fix(extension): guard directory/customizer/shutdown/name mapping state

Fixes: #3247

Author: xxs588

common/extension/graceful_shutdown.go

@@ -19,9 +19,11 @@ package extension
 
 import (
 	"container/list"
+	"sync"
 )
 
 var customShutdownCallbacks = list.New()
+var customShutdownCallbacksLock sync.Mutex
 
 /**
  * AddCustomShutdownCallback
@@ -44,10 +46,20 @@ var customShutdownCallbacks = list.New()
  * And it may introduce much complication for another users.
  */
 func AddCustomShutdownCallback(callback func()) {
+	customShutdownCallbacksLock.Lock()
+	defer customShutdownCallbacksLock.Unlock()
+
 	customShutdownCallbacks.PushBack(callback)
 }
 
 // GetAllCustomShutdownCallbacks gets all custom shutdown callbacks
 func GetAllCustomShutdownCallbacks() *list.List {
-	return customShutdownCallbacks
+	customShutdownCallbacksLock.Lock()
+	defer customShutdownCallbacksLock.Unlock()
+
+	ret := list.New()
+	for e := customShutdownCallbacks.Front(); e != nil; e = e.Next() {
+		ret.PushBack(e.Value)
+	}
+	return ret
 }

common/extension/registry_directory.go

@@ -22,32 +22,35 @@ import (
 )
 
 import (
+	"sync/atomic"
+
 	"dubbo.apache.org/dubbo-go/v3/cluster/directory"
 	"dubbo.apache.org/dubbo-go/v3/common"
 	"dubbo.apache.org/dubbo-go/v3/registry"
 )
 
 type registryDirectory func(url *common.URL, registry registry.Registry) (directory.Directory, error)
 
-var directories = make(map[string]registryDirectory)
-var defaultDirectory registryDirectory
+var directories = NewRegistry[registryDirectory]("registry directory")
+var defaultDirectory atomic.Value
 
 // SetDefaultRegistryDirectory sets the default registryDirectory
 func SetDefaultRegistryDirectory(v registryDirectory) {
-	defaultDirectory = v
+	defaultDirectory.Store(v)
 }
 
 // SetDirectory sets the default registryDirectory
 func SetDirectory(key string, v registryDirectory) {
-	directories[key] = v
+	directories.Register(key, v)
 }
 
 // GetDefaultRegistryDirectory finds the registryDirectory with url and registry
 func GetDefaultRegistryDirectory(url *common.URL, registry registry.Registry) (directory.Directory, error) {
-	if defaultDirectory == nil {
+	v := defaultDirectory.Load()
+	if v == nil {
 		panic("registry directory is not existing, make sure you have import the package.")
 	}
-	return defaultDirectory(url, registry)
+	return v.(registryDirectory)(url, registry)
 }
 
 // GetDirectoryInstance finds the registryDirectory with url and registry
@@ -56,9 +59,10 @@ func GetDirectoryInstance(url *common.URL, registry registry.Registry) (director
 	if key == "" {
 		return GetDefaultRegistryDirectory(url, registry)
 	}
-	if directories[key] == nil {
+	v, ok := directories.Get(key)
+	if !ok {
 		logger.Warn("registry directory " + key + " does not exist, make sure you have import the package, will use the default directory type.")
 		return GetDefaultRegistryDirectory(url, registry)
 	}
-	return directories[key](url, registry)
+	return v(url, registry)
 }

common/extension/service_instance_customizer.go

@@ -19,25 +19,35 @@ package extension
 
 import (
 	"sort"
+	"sync"
 )
 
 import (
 	"dubbo.apache.org/dubbo-go/v3/registry"
 )
 
 var customizers = make([]registry.ServiceInstanceCustomizer, 0, 8)
+var customizersLock sync.RWMutex
 
 // AddCustomizers will put the customizer into slices and then sort them;
 // this method will be invoked several time, so we sort them here.
 func AddCustomizers(cus registry.ServiceInstanceCustomizer) {
+	customizersLock.Lock()
+	defer customizersLock.Unlock()
+
 	customizers = append(customizers, cus)
 	sort.Stable(customizerSlice(customizers))
 }
 
 // GetCustomizers will return the sorted customizer
 // the result won't be nil
 func GetCustomizers() []registry.ServiceInstanceCustomizer {
-	return customizers
+	customizersLock.RLock()
+	defer customizersLock.RUnlock()
+
+	ret := make([]registry.ServiceInstanceCustomizer, len(customizers))
+	copy(ret, customizers)
+	return ret
 }
 
 type customizerSlice []registry.ServiceInstanceCustomizer

common/extension/service_name_mapping.go

@@ -18,17 +18,23 @@
 package extension
 
 import (
+	"sync/atomic"
+
 	"dubbo.apache.org/dubbo-go/v3/metadata/mapping"
 )
 
 type ServiceNameMappingCreator func() mapping.ServiceNameMapping
 
-var globalNameMappingCreator ServiceNameMappingCreator
+var globalNameMappingCreator atomic.Value
 
 func SetGlobalServiceNameMapping(nameMappingCreator ServiceNameMappingCreator) {
-	globalNameMappingCreator = nameMappingCreator
+	globalNameMappingCreator.Store(nameMappingCreator)
 }
 
 func GetGlobalServiceNameMapping() mapping.ServiceNameMapping {
-	return globalNameMappingCreator()
+	v := globalNameMappingCreator.Load()
+	if v == nil {
+		panic("global service name mapping creator is not existing")
+	}
+	return v.(ServiceNameMappingCreator)()
 }