Merge pull request #139 from mnottale/extract-use-image

Extract: Also look for a docker image.

Author: mnottale

cmd/load.go

@@ -11,7 +11,7 @@ var loadCmd = &cobra.Command{
 	Short: "Load an application from a docker image",
 	Args:  cli.RequiresMaxArgs(1),
 	RunE: func(cmd *cobra.Command, args []string) error {
-		return packager.Load(firstOrEmpty(args))
+		return packager.Load(firstOrEmpty(args), ".")
 	},
 }
 

packager/extract.go

@@ -46,9 +46,35 @@ func findApp() (string, error) {
 	return filepath.Join(cwd, hit), nil
 }
 
+// extractImage extracts a docker application in a docker image to a temporary directory
+func extractImage(appname string) (string, func(), error) {
+	var imagename string
+	if strings.Contains(appname, ":") {
+		nametag := strings.SplitN(appname, ":", 2)
+		nametag[0] = utils.DirNameFromAppName(nametag[0])
+		appname = filepath.Base(nametag[0])
+		imagename = strings.Join(nametag, ":")
+	} else {
+		imagename = utils.DirNameFromAppName(appname)
+		appname = filepath.Base(imagename)
+	}
+	tempDir, err := ioutil.TempDir("", "dockerapp")
+	if err != nil {
+		return "", noop, err
+	}
+	defer os.RemoveAll(tempDir)
+	err = Load(imagename, tempDir)
+	if err != nil {
+		return "", noop, fmt.Errorf("could not locate application in either filesystem or docker image")
+	}
+	// this gave us a compressed app, run through extract again
+	return Extract(filepath.Join(tempDir, appname))
+}
+
 // Extract extracts the app content if argument is an archive, or does nothing if a dir.
 // It returns effective app name, and cleanup function
 // If appname is empty, it looks into cwd, and all subdirs for a single matching .dockerapp
+// If nothing is found, it looks for an image and loads it
 func Extract(appname string) (string, func(), error) {
 	if appname == "" {
 		var err error
@@ -62,6 +88,7 @@ func Extract(appname string) (string, func(), error) {
 			return "", nil, errors.Wrap(err, "cannot resolve current working directory")
 		}
 	}
+	originalAppname := appname
 	// try verbatim first
 	s, err := os.Stat(appname)
 	if err != nil {
@@ -70,7 +97,8 @@ func Extract(appname string) (string, func(), error) {
 		s, err = os.Stat(appname)
 	}
 	if err != nil {
-		return "", noop, err
+		// look for a docker image
+		return extractImage(originalAppname)
 	}
 	if s.IsDir() {
 		// directory: already decompressed

packager/registry.go

@@ -47,7 +47,7 @@ COPY / /
 }
 
 // Load loads an app from docker
-func Load(repotag string) error {
+func Load(repotag string, outputDir string) error {
 	file := filepath.Join(os.TempDir(), "docker-app-"+fmt.Sprintf("%v%v", rand.Int63(), rand.Int63()))
 	cmd := exec.Command("docker", "save", "-o", file, repotag)
 	output, err := cmd.CombinedOutput()
@@ -75,7 +75,7 @@ func Load(repotag string) error {
 				return errors.Wrap(err, "error reading tar data")
 			}
 			repo := strings.Split(repotag, ":")[0]
-			err = ioutil.WriteFile(appName(repo)+constants.AppExtension, data, 0644)
+			err = ioutil.WriteFile(filepath.Join(outputDir, utils.DirNameFromAppName(filepath.Base(repo))), data, 0644)
 			return errors.Wrap(err, "error writing output file")
 		}
 	}
@@ -108,5 +108,5 @@ func Pull(repotag string) error {
 	if err != nil {
 		return errors.Wrapf(err, "error from docker pull command: %s", string(output))
 	}
-	return Load(repotag)
+	return Load(repotag, ".")
 }

utils/names.go

@@ -20,7 +20,10 @@ func AppNameFromDir(dirName string) string {
 // DirNameFromAppName takes an application name and returns the
 // corresponding directory name
 func DirNameFromAppName(appName string) string {
-	return fmt.Sprintf("%s%s", appName, constants.AppExtension)
+	if strings.HasSuffix(appName, constants.AppExtension) {
+		return appName
+	}
+	return appName + constants.AppExtension
 }
 
 // ValidateAppName takes an app name and returns an error if it doesn't