fixes #2689 Make the external url of cache server configurable if necessary (#2690)

* Make the external url of cache server configurable if necessary

Signed-off-by: Zoupers <qy@zouper.cn>

* optimize code and doc and fix test and add test

Signed-off-by: Zoupers <qy@zouper.cn>

* optimize code and adjust description

Signed-off-by: Zoupers <qy@zouper.cn>

---------

Signed-off-by: Zoupers <qy@zouper.cn>
Co-authored-by: 林玮 (Jade Lin) <linw1995@icloud.com>

pkg/artifactcache/handler.go

@@ -38,10 +38,11 @@ type Handler struct {
 	gcing atomic.Bool
 	gcAt  time.Time
 
-	outboundIP string
+	outboundIP        string
+	customExternalURL string
 }
 
-func StartHandler(dir, outboundIP string, port uint16, logger logrus.FieldLogger) (*Handler, error) {
+func StartHandler(dir, customExternalURL string, outboundIP string, port uint16, logger logrus.FieldLogger) (*Handler, error) {
 	h := &Handler{}
 
 	if logger == nil {
@@ -71,6 +72,10 @@ func StartHandler(dir, outboundIP string, port uint16, logger logrus.FieldLogger
 	}
 	h.storage = storage
 
+	if customExternalURL != "" {
+		h.customExternalURL = customExternalURL
+	}
+
 	if outboundIP != "" {
 		h.outboundIP = outboundIP
 	} else if ip := common.GetOutboundIP(); ip == nil {
@@ -95,6 +100,7 @@ func StartHandler(dir, outboundIP string, port uint16, logger logrus.FieldLogger
 	if err != nil {
 		return nil, err
 	}
+
 	server := &http.Server{
 		ReadHeaderTimeout: 2 * time.Second,
 		Handler:           router,
@@ -110,11 +116,15 @@ func StartHandler(dir, outboundIP string, port uint16, logger logrus.FieldLogger
 	return h, nil
 }
 
+func (h *Handler) GetActualPort() int {
+	return h.listener.Addr().(*net.TCPAddr).Port
+}
+
 func (h *Handler) ExternalURL() string {
-	// TODO: make the external url configurable if necessary
-	return fmt.Sprintf("http://%s:%d",
-		h.outboundIP,
-		h.listener.Addr().(*net.TCPAddr).Port)
+	if h.customExternalURL != "" {
+		return h.customExternalURL
+	}
+	return fmt.Sprintf("http://%s:%d", h.outboundIP, h.GetActualPort())
 }
 
 func (h *Handler) Close() error {

pkg/artifactcache/handler_test.go

@@ -20,7 +20,7 @@ import (
 
 func TestHandler(t *testing.T) {
 	dir := filepath.Join(t.TempDir(), "artifactcache")
-	handler, err := StartHandler(dir, "", 0, nil)
+	handler, err := StartHandler(dir, "", "", 0, nil)
 	require.NoError(t, err)
 
 	base := fmt.Sprintf("%s%s", handler.ExternalURL(), urlBase)
@@ -587,9 +587,43 @@ func uploadCacheNormally(t *testing.T, base, key, version string, content []byte
 	}
 }
 
+func TestHandler_CustomExternalURL(t *testing.T) {
+	dir := filepath.Join(t.TempDir(), "artifactcache")
+	handler, err := StartHandler(dir, "", "", 0, nil)
+	require.NoError(t, err)
+
+	defer func() {
+		require.NoError(t, handler.Close())
+	}()
+
+	handler.customExternalURL = fmt.Sprintf("http://%s:%d", "127.0.0.1", handler.GetActualPort())
+
+	assert.Equal(t, fmt.Sprintf("http://%s:%d", "127.0.0.1", handler.GetActualPort()), handler.ExternalURL())
+
+	base := fmt.Sprintf("%s%s", handler.ExternalURL(), urlBase)
+
+	t.Run("advertise url set wrong", func(t *testing.T) {
+		original := handler.customExternalURL
+		defer func() {
+			handler.customExternalURL = original
+		}()
+		handler.customExternalURL = "http://127.0.0.999:1234"
+		assert.Equal(t, "http://127.0.0.999:1234", handler.ExternalURL())
+	})
+
+	t.Run("reserve and upload", func(t *testing.T) {
+		key := strings.ToLower(t.Name())
+		version := "c19da02a2bd7e77277f1ac29ab45c09b7d46a4ee758284e26bb3045ad11d9d20"
+		content := make([]byte, 100)
+		_, err := rand.Read(content)
+		require.NoError(t, err)
+		uploadCacheNormally(t, base, key, version, content)
+	})
+}
+
 func TestHandler_gcCache(t *testing.T) {
 	dir := filepath.Join(t.TempDir(), "artifactcache")
-	handler, err := StartHandler(dir, "", 0, nil)
+	handler, err := StartHandler(dir, "", "", 0, nil)
 	require.NoError(t, err)
 
 	defer func() {