feat(sense): complete T-006 five-stream integration

Sense/cmd/rtsp-fault-proxy/main.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io"
+	"log/slog"
+	"net"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+)
+
+func main() {
+	listenAddress := flag.String("listen", "127.0.0.1:10554", "local listen address")
+	upstreamAddress := flag.String("upstream", "", "upstream host:port")
+	flag.Parse()
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
+	if *upstreamAddress == "" {
+		logger.Error("upstream is required")
+		os.Exit(2)
+	}
+	if _, _, err := net.SplitHostPort(*upstreamAddress); err != nil {
+		logger.Error("upstream must be host:port")
+		os.Exit(2)
+	}
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+	if err := serve(ctx, *listenAddress, *upstreamAddress); err != nil {
+		logger.Error("RTSP fault proxy stopped", "error", err)
+		os.Exit(1)
+	}
+}
+
+func serve(ctx context.Context, listenAddress, upstreamAddress string) error {
+	listener, err := net.Listen("tcp", listenAddress)
+	if err != nil {
+		return fmt.Errorf("listen: %w", err)
+	}
+	defer listener.Close()
+	go func() {
+		<-ctx.Done()
+		_ = listener.Close()
+	}()
+	var connections sync.WaitGroup
+	defer connections.Wait()
+	for {
+		client, acceptErr := listener.Accept()
+		if acceptErr != nil {
+			if ctx.Err() != nil {
+				return nil
+			}
+			return fmt.Errorf("accept: %w", acceptErr)
+		}
+		connections.Add(1)
+		go func() {
+			defer connections.Done()
+			proxy(client, upstreamAddress)
+		}()
+	}
+}
+
+func proxy(client net.Conn, upstreamAddress string) {
+	defer client.Close()
+	upstream, err := net.DialTimeout("tcp", upstreamAddress, 5*time.Second)
+	if err != nil {
+		return
+	}
+	defer upstream.Close()
+	done := make(chan struct{}, 2)
+	copyOneWay := func(destination, source net.Conn) {
+		_, _ = io.Copy(destination, source)
+		done <- struct{}{}
+	}
+	go copyOneWay(upstream, client)
+	go copyOneWay(client, upstream)
+	<-done
+}