network/graceful.go made redundant

The call to http.Server.Shutdown in main.go that happens on os.Interrupt
closes listeners. Remove racey code and format network/network.go.

Running Listener.Accept in a loop is not necessary as the stdlib expects
SA_RESTART to be set for signal handlers.

network/graceful.go

@@ -1,61 +0,0 @@
-package network
-
-import (
-	"errors"
-	"net"
-)
-
-var ErrListenerStopped = errors.New("listener was stopped")
-
-// GracefulListener provides safe and graceful net.Listener wrapper that prevents error on graceful shutdown
-type GracefulListener struct {
-	listener net.Listener
-	stop     chan int
-}
-
-// Accept method
-func (l *GracefulListener) Accept() (net.Conn, error) {
-	for {
-		c, err := l.listener.Accept()
-		select {
-		case <-l.stop:
-			if c != nil {
-				c.Close()
-			}
-			close(l.stop)
-			l.stop = nil
-			return nil, ErrListenerStopped
-		default:
-
-		}
-		if err != nil {
-			neterr, ok := err.(net.Error)
-			if ok && neterr.Timeout() && neterr.Temporary() {
-				continue
-			}
-		}
-		return c, err
-	}
-}
-
-// Close method
-func (l *GracefulListener) Close() (err error) {
-	l.listener.Close()
-	if l.stop != nil {
-		l.stop <- 0
-	}
-	return
-}
-
-// Addr method
-func (l *GracefulListener) Addr() net.Addr {
-	return l.listener.Addr()
-}
-
-// WrapListener wraps a net.Listener such that it can be closed gracefully
-func WrapListener(l net.Listener) net.Listener {
-	return &GracefulListener{
-		listener: l,
-		stop:     make(chan int),
-	}
-}

network/network.go

@@ -9,33 +9,27 @@ import (
 )
 
 // CreateHTTPListener creates a net.Listener for main http webapp given main config
-func CreateHTTPListener(conf *config.Config) (l net.Listener, err error) {
-	if conf.I2P == nil {
-		l, err = net.Listen("tcp", fmt.Sprintf("%s:%d", conf.Host, conf.Port))
-	} else {
+func CreateHTTPListener(conf *config.Config) (net.Listener, error) {
+	if conf.I2P != nil {
 		s := i2p.NewSession(conf.I2P.Name, conf.I2P.Addr, conf.I2P.Keyfile)
-		err = s.Open()
+		err := s.Open()
 		if s != nil {
 			log.Infof("i2p address: %s", s.B32Addr())
-			l = s
 		}
+		return s, err
 	}
-	if l != nil {
-		l = WrapListener(l)
-	}
-	return
+	return net.Listen("tcp", fmt.Sprintf("%s:%d", conf.Host, conf.Port))
 }
 
 // CreateScraperSocket creates a UDP Scraper socket
-func CreateScraperSocket(conf *config.Config) (pc net.PacketConn, err error) {
-	if conf.I2P == nil {
-		var laddr *net.UDPAddr
-		laddr, err = net.ResolveUDPAddr("udp", conf.Scrape.Addr)
-		if err == nil {
-			pc, err = net.ListenUDP("udp", laddr)
-		}
-	} else {
+func CreateScraperSocket(conf *config.Config) (net.PacketConn, error) {
+	if conf.I2P != nil {
 		log.Fatal("i2p udp scraper not supported")
 	}
-	return
+	var laddr *net.UDPAddr
+	laddr, err := net.ResolveUDPAddr("udp", conf.Scrape.Addr)
+	if err != nil {
+		return nil, err
+	}
+	return net.ListenUDP("udp", laddr)
 }