pkg/transport: add 'IsClosedConnError'

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>

pkg/transport/listener.go

@@ -27,6 +27,7 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/coreos/etcd/pkg/tlsutil"
@@ -269,3 +270,12 @@ func ShallowCopyTLSConfig(cfg *tls.Config) *tls.Config {
 	}
 	return &ncfg
 }
+
+// IsClosedConnError returns true if the error is from closing listener, cmux.
+// copied from golang.org/x/net/http2/http2.go
+func IsClosedConnError(err error) bool {
+	// 'use of closed network connection' (Go <=1.8)
+	// 'use of closed file or network connection' (Go >1.8, internal/poll.ErrClosing)
+	// 'mux: listener closed' (cmux.ErrListenerClosed)
+	return err != nil && strings.Contains(err.Error(), "closed")
+}

pkg/transport/listener_test.go

@@ -274,3 +274,15 @@ func TestNewListenerTLSInfoSelfCert(t *testing.T) {
 	}
 	testNewListenerTLSInfoAccept(t, tlsinfo)
 }
+
+func TestIsClosedConnError(t *testing.T) {
+	l, err := NewListener("testsocket", "unix", nil)
+	if err != nil {
+		t.Errorf("error listening on unix socket (%v)", err)
+	}
+	l.Close()
+	_, err = l.Accept()
+	if !IsClosedConnError(err) {
+		t.Fatalf("expect true, got false (%v)", err)
+	}
+}