cmd/list, pkg/podman: Make podman.GetImages() flatten, not getImages()

This is a step towards eliminating or reducing the code in getImages()
by doing everything or more in podman.GetImages().  If nothing else,
this removes the need to export Image.FlattenNames() from the podman
package.

The getImages() function originated as listContainers(), when it invoked
'podman images --filter label=...' through podman.GetImages() separately
for each label used to identify Toolbx images, and then joined and
sorted the results.  This changed in commit 2369da5 when
getImages() started invoking 'podman images' only once through
podman.GetImages() to get all available images, and then filtered them
itself based on the labels.

Before this change in commit 2369da5, it probably made some
sense to keep podman.GetImages() only as a thin wrapper to invoke
'podman images' with different options, and to do everything else in
getImages().  However, since then more is being done inside the podman
package (eg., unmarshalling the 'podman images' JSON in commit
5f324d5 and flattening the images in commit 6aab0a6),
and getImages() is the only caller of podman.GetImages().

Therefore, it looks awkward to have the code to get all Toolbx images
split across two functions in different packages.

containers#1724
containers#1772

Author: DaliborKr

src/cmd/list.go

@@ -154,21 +154,15 @@ func listHelp(cmd *cobra.Command, args []string) {
 func getImages(fillNameWithID bool) ([]podman.Image, error) {
 	logrus.Debug("Fetching all images")
 	var args []string
-	images, err := podman.GetImages(args...)
+	images, err := podman.GetImages(fillNameWithID, args...)
 	if err != nil {
 		logrus.Debugf("Fetching all images failed: %s", err)
 		return nil, errors.New("failed to get images")
 	}
 
-	processed := make(map[string]struct{})
 	var toolboxImages []podman.Image
 
 	for _, image := range images {
-		if _, ok := processed[image.ID]; ok {
-			continue
-		}
-
-		processed[image.ID] = struct{}{}
 		var isToolboxImage bool
 
 		for label := range toolboxLabels {
@@ -179,8 +173,7 @@ func getImages(fillNameWithID bool) ([]podman.Image, error) {
 		}
 
 		if isToolboxImage {
-			flattenedImages := image.FlattenNames(fillNameWithID)
-			toolboxImages = append(toolboxImages, flattenedImages...)
+			toolboxImages = append(toolboxImages, image)
 		}
 
 	}

src/pkg/podman/podman.go

@@ -53,7 +53,7 @@ var (
 	LogLevel = logrus.ErrorLevel
 )
 
-func (image *Image) FlattenNames(fillNameWithID bool) []Image {
+func (image *Image) flattenNames(fillNameWithID bool) []Image {
 	var ret []Image
 
 	if len(image.Names) == 0 {
@@ -190,12 +190,14 @@ func GetContainers(args ...string) (*Containers, error) {
 
 // GetImages is a wrapper function around `podman images --format json` command.
 //
+// Parameter fillNameWithID is a boolean that indicates if the image names should be filled with the ID, when there
+// are no names.
 // Parameter args accepts an array of strings to be passed to the wrapped command (eg. ["-a", "--filter", "123"]).
 //
 // Returned value is a slice of Images.
 //
 // If a problem happens during execution, first argument is nil and second argument holds the error message.
-func GetImages(args ...string) ([]Image, error) {
+func GetImages(fillNameWithID bool, args ...string) ([]Image, error) {
 	var stdout bytes.Buffer
 
 	logLevelString := LogLevel.String()
@@ -210,6 +212,19 @@ func GetImages(args ...string) ([]Image, error) {
 		return nil, err
 	}
 
+	processedIDs := make(map[string]struct{})
+	var processedImages []Image
+
+	for _, image := range images {
+		if _, ok := processedIDs[image.ID]; ok {
+			continue
+		}
+
+		processedIDs[image.ID] = struct{}{}
+		flattenedImages := image.flattenNames(fillNameWithID)
+		processedImages = append(processedImages, flattenedImages...)
+	}
+
 	return images, nil
 }