Add --no-pull support

container/client.go

@@ -14,14 +14,6 @@ const (
 	signalLabel       = "com.centurylinklabs.watchtower.stop-signal"
 )
 
-var (
-	pullImages bool
-)
-
-func init() {
-	pullImages = true
-}
-
 type Filter func(Container) bool
 
 type Client interface {
@@ -32,18 +24,19 @@ type Client interface {
 	IsContainerStale(Container) (bool, error)
 }
 
-func NewClient(dockerHost string) Client {
+func NewClient(dockerHost string, pullImages bool) Client {
 	docker, err := dockerclient.NewDockerClient(dockerHost, nil)
 
 	if err != nil {
 		log.Fatalf("Error instantiating Docker client: %s\n", err)
 	}
 
-	return DockerClient{api: docker}
+	return DockerClient{api: docker, pullImages: pullImages}
 }
 
 type DockerClient struct {
-	api dockerclient.Client
+	api        dockerclient.Client
+	pullImages bool
 }
 
 func (client DockerClient) ListContainers(fn Filter) ([]Container, error) {
@@ -121,7 +114,7 @@ func (client DockerClient) IsContainerStale(c Container) (bool, error) {
 	oldImageInfo := c.imageInfo
 	imageName := containerInfo.Config.Image
 
-	if pullImages {
+	if client.pullImages {
 		if !strings.Contains(imageName, ":") {
 			imageName = fmt.Sprintf("%s:latest", imageName)
 		}

container/client_test.go

@@ -305,7 +305,7 @@ func TestIsContainerStale_NotStaleSuccess(t *testing.T) {
 	api.On("PullImage", "bar:latest", mock.Anything).Return(nil)
 	api.On("InspectImage", "bar:latest").Return(newImageInfo, nil)
 
-	client := DockerClient{api: api}
+	client := DockerClient{api: api, pullImages: true}
 	stale, err := client.IsContainerStale(c)
 
 	assert.NoError(t, err)
@@ -327,7 +327,28 @@ func TestIsContainerStale_StaleSuccess(t *testing.T) {
 	api.On("PullImage", "bar:1.0", mock.Anything).Return(nil)
 	api.On("InspectImage", "bar:1.0").Return(newImageInfo, nil)
 
-	client := DockerClient{api: api}
+	client := DockerClient{api: api, pullImages: true}
+	stale, err := client.IsContainerStale(c)
+
+	assert.NoError(t, err)
+	assert.True(t, stale)
+	api.AssertExpectations(t)
+}
+
+func TestIsContainerStale_NoPullSuccess(t *testing.T) {
+	c := Container{
+		containerInfo: &dockerclient.ContainerInfo{
+			Name:   "foo",
+			Config: &dockerclient.ContainerConfig{Image: "bar:1.0"},
+		},
+		imageInfo: &dockerclient.ImageInfo{Id: "abc123"},
+	}
+	newImageInfo := &dockerclient.ImageInfo{Id: "xyz789"}
+
+	api := mockclient.NewMockClient()
+	api.On("InspectImage", "bar:1.0").Return(newImageInfo, nil)
+
+	client := DockerClient{api: api, pullImages: false}
 	stale, err := client.IsContainerStale(c)
 
 	assert.NoError(t, err)
@@ -347,7 +368,7 @@ func TestIsContainerStale_PullImageError(t *testing.T) {
 	api := mockclient.NewMockClient()
 	api.On("PullImage", "bar:latest", mock.Anything).Return(errors.New("oops"))
 
-	client := DockerClient{api: api}
+	client := DockerClient{api: api, pullImages: true}
 	_, err := client.IsContainerStale(c)
 
 	assert.Error(t, err)
@@ -369,7 +390,7 @@ func TestIsContainerStale_InspectImageError(t *testing.T) {
 	api.On("PullImage", "bar:latest", mock.Anything).Return(nil)
 	api.On("InspectImage", "bar:latest").Return(newImageInfo, errors.New("uh-oh"))
 
-	client := DockerClient{api: api}
+	client := DockerClient{api: api, pullImages: true}
 	_, err := client.IsContainerStale(c)
 
 	assert.Error(t, err)

main.go

@@ -35,6 +35,10 @@ func main() {
 			Value: 300,
 			Usage: "poll interval (in seconds)",
 		},
+		cli.BoolFlag{
+			Name:  "no-pull",
+			Usage: "do not pull new images",
+		},
 	}
 
 	handleSignals()
@@ -76,5 +80,6 @@ func start(c *cli.Context) {
 
 func newContainerClient(c *cli.Context) container.Client {
 	dockerHost := c.GlobalString("host")
-	return container.NewClient(dockerHost)
+	noPull := c.GlobalBool("no-pull")
+	return container.NewClient(dockerHost, !noPull)
 }