feat(helm): `--update` flag for `helm repo add`

When using `--update` new repositories will be added in the same way as
without  `--update` but if the repository has already been registered
then the endpoint will be updated.

Closes #1141

cmd/helm/repo.go

@@ -31,7 +31,7 @@ import (
 )
 
 func init() {
-	repoCmd.AddCommand(repoAddCmd)
+	repoCmd.AddCommand(repoAddCmd())
 	repoCmd.AddCommand(repoListCmd)
 	repoCmd.AddCommand(repoRemoveCmd)
 	repoCmd.AddCommand(repoIndexCmd)
@@ -43,10 +43,42 @@ var repoCmd = &cobra.Command{
 	Short: "add, list, or remove chart repositories",
 }
 
-var repoAddCmd = &cobra.Command{
+type addCmd struct {
+	update bool
+}
+
+func repoAddCmd() *cobra.Command {
+	add := &addCmd{}
+	cmd := &cobra.Command{
 		Use:   "add [flags] [NAME] [URL]",
 		Short: "add a chart repository",
-	RunE:  runRepoAdd,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if err := checkArgsLength(2, len(args), "name for the chart repository", "the url of the chart repository"); err != nil {
+				return err
+			}
+			name, url := args[0], args[1]
+
+			var err error
+			if add.update {
+				err = updateRepository(name, url)
+			} else {
+				err = addRepository(name, url)
+			}
+			if err != nil {
+				return err
+			}
+
+			if add.update {
+				fmt.Println(name + " has been updated")
+			} else {
+				fmt.Println(name + " has been added to your repositories")
+			}
+			return nil
+		},
+	}
+	f := cmd.Flags()
+	f.BoolVarP(&add.update, "update", "u", false, "update old url if it exists")
+	return cmd
 }
 
 var repoListCmd = &cobra.Command{
@@ -68,20 +100,6 @@ var repoIndexCmd = &cobra.Command{
 	RunE:  runRepoIndex,
 }
 
-func runRepoAdd(cmd *cobra.Command, args []string) error {
-	if err := checkArgsLength(2, len(args), "name for the chart repository", "the url of the chart repository"); err != nil {
-		return err
-	}
-	name, url := args[0], args[1]
-
-	if err := addRepository(name, url); err != nil {
-		return err
-	}
-
-	fmt.Println(name + " has been added to your repositories")
-	return nil
-}
-
 func runRepoList(cmd *cobra.Command, args []string) error {
 	f, err := repo.LoadRepositoriesFile(repositoriesFile())
 	if err != nil {
@@ -141,6 +159,14 @@ func addRepository(name, url string) error {
 	return insertRepoLine(name, url)
 }
 
+func updateRepository(name, url string) error {
+	if err := repo.DownloadIndexFile(name, url, cacheIndexFile(name)); err != nil {
+		return errors.New("Looks like " + url + " is not a valid chart repository or cannot be reached: " + err.Error())
+	}
+
+	return updateRepoLine(name, url)
+}
+
 func removeRepoLine(name string) error {
 	r, err := repo.LoadRepositoriesFile(repositoriesFile())
 	if err != nil {
@@ -197,3 +223,19 @@ func insertRepoLine(name, url string) error {
 	b, _ := yaml.Marshal(&f.Repositories)
 	return ioutil.WriteFile(repositoriesFile(), b, 0666)
 }
+
+func updateRepoLine(name, url string) error {
+	f, err := repo.LoadRepositoriesFile(repositoriesFile())
+	if err != nil {
+		return err
+	}
+
+	if f.Repositories == nil {
+		f.Repositories = make(map[string]string)
+	}
+
+	f.Repositories[name] = url
+
+	b, _ := yaml.Marshal(&f.Repositories)
+	return ioutil.WriteFile(repositoriesFile(), b, 0666)
+}

cmd/helm/repo_test.go

@@ -65,6 +65,10 @@ func TestRepoAdd(t *testing.T) {
 		t.Errorf("Duplicate repository name was added")
 	}
 
+	if err := updateRepository(testName, testURL); err == nil {
+		t.Errorf("Repository was not updated: %s", err)
+	}
+
 }
 
 func TestRepoRemove(t *testing.T) {