tianxiaoliang commented on a change in pull request #586: [SCB-1491] Example of instance access between multiple service-centers URL: https://github.com/apache/servicecomb-service-center/pull/586#discussion_r324566571
########## File path: syncer/samples/multi-servicecenters/servicecenter/hello-server/servicecenter/servicecenter.go ########## @@ -0,0 +1,244 @@ +/* + * 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 servicecenter + +import ( + "context" + "fmt" + "net/http" + "net/url" + "sync" + "time" + + "github.com/apache/servicecomb-service-center/pkg/client/sc" + "github.com/apache/servicecomb-service-center/pkg/log" + "github.com/apache/servicecomb-service-center/server/core/proto" + "github.com/apache/servicecomb-service-center/syncer/pkg/ticker" +) + +var ( + domainProject string + cli *sc.SCClient + once sync.Once + heartbeatInterval = 30 + providerCaches = &sync.Map{} + service *proto.MicroService + instance *proto.MicroServiceInstance +) + +func Start(ctx context.Context, conf *Config) (err error) { + once.Do(func() { + cli, err = sc.NewSCClient(sc.Config{Endpoints: conf.Registry.Endpoints}) + if err != nil { + log.Error("new service center client failed", err) + return + } + + if conf.Tenant != nil { + domainProject = conf.Tenant.Domain + "/" + conf.Tenant.Project + } + + consumerID := "" + if conf.Service != nil { + service, err = createService(ctx, conf.Service) + if err != nil { + return + } + + if conf.Service.Instance != nil { + instance, err = registerInstance(ctx, service.ServiceId, conf.Service.Instance) + if err != nil { + return + } + go heartbeat(ctx, instance) + } + consumerID = service.ServiceId + } + + + err = discoveryToCaches(ctx, consumerID, conf.Provider) + if err != nil { + return + } + go watchAndRenewCaches(ctx, conf.Provider) + }) + return +} + +func Stop(ctx context.Context) error { + if instance != nil { + // 注销微服务实例 + err := cli.UnregisterInstance(ctx, domainProject, instance.ServiceId, instance.InstanceId) + if err != nil { + return err + } + } + + // 实例注销后，服务中心清理数据需要一些时间，稍作延后 + time.Sleep(time.Second * 3) + // 注销微服务 + return cli.DeleteService(ctx, domainProject, service.ServiceId) +} + +func Do(ctx context.Context, method, addr string, headers http.Header, body []byte) (resp *http.Response, err error) { + raw, err := url.Parse(addr) + if err != nil { + return nil, err + } + endpoints, err := serverNameToEndpoints(raw.Hostname()) + + client, err := sc.NewLBClient(endpoints, (&sc.Config{Endpoints: endpoints}).Merge()) + if err != nil { + return nil, err + } + + return client.RestDoWithContext(ctx, method, raw.Path, headers, body) +} + +func createService(ctx context.Context, svc *MicroService) (*proto.MicroService, error) { + service := transformMicroService(svc) + + // 检测微服务是否存在 + serviceID, err := cli.ServiceExistence(ctx, domainProject, service.AppId, service.ServiceName, service.Version, "") + if serviceID == "" { + // 注册微服务 + serviceID, err = cli.CreateService(ctx, domainProject, service) + if err != nil { + return nil, err + } + } + service.ServiceId = serviceID + return service, nil +} + +func registerInstance(ctx context.Context, serviceID string, ins *Instance) (*proto.MicroServiceInstance, error) { + instance := transformInstance(ins) + instanceID, err := cli.RegisterInstance(ctx, domainProject, serviceID, instance) + if err != nil { + return nil, err + } + instance.ServiceId = serviceID + instance.InstanceId = instanceID + return instance, nil +} + +func heartbeat(ctx context.Context, ins *proto.MicroServiceInstance) { + // 启动定时器：间隔30s + t := ticker.NewTaskTicker(heartbeatInterval, func(ctx context.Context) { + // 定时发送心跳 + err := cli.Heartbeat(ctx, domainProject, ins.ServiceId, ins.InstanceId) + if err != nil { + log.Errorf(err, "send heartbeat failed, domain = %s, serviceID = %s, instanceID = %s", domainProject, ins.ServiceId, ins.InstanceId) + return + } + log.Debug("send heartbeat success") + }) + defer t.Stop() + t.Start(ctx) +} + +func discoveryToCaches(ctx context.Context, consumerID string, provider *MicroService) error { + service := transformMicroService(provider) + list, err := cli.DiscoveryInstances(ctx, domainProject, consumerID, service.AppId, service.ServiceName, service.Version) + if err != nil || len(list) == 0 { + return fmt.Errorf("provider not found, serviceName: %s appID: %s, version: %s", + provider.Name, provider.AppID, provider.Version) + } + // 缓存 provider 实例信息 + providerCaches.Store(provider.Name, list) + provider.ID = list[0].ServiceId + return nil +} + +func watchAndRenewCaches(ctx context.Context, provider *MicroService) { + err := cli.Watch(ctx, domainProject, provider.ID, func(result *proto.WatchInstanceResponse) { + log.Debug("reply from watch service") + list, ok := providerCaches.Load(result.Instance.ServiceId) + if !ok { + log.Infof("provider \"%s\" not found", result.Instance.ServiceId) + return + } + providerList := list.([]*proto.MicroServiceInstance) + + renew := false + for i, l := 0, len(providerList); i < l; i++ { Review comment: 4 level code block, plz simplify it ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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