From d9e366e74271e4ce7c3d206a721f2ddb71914fd9 Mon Sep 17 00:00:00 2001
From: yinheli <me@yinheli.com>
Date: Fri, 9 Jul 2021 10:30:55 +0800
Subject: [PATCH] core service use one etcd client instance

---
 core/xservice/client.go  |  7 ++----
 core/xservice/server.go  | 14 +++--------
 core/xservice/service.go | 53 ++++++++++++++++++++++++++--------------
 3 files changed, 39 insertions(+), 35 deletions(-)

diff --git a/core/xservice/client.go b/core/xservice/client.go
index 62325e2..9e874ac 100644
--- a/core/xservice/client.go
+++ b/core/xservice/client.go
@@ -29,11 +29,8 @@ func newClient(opts *Options) Client {
 	}
 
 	if os.Getenv(core.EnvEtcd) != "" {
-		cli, err := serviceEtcdClient()
-		if err != nil {
-			log.Fatal("etcd client", zap.Error(err))
-		}
-		client.resolver, err = resolver.NewBuilder(cli)
+		var err error
+		client.resolver, err = resolver.NewBuilder(serviceEtcdClient())
 		if err != nil {
 			log.Fatal("endpoints manager", zap.Error(err))
 		}
diff --git a/core/xservice/server.go b/core/xservice/server.go
index 865036b..f9667d9 100644
--- a/core/xservice/server.go
+++ b/core/xservice/server.go
@@ -365,11 +365,7 @@ func (t *serverImpl) registerGrpcServiceEtcd() {
 		cancel()
 		// deregister
 		log.Debug("deregister service")
-		client, err := serviceEtcdClient()
-		if err != nil {
-			return
-		}
-
+		client := serviceEtcdClient()
 		em, _ := endpoints.NewManager(client, core.ServiceRegisterKeyPrefix)
 
 		for _, service := range t.grpcServices {
@@ -390,11 +386,7 @@ func (t *serverImpl) doRegisterGrpcServiceEtcd(ctx context.Context) {
 		}
 	}()
 
-	client, err := serviceEtcdClient()
-	if err != nil {
-		l.Error("get client", zap.Error(err))
-		return
-	}
+	client := serviceEtcdClient()
 
 	ticker := time.NewTicker(time.Second * 5)
 	defer ticker.Stop()
@@ -437,7 +429,7 @@ func (t *serverImpl) doRegisterGrpcServiceEtcd(ctx context.Context) {
 					}
 				}
 			} else {
-				_, err = lease.KeepAliveOnce(context.Background(), id)
+				_, err := lease.KeepAliveOnce(context.Background(), id)
 				if err != nil {
 					id = 0
 				}
diff --git a/core/xservice/service.go b/core/xservice/service.go
index 8f7ea1e..7e8c258 100644
--- a/core/xservice/service.go
+++ b/core/xservice/service.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"strings"
+	"sync"
 	"time"
 
 	clientv3 "go.etcd.io/etcd/client/v3"
@@ -15,34 +16,48 @@ import (
 	"github.com/xinpianchang/xservice/pkg/log"
 )
 
+// serviceKey get full service key
 func serviceKey(serviceName string, desc *grpc.ServiceDesc) string {
 	host, _ := os.Hostname()
+	pid := os.Getpid()
 	if host == "" {
-		host = fmt.Sprint("unknown-host-pid-", os.Getpid())
+		host = "unknown-host"
 	}
-	return fmt.Sprint(serviceKeyPrefix(serviceName, desc), "/", host)
+	return fmt.Sprint(serviceKeyPrefix(serviceName, desc), "/", host, "-pid-", pid)
 }
 
+// serviceKeyPrefix get service key prefix
 func serviceKeyPrefix(serviceName string, desc *grpc.ServiceDesc) string {
 	return fmt.Sprint(core.ServiceRegisterKeyPrefix, "/", serviceName, "/", desc.ServiceName)
 }
 
-func serviceEtcdClient() (*clientv3.Client, error) {
-	endpoints := strings.Split(os.Getenv(core.EnvEtcd), ",")
+var (
+	_etcdClient     *clientv3.Client
+	_etcdClientOnce sync.Once
+)
 
-	cfg := clientv3.Config{
-		Endpoints:         endpoints,
-		DialTimeout:       time.Second * 5,
-		DialKeepAliveTime: time.Second * 5,
-		AutoSyncInterval:  time.Second * 10,
-		Logger:            log.Get().WithOptions(zap.IncreaseLevel(zapcore.ErrorLevel)),
-	}
-	if username := os.Getenv(core.EnvEtcdUser); username != "" {
-		cfg.Username = username
-	}
-	if password := os.Getenv(core.EnvEtcdPassword); password != "" {
-		cfg.Password = password
-	}
-	client, err := clientv3.New(cfg)
-	return client, err
+// serviceEtcdClient lazy init etcd client
+func serviceEtcdClient() *clientv3.Client {
+	_etcdClientOnce.Do(func() {
+		endpoints := strings.Split(os.Getenv(core.EnvEtcd), ",")
+		cfg := clientv3.Config{
+			Endpoints:         endpoints,
+			DialTimeout:       time.Second * 5,
+			DialKeepAliveTime: time.Second * 10,
+			AutoSyncInterval:  time.Second * 30,
+			Logger:            log.Get().WithOptions(zap.IncreaseLevel(zapcore.ErrorLevel)),
+		}
+		if username := os.Getenv(core.EnvEtcdUser); username != "" {
+			cfg.Username = username
+		}
+		if password := os.Getenv(core.EnvEtcdPassword); password != "" {
+			cfg.Password = password
+		}
+		client, err := clientv3.New(cfg)
+		if err != nil {
+			log.Fatal("serviceEtcdClient", zap.Error(err))
+		}
+		_etcdClient = client
+	})
+	return _etcdClient
 }