add default value

config/config_resolver.go

@@ -85,15 +85,18 @@ const (
 func resolvePlaceholder(resolver *koanf.Koanf) *koanf.Koanf {
 	m := make(map[string]interface{})
 	for k, v := range resolver.All() {
-		if _, ok := v.(string); !ok {
+		s, ok := v.(string)
+		if !ok {
 			continue
 		}
-		s := v.(string)
-		newKey := checkPlaceholder(s)
+		newKey, defaultValue := checkPlaceholder(s)
 		if newKey == "" {
 			continue
 		}
 		m[k] = resolver.Get(newKey)
+		if m[k] == nil {
+			m[k] = defaultValue
+		}
 	}
 	err := resolver.Load(confmap.Provider(m, resolver.Delim()), nil)
 	if err != nil {
@@ -102,10 +105,19 @@ func resolvePlaceholder(resolver *koanf.Koanf) *koanf.Koanf {
 	return resolver
 }
 
-func checkPlaceholder(s string) string {
-	s = strings.Trim(s, " ")
+func checkPlaceholder(s string) (newKey, defaultValue string) {
+	s = strings.TrimSpace(s)
 	if !strings.HasPrefix(s, PlaceholderPrefix) || !strings.HasSuffix(s, PlaceholderSuffix) {
-		return ""
+		return
+	}
+	s = s[len(PlaceholderPrefix) : len(s)-len(PlaceholderSuffix)]
+	indexColon := strings.Index(s, ":")
+	if indexColon == -1 {
+		newKey = strings.TrimSpace(s)
+		return
 	}
-	return strings.Trim(s[len(PlaceholderPrefix):len(s)-len(PlaceholderSuffix)], " ")
+	newKey = strings.TrimSpace(s[0:indexColon])
+	defaultValue = strings.TrimSpace(s[indexColon+1:])
+
+	return
 }

config/config_resolver_test.go

@@ -1,3 +1,20 @@
+/*
+ * 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 config
 
 import (
@@ -16,14 +33,16 @@ func TestResolvePlaceHolder(t *testing.T) {
 		koan := GetConfigResolver(conf)
 		assert.Equal(t, koan.Get("dubbo.config-center.address"), koan.Get("dubbo.registries.nacos.address"))
 		assert.Equal(t, koan.Get("localhost"), koan.Get("dubbo.protocols.dubbo.ip"))
-		assert.Equal(t, nil, koan.Get("dubbo.registries.nacos.group"))
+		assert.Equal(t, "", koan.Get("dubbo.registries.nacos.group"))
+		assert.Equal(t, "dev", koan.Get("dubbo.registries.zk.group"))
 
 		rc := NewRootConfigBuilder().Build()
 		err := koan.UnmarshalWithConf(rc.Prefix(), rc, koanf.UnmarshalConf{Tag: "yaml"})
 		assert.Nil(t, err)
 		assert.Equal(t, rc.ConfigCenter.Address, rc.Registries["nacos"].Address)
 		//not exist, default
 		assert.Equal(t, "", rc.Registries["nacos"].Group)
+		assert.Equal(t, "dev", rc.Registries["zk"].Group)
 
 	})
 }

config/testdata/config/resolver/application.yaml

@@ -19,10 +19,10 @@ dubbo:
     nacos:
       timeout: 5s
       group: ${notexist}
-      address: ${dubbo.config-center.address}
+      address: ${dubbo.config-center.address:nacos://127.0.0.1:8848}
     zk:
       protocol: zookeeper
-      group: dev
+      group: ${notexist:dev}
       address: 127.0.0.1:2181
   services:
     helloService: