feat(helm): update repo by default, added `--no-update` flag

cmd/helm/repo_add.go

@@ -28,10 +28,11 @@ import (
 )
 
 type repoAddCmd struct {
-	name string
-	url  string
-	home helmpath.Home
-	out  io.Writer
+	name     string
+	url      string
+	home     helmpath.Home
+	out      io.Writer
+	noupdate bool
 }
 
 func newRepoAddCmd(out io.Writer) *cobra.Command {
@@ -54,11 +55,19 @@ func newRepoAddCmd(out io.Writer) *cobra.Command {
 			return add.run()
 		},
 	}
+	f := cmd.Flags()
+	f.BoolVar(&add.noupdate, "no-update", false, "raise error if repo is already registered")
 	return cmd
 }
 
 func (a *repoAddCmd) run() error {
-	if err := addRepository(a.name, a.url, a.home); err != nil {
+	var err error
+	if a.noupdate {
+		err = addRepository(a.name, a.url, a.home)
+	} else {
+		err = updateRepository(a.name, a.url, a.home)
+	}
+	if err != nil {
 		return err
 	}
 	fmt.Fprintf(a.out, "%q has been added to your repositories\n", a.name)
@@ -91,3 +100,28 @@ func insertRepoLine(name, url string, home helmpath.Home) error {
 	})
 	return f.WriteFile(home.RepositoryFile(), 0644)
 }
+
+func updateRepository(name, url string, home helmpath.Home) error {
+	cif := home.CacheIndex(name)
+	if err := repo.DownloadIndexFile(name, url, cif); err != nil {
+		return err
+	}
+
+	return updateRepoLine(name, url, home)
+}
+
+func updateRepoLine(name, url string, home helmpath.Home) error {
+	cif := home.CacheIndex(name)
+	f, err := repo.LoadRepositoriesFile(home.RepositoryFile())
+	if err != nil {
+		return err
+	}
+
+	f.Update(&repo.Entry{
+		Name:  name,
+		URL:   url,
+		Cache: filepath.Base(cif),
+	})
+
+	return f.WriteFile(home.RepositoryFile(), 0666)
+}

cmd/helm/repo_add_test.go

@@ -92,4 +92,12 @@ func TestRepoAdd(t *testing.T) {
 	if !f.Has(testName) {
 		t.Errorf("%s was not successfully inserted into %s", testName, hh.RepositoryFile())
 	}
+
+	if err := updateRepository(testName, ts.URL(), hh); err != nil {
+		t.Errorf("Repository was not updated: %s", err)
+	}
+
+	if err := addRepository(testName, ts.URL(), hh); err == nil {
+		t.Errorf("Duplicate repository name was added")
+	}
 }

pkg/repo/repo.go

@@ -109,6 +109,20 @@ func (r *RepoFile) Add(re ...*Entry) {
 	r.Repositories = append(r.Repositories, re...)
 }
 
+// Update attempts to replace one or more repo entries in a repo file. If an
+// entry with the same name doesn't exist in the repo file it will add it.
+func (r *RepoFile) Update(re ...*Entry) {
+	for _, target := range re {
+		for j, repo := range r.Repositories {
+			if repo.Name == target.Name {
+				r.Repositories[j] = target
+				break
+			}
+		}
+		r.Add(target)
+	}
+}
+
 // Has returns true if the given name is already a repository name.
 func (r *RepoFile) Has(name string) bool {
 	for _, rf := range r.Repositories {