feat(cmd): Allow to specify which repos to update

This is a port to helm v3 of #5182.
A little more flexible than the v2 version, it allows to specify a list
of repositories that should be updated.

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

cmd/helm/repo_update.go

@@ -32,6 +32,10 @@ import (
 const updateDesc = `
 Update gets the latest information about charts from the respective chart repositories.
 Information is cached locally, where it is used by commands like 'helm search'.
+
+You can optionally specify a list of repositories you want to update.
+	$ helm repo update <repo_name> ...
+To update all the repositories, use 'helm repo update'.
 `
 
 var errNoRepositories = errors.New("no repositories found. You must add one before updating")
@@ -40,21 +44,25 @@ type repoUpdateOptions struct {
 	update    func([]*repo.ChartRepository, io.Writer)
 	repoFile  string
 	repoCache string
+	names     []string
 }
 
 func newRepoUpdateCmd(out io.Writer) *cobra.Command {
 	o := &repoUpdateOptions{update: updateCharts}
 
 	cmd := &cobra.Command{
-		Use:               "update",
-		Aliases:           []string{"up"},
-		Short:             "update information of available charts locally from chart repositories",
-		Long:              updateDesc,
-		Args:              require.NoArgs,
-		ValidArgsFunction: noCompletions,
+		Use:     "update [REPO1 [REPO2 ...]]",
+		Aliases: []string{"up"},
+		Short:   "update information of available charts locally from chart repositories",
+		Long:    updateDesc,
+		Args:    require.MinimumNArgs(0),
+		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			return compListRepos(toComplete, args), cobra.ShellCompDirectiveNoFileComp
+		},
 		RunE: func(cmd *cobra.Command, args []string) error {
 			o.repoFile = settings.RepositoryConfig
 			o.repoCache = settings.RepositoryCache
+			o.names = args
 			return o.run(out)
 		},
 	}
@@ -73,15 +81,26 @@ func (o *repoUpdateOptions) run(out io.Writer) error {
 	}
 
 	var repos []*repo.ChartRepository
-	for _, cfg := range f.Repositories {
-		r, err := repo.NewChartRepository(cfg, getter.All(settings))
-		if err != nil {
+	updateAllRepos := len(o.names) == 0
+
+	if !updateAllRepos {
+		// Fail early if the user specified an invalid repo to update
+		if err := checkRequestedRepos(o.names, f.Repositories); err != nil {
 			return err
 		}
-		if o.repoCache != "" {
-			r.CachePath = o.repoCache
+	}
+
+	for _, cfg := range f.Repositories {
+		if updateAllRepos || isRepoRequested(cfg.Name, o.names) {
+			r, err := repo.NewChartRepository(cfg, getter.All(settings))
+			if err != nil {
+				return err
+			}
+			if o.repoCache != "" {
+				r.CachePath = o.repoCache
+			}
+			repos = append(repos, r)
 		}
-		repos = append(repos, r)
 	}
 
 	o.update(repos, out)
@@ -105,3 +124,28 @@ func updateCharts(repos []*repo.ChartRepository, out io.Writer) {
 	wg.Wait()
 	fmt.Fprintln(out, "Update Complete. ⎈Happy Helming!⎈")
 }
+
+func checkRequestedRepos(requestedRepos []string, validRepos []*repo.Entry) error {
+	for _, requestedRepo := range requestedRepos {
+		found := false
+		for _, repo := range validRepos {
+			if requestedRepo == repo.Name {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return errors.Errorf("no repositories found matching '%s'.  Nothing will be updated", requestedRepo)
+		}
+	}
+	return nil
+}
+
+func isRepoRequested(repoName string, requestedRepos []string) bool {
+	for _, requestedRepo := range requestedRepos {
+		if repoName == requestedRepo {
+			return true
+		}
+	}
+	return false
+}

cmd/helm/repo_update_test.go

@@ -48,8 +48,54 @@ func TestUpdateCmd(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if got := out.String(); !strings.Contains(got, "charts") {
-		t.Errorf("Expected 'charts' got %q", got)
+	if got := out.String(); !strings.Contains(got, "charts") ||
+		!strings.Contains(got, "firstexample") ||
+		!strings.Contains(got, "secondexample") {
+		t.Errorf("Expected 'charts', 'firstexample' and 'secondexample' but got %q", got)
+	}
+}
+
+func TestUpdateCmdMultiple(t *testing.T) {
+	var out bytes.Buffer
+	// Instead of using the HTTP updater, we provide our own for this test.
+	// The TestUpdateCharts test verifies the HTTP behavior independently.
+	updater := func(repos []*repo.ChartRepository, out io.Writer) {
+		for _, re := range repos {
+			fmt.Fprintln(out, re.Config.Name)
+		}
+	}
+	o := &repoUpdateOptions{
+		update:   updater,
+		repoFile: "testdata/repositories.yaml",
+		names:    []string{"firstexample", "charts"},
+	}
+	if err := o.run(&out); err != nil {
+		t.Fatal(err)
+	}
+
+	if got := out.String(); !strings.Contains(got, "charts") ||
+		!strings.Contains(got, "firstexample") ||
+		strings.Contains(got, "secondexample") {
+		t.Errorf("Expected 'charts' and 'firstexample' but not 'secondexample' but got %q", got)
+	}
+}
+
+func TestUpdateCmdInvalid(t *testing.T) {
+	var out bytes.Buffer
+	// Instead of using the HTTP updater, we provide our own for this test.
+	// The TestUpdateCharts test verifies the HTTP behavior independently.
+	updater := func(repos []*repo.ChartRepository, out io.Writer) {
+		for _, re := range repos {
+			fmt.Fprintln(out, re.Config.Name)
+		}
+	}
+	o := &repoUpdateOptions{
+		update:   updater,
+		repoFile: "testdata/repositories.yaml",
+		names:    []string{"firstexample", "invalid"},
+	}
+	if err := o.run(&out); err == nil {
+		t.Fatal("expected error but did not get one")
 	}
 }
 
@@ -111,4 +157,5 @@ func TestUpdateCharts(t *testing.T) {
 
 func TestRepoUpdateFileCompletion(t *testing.T) {
 	checkFileCompletion(t, "repo update", false)
+	checkFileCompletion(t, "repo update repo1", false)
 }

cmd/helm/testdata/repositories.yaml

@@ -2,3 +2,8 @@ apiVersion: v1
 repositories:
   - name: charts
     url: "https://charts.helm.sh/stable"
+  - name: firstexample
+    url: "http://firstexample.com"
+  - name: secondexample
+    url: "http://secondexample.com"
+