warn and block old repo URLs (#8903)

Signed-off-by: Matt Butcher <matt.butcher@microsoft.com>

cmd/helm/repo_add.go

@@ -37,12 +37,19 @@ import (
 	"helm.sh/helm/v3/pkg/repo"
 )
 
+// Repositories that have been permanently deleted and no longer work
+var deprecatedRepos = map[string]string{
+	"//kubernetes-charts.storage.googleapis.com":           "https://charts.helm.sh/stable",
+	"//kubernetes-charts-incubator.storage.googleapis.com": "https://charts.helm.sh/incubator",
+}
+
 type repoAddOptions struct {
-	name        string
-	url         string
-	username    string
-	password    string
-	forceUpdate bool
+	name                 string
+	url                  string
+	username             string
+	password             string
+	forceUpdate          bool
+	allowDeprecatedRepos bool
 
 	certFile              string
 	keyFile               string
@@ -83,11 +90,21 @@ func newRepoAddCmd(out io.Writer) *cobra.Command {
 	f.StringVar(&o.keyFile, "key-file", "", "identify HTTPS client using this SSL key file")
 	f.StringVar(&o.caFile, "ca-file", "", "verify certificates of HTTPS-enabled servers using this CA bundle")
 	f.BoolVar(&o.insecureSkipTLSverify, "insecure-skip-tls-verify", false, "skip tls certificate checks for the repository")
+	f.BoolVar(&o.allowDeprecatedRepos, "allow-deprecated-repos", false, "by default, this command will not allow adding official repos that have been permanently deleted. This disables that behavior")
 
 	return cmd
 }
 
 func (o *repoAddOptions) run(out io.Writer) error {
+	// Block deprecated repos
+	if !o.allowDeprecatedRepos {
+		for oldURL, newURL := range deprecatedRepos {
+			if strings.Contains(o.url, oldURL) {
+				return fmt.Errorf("repo %q is no longer available; try %q instead", o.url, newURL)
+			}
+		}
+	}
+
 	//Ensure the file directory exists as it is required for file locking
 	err := os.MkdirAll(filepath.Dir(o.repoFile), os.ModePerm)
 	if err != nil && !os.IsExist(err) {

cmd/helm/root.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"os"
 	"strings"
 
 	"github.com/spf13/cobra"
@@ -30,6 +31,7 @@ import (
 
 	"helm.sh/helm/v3/internal/experimental/registry"
 	"helm.sh/helm/v3/pkg/action"
+	"helm.sh/helm/v3/pkg/repo"
 )
 
 var globalUsage = `The Kubernetes package manager
@@ -208,5 +210,54 @@ func newRootCmd(actionConfig *action.Configuration, out io.Writer, args []string
 	// Check permissions on critical files
 	checkPerms()
 
+	// Check for expired repositories
+	checkForExpiredRepos(settings.RepositoryConfig)
+
 	return cmd, nil
 }
+
+func checkForExpiredRepos(repofile string) {
+
+	expiredRepos := []struct {
+		name string
+		old  string
+		new  string
+	}{
+		{
+			name: "stable",
+			old:  "kubernetes-charts.storage.googleapis.com",
+			new:  "https://charts.helm.sh/stable",
+		},
+		{
+			name: "incubator",
+			old:  "kubernetes-charts-incubator.storage.googleapis.com",
+			new:  "https://charts.helm.sh/incubator",
+		},
+	}
+
+	// parse repo file.
+	// Ignore the error because it is okay for a repo file to be unparseable at this
+	// stage. Later checks will trap the error and respond accordingly.
+	repoFile, err := repo.LoadFile(repofile)
+	if err != nil {
+		return
+	}
+
+	for _, exp := range expiredRepos {
+		r := repoFile.Get(exp.name)
+		if r == nil {
+			return
+		}
+
+		if url := r.URL; strings.Contains(url, exp.old) {
+			fmt.Fprintf(
+				os.Stderr,
+				"WARNING: %q is deprecated for %q and will be deleted Nov. 13, 2020.\nWARNING: You should switch to %q\n",
+				exp.old,
+				exp.name,
+				exp.new,
+			)
+		}
+	}
+
+}