(dubbo-go) branch develop updated: fix(registry/nacos): add exponential backoff for subscribe retry (#3178)

[alexstocks]

This is an automated email from the ASF dual-hosted git repository.

alexstocks pushed a commit to branch develop
in repository https://gitbox.apache.org/repos/asf/dubbo-go.git


The following commit(s) were added to refs/heads/develop by this push:
     new 842281de1 fix(registry/nacos): add exponential backoff for subscribe 
retry (#3178)
842281de1 is described below

commit 842281de12d56b428d9adb5c6a2e806a72be7d98
Author: CAICAII <3360776...@qq.com>
AuthorDate: Tue Jan 27 16:16:38 2026 +0800

    fix(registry/nacos): add exponential backoff for subscribe retry (#3178)
---
 registry/nacos/registry.go      | 32 +++++++++++++++++++++++++-------
 registry/nacos/registry_test.go | 30 ++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/registry/nacos/registry.go b/registry/nacos/registry.go
index 8c891bcce..b4d59ae17 100644
--- a/registry/nacos/registry.go
+++ b/registry/nacos/registry.go
@@ -19,6 +19,7 @@ package nacos
 
 import (
        "bytes"
+       "context"
        "fmt"
        "math"
        "strconv"
@@ -28,6 +29,8 @@ import (
 )
 
 import (
+       "github.com/cenkalti/backoff/v4"
+
        nacosClient "github.com/dubbogo/gost/database/kv/nacos"
        "github.com/dubbogo/gost/log/logger"
 
@@ -200,15 +203,30 @@ func (nr *nacosRegistry) Subscribe(url *common.URL, 
notifyListener registry.Noti
 }
 
 func (nr *nacosRegistry) subscribeUntilSuccess(url *common.URL, notifyListener 
registry.NotifyListener) {
-       // retry forever
-       for {
+       ctx, cancel := context.WithCancel(context.Background())
+       go func() {
+               <-nr.done
+               cancel()
+       }()
+
+       bo := backoff.NewExponentialBackOff()
+       bo.InitialInterval = 1 * time.Second
+       bo.MaxInterval = 30 * time.Second
+       bo.MaxElapsedTime = 0
+
+       operation := func() error {
                if !nr.IsAvailable() {
-                       return
-               }
-               err := nr.subscribe(getSubscribeName(url), notifyListener)
-               if err == nil {
-                       return
+                       return backoff.Permanent(perrors.New("registry 
unavailable"))
                }
+               return nr.subscribe(getSubscribeName(url), notifyListener)
+       }
+
+       notify := func(err error, duration time.Duration) {
+               logger.Warnf("[Nacos Registry] subscribe failed, retry after 
%v: %v", duration, err)
+       }
+
+       if err := backoff.RetryNotify(operation, backoff.WithContext(bo, ctx), 
notify); err != nil {
+               logger.Infof("[Nacos Registry] subscribe retry stopped: %v", 
err)
        }
 }
 
diff --git a/registry/nacos/registry_test.go b/registry/nacos/registry_test.go
index 9c00c6232..e0b3031c4 100644
--- a/registry/nacos/registry_test.go
+++ b/registry/nacos/registry_test.go
@@ -620,3 +620,33 @@ func TestNacosRegistryCloseListener(t *testing.T) {
                t.Errorf("nl.done channel was not closed")
        }
 }
+
+// TestNacosRegistrySubscribeUntilSuccessWithBackoff tests the exponential 
backoff retry mechanism
+func TestNacosRegistrySubscribeUntilSuccessWithBackoff(t *testing.T) {
+       ctrl := gomock.NewController(t)
+       defer ctrl.Finish()
+
+       mockNamingClient := NewMockINamingClient(ctrl)
+       nc := &nacosClient.NacosNamingClient{}
+       nc.SetClient(mockNamingClient)
+
+       regURL, _ := 
common.NewURL("registry://127.0.0.1:8848?registry.group=testgroup")
+       nr := &nacosRegistry{
+               URL:          regURL,
+               namingClient: nc,
+               done:         make(chan struct{}),
+               registryUrls: []*common.URL{},
+       }
+
+       urlMap := url.Values{}
+       urlMap.Set(constant.RegistryRoleKey, strconv.Itoa(common.CONSUMER))
+       urlMap.Set(constant.InterfaceKey, "com.test.BackoffService")
+       testURL, _ := 
common.NewURL("dubbo://127.0.0.1:20000/com.test.BackoffService", 
common.WithParams(urlMap))
+
+       // Test case: registry becomes unavailable, should stop retrying 
immediately
+       t.Run("stops when registry unavailable", func(t *testing.T) {
+               close(nr.done) // simulate registry shutdown
+               nr.subscribeUntilSuccess(testURL, nil)
+               // If we reach here without hanging, the test passes
+       })
+}