Aias00 commented on code in PR #3441:
URL: https://github.com/apache/dubbo-go/pull/3441#discussion_r3426426537
##########
config_center/nacos/listener.go:
##########
@@ -18,7 +18,6 @@
package nacos
import (
- "context"
"sync"
)
Review Comment:
Thanks for the review! These imports are already present in the file — the
diff only showed the first import block, but the file has three import blocks
(lines 20-22, 24-29, 31-37). The code compiles and all tests pass. No change
needed.
##########
config_center/nacos/listener.go:
##########
@@ -70,17 +68,35 @@ func (n *nacosDynamicConfiguration) addListener(key string,
listener config_cent
return
}
}
- _, cancel := context.WithCancel(context.Background())
listenersMap := rawListenersMap.(*sync.Map)
- listenersMap.Store(listener, cancel)
+ listenersMap.Store(listener, struct{}{})
}
func (n *nacosDynamicConfiguration) removeListener(key string, listener
config_center.ConfigurationListener) {
rawListenersMap, loaded := n.keyListeners.Load(key)
if !loaded {
logger.Errorf("[ConfigCenter][Nacos] key is not be listened,
key=%s", key)
- } else {
- listenersMap := rawListenersMap.(*sync.Map)
- listenersMap.Delete(listener)
+ return
+ }
+ listenersMap := rawListenersMap.(*sync.Map)
+ listenersMap.Delete(listener)
+
+ // If no listeners remain for this key, cancel the nacos config
subscription
+ isEmpty := true
+ listenersMap.Range(func(_, _ any) bool {
+ isEmpty = false
+ return false
+ })
+ if isEmpty {
+ n.keyListeners.Delete(key)
+ if n.client != nil {
+ err :=
n.client.Client().CancelListenConfig(vo.ConfigParam{
+ DataId: key,
+ Group:
n.resolvedGroup(n.url.GetParam(constant.NacosGroupKey,
constant2.DEFAULT_GROUP)),
+ })
+ if err != nil {
+ logger.Errorf("[ConfigCenter][Nacos] cancel
listen config fail, key=%s, err=%v", key, err)
+ }
+ }
}
Review Comment:
Good catch! Fixed in the latest commit. I replaced the bare `sync.Map` with
a `keyListenerSet` struct that uses `sync.Mutex` to make add/remove/check-empty
atomic. This prevents the race where a concurrent `addListener` could add a
listener between the emptiness check and the `CancelListenConfig` call.
Additionally, I now delete from `keyListeners` *before* calling
`CancelListenConfig` so that a new `addListener` won't find the stale set.
##########
config_center/nacos/listener.go:
##########
@@ -70,17 +68,35 @@ func (n *nacosDynamicConfiguration) addListener(key string,
listener config_cent
return
}
}
- _, cancel := context.WithCancel(context.Background())
listenersMap := rawListenersMap.(*sync.Map)
- listenersMap.Store(listener, cancel)
+ listenersMap.Store(listener, struct{}{})
}
func (n *nacosDynamicConfiguration) removeListener(key string, listener
config_center.ConfigurationListener) {
rawListenersMap, loaded := n.keyListeners.Load(key)
if !loaded {
logger.Errorf("[ConfigCenter][Nacos] key is not be listened,
key=%s", key)
- } else {
- listenersMap := rawListenersMap.(*sync.Map)
- listenersMap.Delete(listener)
+ return
+ }
+ listenersMap := rawListenersMap.(*sync.Map)
+ listenersMap.Delete(listener)
+
+ // If no listeners remain for this key, cancel the nacos config
subscription
+ isEmpty := true
+ listenersMap.Range(func(_, _ any) bool {
+ isEmpty = false
+ return false
+ })
+ if isEmpty {
+ n.keyListeners.Delete(key)
+ if n.client != nil {
+ err :=
n.client.Client().CancelListenConfig(vo.ConfigParam{
+ DataId: key,
+ Group:
n.resolvedGroup(n.url.GetParam(constant.NacosGroupKey,
constant2.DEFAULT_GROUP)),
+ })
Review Comment:
Valid concern. Fixed in the latest commit — the resolved `group` string is
now stored in the `keyListenerSet` struct at registration time, and
`CancelListenConfig` uses `set.group` directly instead of re-deriving it. This
guarantees the same (DataId, Group) pair is used for both `ListenConfig` and
`CancelListenConfig`.
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