Implement support for updating stopped containers

This commit adds a command line flag, "--check-all". If true, the
behavior requested by #112 is used (i.e., stopped containers are updated
but not restarted). If false, the previous behavior is used (ignore
stopped containers entirely).

actions/update.go

@@ -67,6 +67,8 @@ func Update(client container.Client, names []string, cleanup bool, noRestart boo
 			continue
 		}
 
+		container.WasRunning = container.IsRunning()
+
 		if container.Stale {
 			if err := client.StopContainer(container, waitTime); err != nil {
 				log.Error(err)

container/client.go

@@ -37,31 +37,41 @@ type Client interface {
 //  * DOCKER_HOST			the docker-engine host to send api requests to
 //  * DOCKER_TLS_VERIFY		whether to verify tls certificates
 //  * DOCKER_API_VERSION	the minimum docker api version to work with
-func NewClient(pullImages, enableLabel bool) Client {
+func NewClient(pullImages, enableLabel bool, checkAll bool) Client {
 	cli, err := dockerclient.NewEnvClient()
 
 	if err != nil {
 		log.Fatalf("Error instantiating Docker client: %s", err)
 	}
 
-	return dockerClient{api: cli, pullImages: pullImages, enableLabel: enableLabel}
+	return dockerClient{
+		api:         cli,
+		pullImages:  pullImages,
+		enableLabel: enableLabel,
+		checkAll:    checkAll}
 }
 
 type dockerClient struct {
 	api         *dockerclient.Client
 	pullImages  bool
 	enableLabel bool
+	checkAll    bool
 }
 
 func (client dockerClient) ListContainers(fn Filter) ([]Container, error) {
 	cs := []Container{}
 	bg := context.Background()
 
-	log.Debug("Retrieving running containers")
+	if client.checkAll {
+		log.Debug("Retrieving containers")
+	} else {
+		log.Debug("Retrieving running containers")
+	}
 
 	runningContainers, err := client.api.ContainerList(
 		bg,
-		types.ContainerListOptions{})
+		types.ContainerListOptions{
+			All: client.checkAll})
 	if err != nil {
 		return nil, err
 	}
@@ -103,10 +113,12 @@ func (client dockerClient) StopContainer(c Container, timeout time.Duration) err
 		signal = defaultStopSignal
 	}
 
-	log.Infof("Stopping %s (%s) with %s", c.Name(), c.ID(), signal)
+	if c.WasRunning {
+		log.Infof("Stopping %s (%s) with %s", c.Name(), c.ID(), signal)
 
-	if err := client.api.ContainerKill(bg, c.ID(), signal); err != nil {
+		if err := client.api.ContainerKill(bg, c.ID(), signal); err != nil {
-		return err
+			return err
+		}
 	}
 
 	// Wait for container to exit, but proceed anyway after the timeout elapses
@@ -173,11 +185,13 @@ func (client dockerClient) StartContainer(c Container) error {
 
 	}
 
-	log.Debugf("Starting container %s (%s)", name, creation.ID)
+	if c.WasRunning {
+		log.Debugf("Starting container %s (%s)", name, creation.ID)
 
-	err = client.api.ContainerStart(bg, creation.ID, types.ContainerStartOptions{})
+		err = client.api.ContainerStart(bg, creation.ID, types.ContainerStartOptions{})
-	if err != nil {
+		if err != nil {
-		return err
+			return err
+		}
 	}
 
 	return nil

container/container.go

@@ -27,7 +27,8 @@ func NewContainer(containerInfo *types.ContainerJSON, imageInfo *types.ImageInsp
 
 // Container represents a running Docker container.
 type Container struct {
-	Stale bool
+	Stale      bool
+	WasRunning bool
 
 	containerInfo *types.ContainerJSON
 	imageInfo     *types.ImageInspect
@@ -106,6 +107,13 @@ func (c Container) IsWatchtower() bool {
 	return ok && val == "true"
 }
 
+// IsRunning returns a boolean flag indicating whether or not the current
+// container is running. The status is determined by the value of the
+// container's "State.Running" property.
+func (c Container) IsRunning() bool {
+	return c.containerInfo.State.Running
+}
+
 // StopSignal returns the custom stop signal (if any) that is encoded in the
 // container's metadata. If the container has not specified a custom stop
 // signal, the empty string "" is returned.

main.go

@@ -61,6 +61,11 @@ func main() {
 			Usage:  "the cron expression which defines when to update",
 			EnvVar: "WATCHTOWER_SCHEDULE",
 		},
+		cli.BoolFlag{
+			Name:   "check-all",
+			Usage:  "check non-running containers",
+			EnvVar: "WATCHTOWER_CHECK_ALL",
+		},
 		cli.BoolFlag{
 			Name:   "no-pull",
 			Usage:  "do not pull new images",
@@ -159,7 +164,7 @@ func before(c *cli.Context) error {
 		return err
 	}
 
-	client = container.NewClient(!c.GlobalBool("no-pull"), c.GlobalBool("label-enable"))
+	client = container.NewClient(!c.GlobalBool("no-pull"), c.GlobalBool("label-enable"), c.GlobalBool("check-all"))
 	notifier = notifications.NewNotifier(c)
 
 	return nil