mount: fix --daemon failing when --rc is enabled - fixes #9196

Before this change the parent process kept the remote control and
metrics servers it started in initConfig listening, so the daemon child
could not bind the same addresses and exited.

After this change the parent shuts those servers down just before
daemonizing, and the child starts them as usual.

cmd/cmd.go

@@ -379,6 +379,27 @@ func StartStats() func() {
 	}
 }
 
+var (
+	rcServer      *rcserver.Server
+	metricsServer *rcserver.MetricsServer
+)
+
+// StopRemoteControl shuts down the remote control and metrics servers started by initConfig.
+func StopRemoteControl() {
+	if rcServer != nil {
+		if err := rcServer.Shutdown(); err != nil {
+			fs.Errorf(nil, "Failed to stop remote control: %v", err)
+		}
+		rcServer = nil
+	}
+	if metricsServer != nil {
+		if err := metricsServer.Shutdown(); err != nil {
+			fs.Errorf(nil, "Failed to stop metrics server: %v", err)
+		}
+		metricsServer = nil
+	}
+}
+
 // initConfig is run by cobra after initialising the flags
 func initConfig() {
 	// Set the global options from the flags
@@ -422,14 +443,14 @@ func initConfig() {
 	}
 
 	// Start the remote control server if configured
-	_, err = rcserver.Start(ctx, &rc.Opt)
+	rcServer, err = rcserver.Start(ctx, &rc.Opt)
 	if err != nil {
 		fs.Fatalf(nil, "Failed to start remote control: %v", err)
 	}
 
 	// Start the metrics server if configured and not running the "rc" command
 	if len(os.Args) >= 2 && os.Args[1] != "rc" {
-		_, err = rcserver.MetricsStart(ctx, &rc.Opt)
+		metricsServer, err = rcserver.MetricsStart(ctx, &rc.Opt)
 		if err != nil {
 			fs.Fatalf(nil, "Failed to start metrics server: %v", err)
 		}

cmd/cmd_test.go

@@ -0,0 +1,52 @@
+package cmd
+
+import (
+	"context"
+	"net"
+	"testing"
+
+	"github.com/rclone/rclone/fs/rc"
+	"github.com/rclone/rclone/fs/rc/rcserver"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func freeAddr(t *testing.T) string {
+	l, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+	addr := l.Addr().String()
+	require.NoError(t, l.Close())
+	return addr
+}
+
+func TestStopRemoteControl(t *testing.T) {
+	ctx := context.Background()
+	rcAddr, metricsAddr := freeAddr(t), freeAddr(t)
+	opt := rc.Opt
+	opt.Enabled = true
+	opt.HTTP.ListenAddr = []string{rcAddr}
+	opt.MetricsHTTP.ListenAddr = []string{metricsAddr}
+
+	var err error
+	rcServer, err = rcserver.Start(ctx, &opt)
+	require.NoError(t, err)
+	metricsServer, err = rcserver.MetricsStart(ctx, &opt)
+	require.NoError(t, err)
+	require.NotNil(t, rcServer)
+	require.NotNil(t, metricsServer)
+
+	for _, addr := range []string{rcAddr, metricsAddr} {
+		_, err := net.Listen("tcp", addr)
+		require.Error(t, err, "%s should be in use while the servers run", addr)
+	}
+
+	StopRemoteControl()
+	assert.Nil(t, rcServer)
+	assert.Nil(t, metricsServer)
+
+	for _, addr := range []string{rcAddr, metricsAddr} {
+		l, err := net.Listen("tcp", addr)
+		require.NoError(t, err, "%s should be free after StopRemoteControl", addr)
+		require.NoError(t, l.Close())
+	}
+}

cmd/mountlib/mount.go

@@ -309,6 +309,10 @@ func NewMountCommand(commandName string, hidden bool, mount MountFn) *cobra.Comm
 
 			if Opt.Daemon {
 				config.PassConfigKeyForDaemonization = true
+				if !fs.IsDaemon() {
+					// The daemon child starts these servers on the same addresses
+					cmd.StopRemoteControl()
+				}
 			}
 
 			if os.Getenv("PATH") == "" && runtime.GOOS != "windows" {