Make the external url of cache server configurable if necessary

cmd/input.go

@@ -46,6 +46,7 @@ type Input struct {
 	artifactServerPort                 string
 	noCacheServer                      bool
 	cacheServerPath                    string
+	cacheServerAdvertiseURL            string
 	cacheServerAddr                    string
 	cacheServerPort                    uint16
 	jsonLogger                         bool

cmd/root.go

@@ -94,6 +94,7 @@ func Execute(ctx context.Context, version string) {
 	rootCmd.PersistentFlags().BoolVarP(&input.noSkipCheckout, "no-skip-checkout", "", false, "Do not skip actions/checkout")
 	rootCmd.PersistentFlags().BoolVarP(&input.noCacheServer, "no-cache-server", "", false, "Disable cache server")
 	rootCmd.PersistentFlags().StringVarP(&input.cacheServerPath, "cache-server-path", "", filepath.Join(CacheHomeDir, "actcache"), "Defines the path where the cache server stores caches.")
+	rootCmd.PersistentFlags().StringVarP(&input.cacheServerAdvertiseURL, "cache-server-advertise-url", "", "", "Defines the URL for advertising the cache server behind a proxy. e.g.: https://act-cache-server.example.com")
 	rootCmd.PersistentFlags().StringVarP(&input.cacheServerAddr, "cache-server-addr", "", common.GetOutboundIP().String(), "Defines the address to which the cache server binds.")
 	rootCmd.PersistentFlags().Uint16VarP(&input.cacheServerPort, "cache-server-port", "", 0, "Defines the port where the artifact server listens. 0 means a randomly available port.")
 	rootCmd.PersistentFlags().StringVarP(&input.actionCachePath, "action-cache-path", "", filepath.Join(CacheHomeDir, "act"), "Defines the path where the actions get cached and host workspaces created.")
@@ -598,7 +599,7 @@ func newRunCommand(ctx context.Context, input *Input) func(*cobra.Command, []str
 		var cacheHandler *artifactcache.Handler
 		if !input.noCacheServer && envs[cacheURLKey] == "" {
 			var err error
-			cacheHandler, err = artifactcache.StartHandler(input.cacheServerPath, input.cacheServerAddr, input.cacheServerPort, common.Logger(ctx))
+			cacheHandler, err = artifactcache.StartHandler(input.cacheServerPath, input.cacheServerAdvertiseURL, input.cacheServerAddr, input.cacheServerPort, common.Logger(ctx))
 			if err != nil {
 				return err
 			}

pkg/artifactcache/handler.go

@@ -39,9 +39,10 @@ type Handler struct {
 	gcAt  time.Time
 
 	outboundIP   string
+	advertiseURL string
 }
 
-func StartHandler(dir, outboundIP string, port uint16, logger logrus.FieldLogger) (*Handler, error) {
+func StartHandler(dir, advertiseURL, outboundIP string, port uint16, logger logrus.FieldLogger) (*Handler, error) {
 	h := &Handler{}
 
 	if logger == nil {
@@ -71,6 +72,8 @@ func StartHandler(dir, outboundIP string, port uint16, logger logrus.FieldLogger
 	}
 	h.storage = storage
 
+	h.advertiseURL = advertiseURL
+
 	if outboundIP != "" {
 		h.outboundIP = outboundIP
 	} else if ip := common.GetOutboundIP(); ip == nil {
@@ -111,11 +114,14 @@ func StartHandler(dir, outboundIP string, port uint16, logger logrus.FieldLogger
 }
 
 func (h *Handler) ExternalURL() string {
-	// TODO: make the external url configurable if necessary
+	if h.advertiseURL != "" {
+		return h.advertiseURL
+	} else {
 		return fmt.Sprintf("http://%s:%d",
 			h.outboundIP,
 			h.listener.Addr().(*net.TCPAddr).Port)
 	}
+}
 
 func (h *Handler) Close() error {
 	if h == nil {