add signal option to container stop command

Signed-off-by: Arjun Raja Yogidas <arjunry@amazon.com>

Author: coderbirju

cmd/nerdctl/container/container_stop.go

@@ -41,6 +41,7 @@ func NewStopCommand() *cobra.Command {
 		SilenceErrors:     true,
 	}
 	stopCommand.Flags().IntP("time", "t", 10, "Seconds to wait before sending a SIGKILL")
+	stopCommand.Flags().StringP("signal", "s", "SIGTERM", "Signal to send to the container")
 	return stopCommand
 }
 
@@ -58,11 +59,20 @@ func processContainerStopOptions(cmd *cobra.Command) (types.ContainerStopOptions
 		t := time.Duration(timeValue) * time.Second
 		timeout = &t
 	}
+	var signal string
+	if cmd.Flags().Changed("signal") {
+		signalValue, err := cmd.Flags().GetString("signal")
+		if err != nil {
+			return types.ContainerStopOptions{}, err
+		}
+		signal = signalValue
+	}
 	return types.ContainerStopOptions{
 		Stdout:   cmd.OutOrStdout(),
 		Stderr:   cmd.ErrOrStderr(),
 		GOptions: globalOptions,
 		Timeout:  timeout,
+		Signal:   signal,
 	}, nil
 }
 

pkg/api/types/container_types.go

@@ -275,6 +275,9 @@ type ContainerStopOptions struct {
 	// Timeout specifies how long to wait after sending a SIGTERM and before sending a SIGKILL.
 	// If it's nil, the default is 10 seconds.
 	Timeout *time.Duration
+
+	// singal to send to the container, before sending sigkill
+	Signal string
 }
 
 // ContainerRestartOptions specifies options for `nerdctl (container) restart`.

pkg/cmd/container/restart.go

@@ -35,7 +35,7 @@ func Restart(ctx context.Context, client *containerd.Client, containers []string
 			if found.MatchCount > 1 {
 				return fmt.Errorf("multiple IDs found with provided prefix: %s", found.Req)
 			}
-			if err := containerutil.Stop(ctx, found.Container, options.Timeout); err != nil {
+			if err := containerutil.Stop(ctx, found.Container, options.Timeout, "SIGTERM"); err != nil {
 				return err
 			}
 			if err := containerutil.Start(ctx, found.Container, false, client, ""); err != nil {

pkg/cmd/container/stop.go

@@ -39,7 +39,7 @@ func Stop(ctx context.Context, client *containerd.Client, reqs []string, opt typ
 			if err := cleanupNetwork(ctx, found.Container, opt.GOptions); err != nil {
 				return fmt.Errorf("unable to cleanup network for container: %s", found.Req)
 			}
-			if err := containerutil.Stop(ctx, found.Container, opt.Timeout); err != nil {
+			if err := containerutil.Stop(ctx, found.Container, opt.Timeout, opt.Signal); err != nil {
 				if errdefs.IsNotFound(err) {
 					fmt.Fprintf(opt.Stderr, "No such container: %s\n", found.Req)
 					return nil

pkg/containerutil/containerutil.go

@@ -26,6 +26,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"syscall"
 	"time"
 
 	dockercliopts "github.com/docker/cli/opts"
@@ -336,7 +337,7 @@ func Start(ctx context.Context, container containerd.Container, flagA bool, clie
 }
 
 // Stop stops `container` by sending SIGTERM. If the container is not stopped after `timeout`, it sends a SIGKILL.
-func Stop(ctx context.Context, container containerd.Container, timeout *time.Duration) (err error) {
+func Stop(ctx context.Context, container containerd.Container, timeout *time.Duration, signalValue string) (err error) {
 	// defer the storage of stop error in the dedicated label
 	defer func() {
 		if err != nil {
@@ -409,16 +410,10 @@ func Stop(ctx context.Context, container containerd.Container, timeout *time.Dur
 	}
 
 	if *timeout > 0 {
-		sig, err := signal.ParseSignal("SIGTERM")
+		sig, err := getSignal(signalValue, l)
 		if err != nil {
 			return err
 		}
-		if stopSignal, ok := l[containerd.StopSignalLabel]; ok {
-			sig, err = signal.ParseSignal(stopSignal)
-			if err != nil {
-				return err
-			}
-		}
 
 		if err := task.Kill(ctx, sig); err != nil {
 			return err
@@ -465,6 +460,18 @@ func Stop(ctx context.Context, container containerd.Container, timeout *time.Dur
 	return waitContainerStop(ctx, exitCh, container.ID())
 }
 
+func getSignal(signalValue string, containerLabels map[string]string) (syscall.Signal, error) {
+	if signalValue != "" {
+		return signal.ParseSignal(signalValue)
+	}
+
+	if stopSignal, ok := containerLabels[containerd.StopSignalLabel]; ok {
+		return signal.ParseSignal(stopSignal)
+	}
+
+	return signal.ParseSignal("SIGTERM")
+}
+
 func waitContainerStop(ctx context.Context, exitCh <-chan containerd.ExitStatus, id string) error {
 	select {
 	case <-ctx.Done():