introduce ConfigPostProcessor extension

common/extension/config_post_processor.go

@@ -0,0 +1,45 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package extension
+
+import (
+	"github.com/apache/dubbo-go/config/interfaces"
+)
+
+var (
+	processors = make(map[string]interfaces.ConfigPostProcessor)
+)
+
+// SetConfigPostProcessor registers a ConfigPostProcessor with the given name.
+func SetConfigPostProcessor(name string, processor interfaces.ConfigPostProcessor) {
+	processors[name] = processor
+}
+
+// GetConfigPostProcessor finds a ConfigPostProcessor by name.
+func GetConfigPostProcessor(name string) interfaces.ConfigPostProcessor {
+	return processors[name]
+}
+
+// GetConfigPostProcessors returns all registered instances of ConfigPostProcessor.
+func GetConfigPostProcessors() []interfaces.ConfigPostProcessor {
+	ret := make([]interfaces.ConfigPostProcessor, 0, len(processors))
+	for _, v := range processors {
+		ret = append(ret, v)
+	}
+	return ret
+}

config/interfaces/config_post_processor.go

@@ -0,0 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package interfaces
+
+import (
+	"github.com/apache/dubbo-go/common"
+)
+
+// ConfigPostProcessor is an extension to give users a chance to customize configs against ReferenceConfig and
+// ServiceConfig during deployment time.
+type ConfigPostProcessor interface {
+	// PostProcessReferenceConfig customizes ReferenceConfig's params.
+	PostProcessReferenceConfig(*common.URL)
+
+	// PostProcessServiceConfig customizes ServiceConfig's params.
+	PostProcessServiceConfig(*common.URL)
+}

config/reference_config.go

@@ -100,6 +100,9 @@ func (c *ReferenceConfig) Refer(_ interface{}) {
 	if c.ForceTag {
 		cfgURL.AddParam(constant.ForceUseTag, "true")
 	}
+
+	c.postProcessConfig(cfgURL)
+
 	if c.Url != "" {
 		// 1. user specified URL, could be peer-to-peer address, or register center's address.
 		urlStrings := gxstrings.RegSplit(c.Url, "\\s*[;]+\\s*")
@@ -248,3 +251,10 @@ func (c *ReferenceConfig) GenericLoad(id string) {
 	c.Refer(genericService)
 	c.Implement(genericService)
 }
+
+// postProcessConfig asks registered ConfigPostProcessor to post-process the current ReferenceConfig.
+func (c *ReferenceConfig) postProcessConfig(url *common.URL) {
+	for _, p := range extension.GetConfigPostProcessors() {
+		p.PostProcessReferenceConfig(url)
+	}
+}

config/service_config.go

@@ -198,6 +198,8 @@ func (c *ServiceConfig) Export() error {
 			ivkURL.AddParam(constant.Tagkey, c.Tag)
 		}
 
+		c.postProcessConfig(ivkURL)
+
 		if len(regUrls) > 0 {
 			c.cacheMutex.Lock()
 			if c.cacheProtocol == nil {
@@ -332,3 +334,10 @@ func (c *ServiceConfig) GetExportedUrls() []*common.URL {
 	}
 	return nil
 }
+
+// postProcessConfig asks registered ConfigPostProcessor to post-process the current ServiceConfig.
+func (c *ServiceConfig) postProcessConfig(url *common.URL) {
+	for _, p := range extension.GetConfigPostProcessors() {
+		p.PostProcessServiceConfig(url)
+	}
+}