin.Bus
+	sessions  *session.Manager
+	startedAt time.Time
+}
+
+func NewServer(cfg config.Config, logger *slog.Logger) (*Server, error) {
+	channels := channel.NewManager(8 * time.Hour)
+	hub := router.NewHub(cfg.Gateway.MaxLatestStateEntries)
+	plugins := plugin.NewBus(logger.With("component", "plugin-bus"))
+	sessions := session.NewManager()
+
+	mux := http.NewServeMux()
+	server := &Server{
+		cfg:       cfg,
+		logger:    logger,
+		channels:  channels,
+		hub:       hub,
+		plugins:   plugins,
+		sessions:  sessions,
+		startedAt: time.Now(),
+		httpSrv: &http.Server{
+			Addr:         cfg.Server.HTTPListen,
+			ReadTimeout:  cfg.Server.ReadTimeout(),
+			WriteTimeout: cfg.Server.WriteTimeout(),
+			IdleTimeout:  cfg.Server.IdleTimeout(),
+		},
+	}
+
+	mux.HandleFunc("/healthz", server.handleHealth)
+	mux.HandleFunc("/metrics", server.handleMetrics)
+	mux.HandleFunc("/ws", server.handleWS)
+	server.registerChannelRoutes(mux)
+	if err := server.registerAdminRoutes(mux); err != nil {
+		return nil, err
+	}
+	server.httpSrv.Handler = mux
+	return server, nil
+}
+
+func (s *Server) Run(ctx context.Context) error {
+	errCh := make(chan error, 1)
+	go func() {
+		s.logger.Info("gateway listening", "addr", s.cfg.Server.HTTPListen)
+		errCh <- s.httpSrv.ListenAndServe()
+	}()
+
+	select {
+	case <-ctx.Done():
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), s.cfg.Server.ShutdownTimeout())
+		defer cancel()
+		s.logger.Info("shutting down gateway")
+		return s.httpSrv.Shutdown(shutdownCtx)
+	case err := <-errCh:
+		if err == http.ErrServerClosed {
+			return nil
+		}
+		return err
+	}
+}
+
+func (s *Server) handleHealth(w http.ResponseWriter, _ *http.Request) {
+	writeJSON(w, http.StatusOK, map[string]any{
+		"status": "ok",
+	})
+}
+
+func (s *Server) handleMetrics(w http.ResponseWriter, _ *http.Request) {
+	subscriberCount, latestStateCount := s.hub.Stats()
+	writeJSON(w, http.StatusOK, map[string]any{
+		"sessions":        s.sessions.Count(),
+		"subscribers":     subscriberCount,
+		"latestState":     latestStateCount,
+		"pluginHandlers":  s.plugins.HandlerCount(),
+		"httpListen":      s.cfg.Server.HTTPListen,
+		"anonymousClient": s.cfg.Auth.AllowAnonymousConsumers,
+	})
+}
+
+func (s *Server) handleWS(w http.ResponseWriter, r *http.Request) {
+	serveClient(w, r, s.logger, s.cfg, s.hub, s.channels, s.plugins, s.sessions)
+}
+
+func writeJSON(w http.ResponseWriter, status int, value any) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(value)
+}