Add `--stop-signal` for `service create` and `service update`

This fix tries to address the issue raised in 25696 where
it was not possible to specify `--stop-signal` for `docker service create`
and `docker service update`, in order to use special signal to stop
the container.

This fix adds `--stop-signal` and update the `StopSignal` in `Config`
through `service create` and `service update`.

Related docs has been updated.

Integration test has been added.

This fix fixes 25696.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

command/service/opts.go

@@ -269,6 +269,7 @@ type serviceOptions struct {
 	workdir         string
 	user            string
 	groups          opts.ListOpts
+	stopSignal      string
 	tty             bool
 	readOnly        bool
 	mounts          opts.MountOpt
@@ -380,6 +381,7 @@ func (opts *serviceOptions) ToService() (swarm.ServiceSpec, error) {
 				Dir:        opts.workdir,
 				User:       opts.user,
 				Groups:     opts.groups.GetAll(),
+				StopSignal: opts.stopSignal,
 				TTY:        opts.tty,
 				ReadOnly:   opts.readOnly,
 				Mounts:     opts.mounts.Value(),
@@ -470,6 +472,9 @@ func addServiceFlags(cmd *cobra.Command, opts *serviceOptions) {
 
 	flags.BoolVar(&opts.readOnly, flagReadOnly, false, "Mount the container's root filesystem as read only")
 	flags.SetAnnotation(flagReadOnly, "version", []string{"1.27"})
+
+	flags.StringVar(&opts.stopSignal, flagStopSignal, "", "Signal to stop the container")
+	flags.SetAnnotation(flagStopSignal, "version", []string{"1.27"})
 }
 
 const (
@@ -523,6 +528,7 @@ const (
 	flagRestartMaxAttempts    = "restart-max-attempts"
 	flagRestartWindow         = "restart-window"
 	flagStopGracePeriod       = "stop-grace-period"
+	flagStopSignal            = "stop-signal"
 	flagTTY                   = "tty"
 	flagUpdateDelay           = "update-delay"
 	flagUpdateFailureAction   = "update-failure-action"

command/service/update.go

@@ -349,6 +349,8 @@ func updateService(flags *pflag.FlagSet, spec *swarm.ServiceSpec) error {
 		cspec.ReadOnly = readOnly
 	}
 
+	updateString(flagStopSignal, &cspec.StopSignal)
+
 	return nil
 }
 

command/service/update_test.go

@@ -441,3 +441,25 @@ func TestUpdateReadOnly(t *testing.T) {
 	updateService(flags, spec)
 	assert.Equal(t, cspec.ReadOnly, false)
 }
+
+func TestUpdateStopSignal(t *testing.T) {
+	spec := &swarm.ServiceSpec{}
+	cspec := &spec.TaskTemplate.ContainerSpec
+
+	// Update with --stop-signal=SIGUSR1
+	flags := newUpdateCommand(nil).Flags()
+	flags.Set("stop-signal", "SIGUSR1")
+	updateService(flags, spec)
+	assert.Equal(t, cspec.StopSignal, "SIGUSR1")
+
+	// Update without --stop-signal, no change
+	flags = newUpdateCommand(nil).Flags()
+	updateService(flags, spec)
+	assert.Equal(t, cspec.StopSignal, "SIGUSR1")
+
+	// Update with --stop-signal=SIGWINCH
+	flags = newUpdateCommand(nil).Flags()
+	flags.Set("stop-signal", "SIGWINCH")
+	updateService(flags, spec)
+	assert.Equal(t, cspec.StopSignal, "SIGWINCH")
+}