Add label definitions that allow containers to override image name and id

pkg/container/client.go

@@ -332,6 +332,12 @@ func (client dockerClient) HasNewImage(ctx context.Context, container t.Containe
 	currentImageID := t.ImageID(container.ContainerInfo().ContainerJSONBase.Image)
 	imageName := container.ImageName()
 
+	imageIDSetByLabel, ok := container.ContainerInfo().Config.Labels[originalImageIDLabel]
+	if ok {
+		currentImageID = t.ImageID(imageIDSetByLabel)
+		log.Infof("Original image id for %s found: (%s)", imageName, currentImageID.ShortID())
+	}
+
 	newImageInfo, _, err := client.api.ImageInspectWithRaw(ctx, imageName)
 	if err != nil {
 		return false, currentImageID, err

pkg/container/container.go

@@ -103,7 +103,7 @@ func (c Container) SafeImageID() wt.ImageID {
 // "latest" tag is assumed.
 func (c Container) ImageName() string {
 	// Compatibility w/ Zodiac deployments
-	imageName, ok := c.getLabelValue(zodiacLabel)
+	imageName, ok := c.getLabelValue(originalImageNameLabel)
 	if !ok {
 		imageName = c.containerInfo.Config.Image
 	}

pkg/container/metadata.go

@@ -10,6 +10,8 @@ const (
 	noPullLabel            = "com.centurylinklabs.watchtower.no-pull"
 	dependsOnLabel         = "com.centurylinklabs.watchtower.depends-on"
 	zodiacLabel            = "com.centurylinklabs.zodiac.original-image"
+	originalImageNameLabel = "com.centurylinklabs.watchtower.original-image"
+	originalImageIDLabel   = "com.centurylinklabs.watchtower.original-image-id"
 	scope                  = "com.centurylinklabs.watchtower.scope"
 	preCheckLabel          = "com.centurylinklabs.watchtower.lifecycle.pre-check"
 	postCheckLabel         = "com.centurylinklabs.watchtower.lifecycle.post-check"