only append latest tag to image once, and use regex to check if image has tag

Author: nkubala

cmd/root.go

@@ -135,28 +135,21 @@ func getPrepperForImage(image string) (pkgutil.Prepper, error) {
 	}
 
 	// see if the image name has tag provided, if not add latest as tag
-	if !strings.Contains(image, ":") {
+	if !pkgutil.HasTag(image) {
 		image = image + ":latest"
 	}
 
 	if strings.HasPrefix(image, DaemonPrefix) {
 		// remove the DaemonPrefix
-		image := strings.Replace(image, DaemonPrefix, "", -1)
-		if !strings.Contains(image, ":") {
-			image = image + ":latest"
-		}
+		image = strings.Replace(image, DaemonPrefix, "", -1)
 
 		return pkgutil.DaemonPrepper{
 			Source: image,
 			Client: cli,
 		}, nil
 	}
-	// either has remote prefix or has no prefix, in which case we force remote
 
-	// see if the image name has tag provided, if not add latest as tag
-	if !strings.Contains(image, ":") {
-		image = image + ":latest"
-	}
+	// either has remote prefix or has no prefix, in which case we force remote
 	ref, err := docker.ParseReference("//" + image)
 	if err != nil {
 		return nil, err

pkg/util/image_prep_utils.go

@@ -99,7 +99,14 @@ type ConfigSchema struct {
 }
 
 func getImage(p Prepper) (Image, error) {
-	output.PrintToStdErr("Retrieving image %s from source %s\n", p.GetSource(), p.Name())
+	var source string
+	// see if the image name has tag provided, if not add latest as tag
+	if !HasTag(p.GetSource()) {
+		source = p.GetSource() + ":latest"
+	} else {
+		source = p.GetSource()
+	}
+	output.PrintToStdErr("Retrieving image %s from source %s\n", source, p.Name())
 	imgPath, err := p.GetFileSystem()
 	if err != nil {
 		return Image{}, err
@@ -110,9 +117,9 @@ func getImage(p Prepper) (Image, error) {
 		logrus.Error("Error retrieving History: ", err)
 	}
 
-	logrus.Infof("Finished prepping image %s", p.GetSource())
+	logrus.Infof("Finished prepping image %s", source)
 	return Image{
-		Source: p.GetSource(),
+		Source: source,
 		FSPath: imgPath,
 		Config: config,
 	}, nil

pkg/util/image_utils.go

@@ -21,6 +21,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"regexp"
 
 	"github.com/docker/docker/pkg/system"
 	"github.com/sirupsen/logrus"
@@ -67,3 +68,9 @@ func copyToFile(outfile string, r io.Reader) error {
 
 	return nil
 }
+
+// checks to see if an image string contains a tag.
+func HasTag(image string) bool {
+	tagRegex := regexp.MustCompile(".*:[^/]*$")
+	return tagRegex.MatchString(image)
+}