root: add --registry-mirror flag

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>

cmd/executor/cmd/root.go

@@ -140,6 +140,7 @@ func addKanikoOptionsFlags(cmd *cobra.Command) {
 	RootCmd.PersistentFlags().DurationVarP(&opts.CacheTTL, "cache-ttl", "", time.Hour*336, "Cache timeout in hours. Defaults to two weeks.")
 	RootCmd.PersistentFlags().VarP(&opts.InsecureRegistries, "insecure-registry", "", "Insecure registry using plain HTTP to push and pull. Set it repeatedly for multiple registries.")
 	RootCmd.PersistentFlags().VarP(&opts.SkipTLSVerifyRegistries, "skip-tls-verify-registry", "", "Insecure registry ignoring TLS verify to push and pull. Set it repeatedly for multiple registries.")
+	RootCmd.PersistentFlags().StringVarP(&opts.RegistryMirror, "registry-mirror", "", "", "Registry mirror to use has pull-through cache instead of docker.io.")
 }
 
 // addHiddenFlags marks certain flags as hidden from the executor help text

pkg/config/options.go

@@ -51,6 +51,7 @@ type KanikoOptions struct {
 	Cleanup                 bool
 	InsecureRegistries      multiArg
 	SkipTLSVerifyRegistries multiArg
+	RegistryMirror          string
 }
 
 // WarmerOptions are options that are set by command line arguments to the cache warmer.

pkg/util/image_util.go

@@ -101,11 +101,25 @@ func remoteImage(image string, opts *config.KanikoOptions) (v1.Image, error) {
 	}
 
 	registryName := ref.Context().RegistryStr()
-	if opts.InsecurePull || opts.InsecureRegistries.Contains(registryName) {
+	var newReg name.Registry
-		newReg, err := name.NewRegistry(registryName, name.WeakValidation, name.Insecure)
+
+	if opts.RegistryMirror != "" && registryName == name.DefaultRegistry {
+		registryName = opts.RegistryMirror
+
+		newReg, err = name.NewRegistry(opts.RegistryMirror, name.StrictValidation)
 		if err != nil {
 			return nil, err
 		}
+	}
+
+	if opts.InsecurePull || opts.InsecureRegistries.Contains(registryName) {
+		newReg, err = name.NewRegistry(registryName, name.WeakValidation, name.Insecure)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if newReg != ref.Context().Registry {
 		if tag, ok := ref.(name.Tag); ok {
 			tag.Repository.Registry = newReg
 			ref = tag