[GitHub] [dubbo-go] fangyincheng commented on a change in pull request #604: Ftr: Application-level Registry Model

[GitBox <gi...@apache.org>]

fangyincheng commented on a change in pull request #604:
URL: https://github.com/apache/dubbo-go/pull/604#discussion_r447877267



##########
File path: registry/etcdv3/service_discovery.go
##########
@@ -0,0 +1,322 @@
+/*
+ * 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 etcdv3
+
+import (
+	"fmt"
+	"sync"
+	"time"
+)
+
+import (
+	gxset "github.com/dubbogo/gost/container/set"
+	gxpage "github.com/dubbogo/gost/page"
+	"github.com/hashicorp/vault/helper/jsonutil"
+	perrors "github.com/pkg/errors"
+)
+
+import (
+	"github.com/apache/dubbo-go/common/constant"
+	"github.com/apache/dubbo-go/common/extension"
+	"github.com/apache/dubbo-go/common/logger"
+	"github.com/apache/dubbo-go/config"
+	"github.com/apache/dubbo-go/registry"
+	"github.com/apache/dubbo-go/remoting"
+	"github.com/apache/dubbo-go/remoting/etcdv3"
+)
+
+const (
+	ROOT = "/services"
+)
+
+var (
+	initLock sync.Mutex
+)
+
+func init() {
+	extension.SetServiceDiscovery(constant.ETCDV3_KEY, newEtcdV3ServiceDiscovery)
+}
+
+// new etcd service discovery struct
+type etcdV3ServiceDiscovery struct {
+	// descriptor is a short string about the basic information of this instance
+	descriptor string
+	// client is current Etcdv3 client
+	client *etcdv3.Client
+	// serviceInstance is current serviceInstance
+	serviceInstance *registry.ServiceInstance
+	// services is when register or update will add service name
+	services *gxset.HashSet
+	// child listener
+	childListenerMap map[string]*etcdv3.EventListener
+}
+
+// basic information of this instance
+func (e *etcdV3ServiceDiscovery) String() string {
+	return e.descriptor
+}
+
+// Destory service discovery
+func (e *etcdV3ServiceDiscovery) Destroy() error {
+	if e.client != nil {
+		e.client.Close()
+	}
+	return nil
+}
+
+// Register will register an instance of ServiceInstance to registry
+func (e *etcdV3ServiceDiscovery) Register(instance registry.ServiceInstance) error {
+
+	e.serviceInstance = &instance
+
+	path := toPath(instance)
+
+	if nil != e.client {
+		ins, err := jsonutil.EncodeJSON(instance)
+		if err == nil {
+			err = e.client.RegisterTemp(path, string(ins))
+			if err != nil {
+				logger.Errorf("cannot register the instance: %s", string(ins), err)
+			} else {
+				e.services.Add(instance.GetServiceName())
+			}
+		}
+	}
+
+	return nil
+}
+
+// Update will update the data of the instance in registry
+func (e *etcdV3ServiceDiscovery) Update(instance registry.ServiceInstance) error {
+	path := toPath(instance)
+
+	if nil != e.client {
+		ins, err := jsonutil.EncodeJSON(instance)
+		if nil == err {
+			e.client.RegisterTemp(path, string(ins))
+			e.services.Add(instance.GetServiceName())
+		}
+	}
+
+	return nil
+}
+
+// Unregister will unregister this instance from registry
+func (e *etcdV3ServiceDiscovery) Unregister(instance registry.ServiceInstance) error {
+	path := toPath(instance)
+
+	if nil != e.client {
+		err := e.client.Delete(path)
+		e.services.Remove(instance.GetServiceName())
+		e.serviceInstance = nil
+		return err
+	}
+
+	return nil
+}
+
+// ----------------- discovery -------------------
+// GetDefaultPageSize will return the default page size
+func (e *etcdV3ServiceDiscovery) GetDefaultPageSize() int {
+	return registry.DefaultPageSize
+}
+
+// GetServices will return the all service names.
+func (e *etcdV3ServiceDiscovery) GetServices() *gxset.HashSet {
+	return e.services
+}
+
+// GetInstances will return all service instances with serviceName
+func (e *etcdV3ServiceDiscovery) GetInstances(serviceName string) []registry.ServiceInstance {
+
+	if nil != e.client {
+		// get keys and values
+		_, vList, err := e.client.GetChildrenKVList(toParentPath(serviceName))
+		if nil == err {
+			serviceInstances := make([]registry.ServiceInstance, 0, len(vList))
+			for _, v := range vList {
+				instance := &registry.DefaultServiceInstance{}
+				err = jsonutil.DecodeJSON([]byte(v), &instance)
+				if nil == err {
+					serviceInstances = append(serviceInstances, instance)
+				}
+			}
+			return serviceInstances
+		}
+		perrors.New(fmt.Sprintf("could not getChildrenKVList the err is:%v", err))

Review comment:
       `perrors.New` is not assigned to anyone?




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