tcp echo server

main.go

@@ -0,0 +1,100 @@
+package main
+
+import (
+	"context"
+	"net"
+	"os"
+	"os/signal"
+	"serveg/common/log"
+	"strconv"
+	"syscall"
+	"time"
+)
+
+func main() {
+	os.Exit(run())
+}
+
+// main with int return value
+func run() int {
+	defer log.Defer()
+	log.StartGoroutine()
+	logger := log.LoggerContext{Name: "main"}
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	//defer stop()
+
+	conf, err := ParseOrCreateDefault()
+	if err != nil {
+		logger.Error(err)
+		return 1
+	}
+
+	errCh := make(chan error, 1)
+	go func() { errCh <- server(conf) }()
+	logger.Info("server started")
+
+	select {
+	// server failed to start
+	case err := <-errCh:
+		logger.Error(err)
+		return 1
+	// got SIGINT/SIGTERM
+	case <-ctx.Done():
+		stop() // restore default behaviour: a second Ctrl+C kills immediately
+		logger.Info("shutting down")
+	}
+
+	return 0
+}
+
+func server(conf *Config) error {
+	logger := log.LoggerContext{Name: "server"}
+	addr := net.JoinHostPort(conf.Ip.String(), strconv.Itoa(int(conf.Port)))
+
+	logger.Info("listening at", addr)
+	srv, err := net.Listen("tcp", addr)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = srv.Close() }()
+
+	for i := int64(0); ; i++ {
+		conn, err := srv.Accept()
+		if err != nil {
+			logger.Warn(err)
+			continue
+		}
+		go handleConnection(conn, i)
+	}
+}
+
+func handleConnection(conn net.Conn, n int64) {
+	logger := log.LoggerContext{Name: "conn-" + strconv.FormatInt(n, 10)}
+	defer func() {
+		if r := recover(); r != nil {
+			logger.Error("panic: ", r)
+		}
+		_ = conn.Close()
+	}()
+
+	buf := make([]byte, 4096)
+
+	for {
+		if err := conn.SetDeadline(time.Now().Add(30 * time.Second)); err != nil {
+			logger.Warn(err)
+			break
+		}
+		n, err := conn.Read(buf)
+		if err != nil {
+			logger.Warn(err)
+			break
+		}
+		msgBytes := buf[:n]
+		logger.Info("msg: `", string(msgBytes), "`")
+		if _, err := conn.Write(msgBytes); err != nil {
+			logger.Warn(err)
+			break
+		}
+	}
+}