fix(concurrency): add mutex to protect repoFailList and out in updateCharts

Signed-off-by: Suleiman Dibirov <idsulik@gmail.com>

pkg/cmd/repo_update.go

@@ -111,20 +111,30 @@ func (o *repoUpdateOptions) run(out io.Writer) error {
 func updateCharts(repos []*repo.ChartRepository, out io.Writer) error {
 	fmt.Fprintln(out, "Hang tight while we grab the latest from your chart repositories...")
 	var wg sync.WaitGroup
-	var repoFailList []string
+	failRepoURLChan := make(chan string, len(repos))
+
 	for _, re := range repos {
 		wg.Add(1)
 		go func(re *repo.ChartRepository) {
 			defer wg.Done()
 			if _, err := re.DownloadIndexFile(); err != nil {
 				fmt.Fprintf(out, "...Unable to get an update from the %q chart repository (%s):\n\t%s\n", re.Config.Name, re.Config.URL, err)
-				repoFailList = append(repoFailList, re.Config.URL)
+				failRepoURLChan <- re.Config.URL
 			} else {
 				fmt.Fprintf(out, "...Successfully got an update from the %q chart repository\n", re.Config.Name)
 			}
 		}(re)
 	}
-	wg.Wait()
+
+	go func() {
+		wg.Wait()
+		close(failRepoURLChan)
+	}()
+
+	var repoFailList []string
+	for url := range failRepoURLChan {
+		repoFailList = append(repoFailList, url)
+	}
 
 	if len(repoFailList) > 0 {
 		return fmt.Errorf("Failed to update the following repositories: %s",

pkg/cmd/repo_update_test.go

@@ -172,7 +172,14 @@ func TestUpdateChartsFailWithError(t *testing.T) {
 	defer ts.Stop()
 
 	var invalidURL = ts.URL() + "55"
-	r, err := repo.NewChartRepository(&repo.Entry{
+	r1, err := repo.NewChartRepository(&repo.Entry{
+		Name: "charts",
+		URL:  invalidURL,
+	}, getter.All(settings))
+	if err != nil {
+		t.Error(err)
+	}
+	r2, err := repo.NewChartRepository(&repo.Entry{
 		Name: "charts",
 		URL:  invalidURL,
 	}, getter.All(settings))
@@ -181,7 +188,7 @@ func TestUpdateChartsFailWithError(t *testing.T) {
 	}
 
 	b := bytes.NewBuffer(nil)
-	err = updateCharts([]*repo.ChartRepository{r}, b)
+	err = updateCharts([]*repo.ChartRepository{r1, r2}, b)
 	if err == nil {
 		t.Error("Repo update should return error because update of repository fails and 'fail-on-repo-update-fail' flag set")
 		return