engine: move default image exclusions

agent/config/config.go

@@ -132,7 +132,6 @@ const (
 	DefaultTaskMetadataBurstRate = 60
 
 	//Known cached image names
-	CachedImageNamePauseContainer = "amazon/amazon-ecs-pause:0.1.0"
 	CachedImageNameAgentContainer = "amazon/amazon-ecs-agent:latest"
 
 	// DefaultNvidiaRuntime is the name of the runtime to pass Nvidia GPUs to containers

agent/config/config_test.go

@@ -419,7 +419,7 @@ func TestValidForImagesCleanupExclusion(t *testing.T) {
 	defer setTestRegion()()
 	defer setTestEnv("ECS_EXCLUDE_UNTRACKED_IMAGE", "amazonlinux:2,amazonlinux:3")()
 	imagesNotDelete := parseImageCleanupExclusionList("ECS_EXCLUDE_UNTRACKED_IMAGE")
-	expectedImages := []string{"amazonlinux:2", "amazonlinux:3", CachedImageNameAgentContainer, CachedImageNamePauseContainer}
+	expectedImages := []string{"amazonlinux:2", "amazonlinux:3"}
 	assert.Equal(t, expectedImages, imagesNotDelete, "unexpected imageCleanupExclusionList")
 }
 

agent/config/parse.go

@@ -309,16 +309,11 @@ func parseImageCleanupExclusionList(envVar string) []string {
 	var imageCleanupExclusionList []string
 	if imageEnv == "" {
 		seelog.Debugf("Environment variable empty: %s", imageEnv)
+		return nil
 	} else {
 		imageCleanupExclusionList = strings.Split(imageEnv, ",")
 	}
 
-	// append known cached internal images to imageCleanupExclusionLis
-	imageCleanupExclusionList = append(imageCleanupExclusionList, CachedImageNameAgentContainer, CachedImageNamePauseContainer)
-
-	for _, image := range imageCleanupExclusionList {
-		seelog.Infof("Image excluded from cleanup: %s", image)
-	}
 	return imageCleanupExclusionList
 }
 

agent/engine/docker_image_manager.go

@@ -81,14 +81,27 @@ func NewImageManager(cfg *config.Config, client dockerapi.DockerClient, state do
 		numImagesToDelete:                  cfg.NumImagesToDeletePerCycle,
 		imageCleanupTimeInterval:           cfg.ImageCleanupInterval,
 		imagePullBehavior:                  cfg.ImagePullBehavior,
-		imageCleanupExclusionList:          cfg.ImageCleanupExclusionList,
+		imageCleanupExclusionList:          buildImageCleanupExclusionList(cfg),
 		deleteNonECSImagesEnabled:          cfg.DeleteNonECSImagesEnabled,
 		nonECSContainerCleanupWaitDuration: cfg.TaskCleanupWaitDuration,
 		numNonECSContainersToDelete:        cfg.NumNonECSContainersToDeletePerCycle,
 		nonECSMinimumAgeBeforeDeletion:     cfg.NonECSMinimumImageDeletionAge,
 	}
 }
 
+func buildImageCleanupExclusionList(cfg *config.Config) []string {
+	// append known cached internal images to imageCleanupExclusionList
+	excludedImages := append(cfg.ImageCleanupExclusionList,
+		cfg.PauseContainerImageName+":"+cfg.PauseContainerTag,
+		config.DefaultPauseContainerImageName+":"+config.DefaultPauseContainerTag,
+		config.CachedImageNameAgentContainer,
+	)
+	for _, image := range excludedImages {
+		seelog.Infof("Image excluded from cleanup: %s", image)
+	}
+	return excludedImages
+}
+
 func (imageManager *dockerImageManager) SetSaver(stateManager statemanager.Saver) {
 	imageManager.saver = stateManager
 }

agent/engine/docker_image_manager_test.go

@@ -44,6 +44,23 @@ func defaultTestConfig() *config.Config {
 	return cfg
 }
 
+func TestNewImageManagerExcludesCachedImages(t *testing.T) {
+	cfg := defaultTestConfig()
+	cfg.PauseContainerImageName = "pause-name"
+	cfg.PauseContainerTag = "pause-tag"
+	cfg.ImageCleanupExclusionList = []string{"excluded:1"}
+	expected := []string{
+		"excluded:1",
+		"pause-name:pause-tag",
+		config.DefaultPauseContainerImageName + ":" + config.DefaultPauseContainerTag,
+		config.CachedImageNameAgentContainer,
+	}
+	imageManager := NewImageManager(cfg, nil, nil)
+	dockerImageManager, ok := imageManager.(*dockerImageManager)
+	require.True(t, ok, "imageManager must be *dockerImageManager")
+	assert.ElementsMatch(t, expected, dockerImageManager.imageCleanupExclusionList)
+}
+
 // TestImagePullRemoveDeadlock tests if there's a deadlock when trying to
 // pull an image while image clean up is in progress
 func TestImagePullRemoveDeadlock(t *testing.T) {