feat: add retry feature for etcd

etcd/example/server/retry/main.go

@@ -0,0 +1,51 @@
+// Copyright 2021 CloudWeGo Authors.
+//
+// Licensed 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 main
+
+import (
+	"context"
+	"time"
+
+	"github.com/cloudwego/hertz/pkg/app"
+	"github.com/cloudwego/hertz/pkg/app/server"
+	"github.com/cloudwego/hertz/pkg/app/server/registry"
+	"github.com/cloudwego/hertz/pkg/common/utils"
+	"github.com/cloudwego/hertz/pkg/protocol/consts"
+	"github.com/hertz-contrib/registry/etcd"
+)
+
+func main() {
+	r, _ := etcd.NewEtcdRegistry(
+		[]string{"127.0.0.1:2379"},
+		etcd.WithMaxAttemptTimes(10),
+		etcd.WithObserveDelay(20*time.Second),
+		etcd.WithRetryDelay(5*time.Second),
+	)
+
+	addr := "127.0.0.1:8888"
+	h := server.Default(
+		server.WithHostPorts(addr),
+		server.WithRegistry(r, &registry.Info{
+			ServiceName: "hertz.test.demo",
+			Addr:        utils.NewNetAddr("tcp", addr),
+			Weight:      10,
+			Tags:        nil,
+		}),
+	)
+	h.GET("/ping", func(_ context.Context, ctx *app.RequestContext) {
+		ctx.JSON(consts.StatusOK, utils.H{"ping": "pong2"})
+	})
+	h.Spin()
+}

etcd/common.go → etcd/option.go

@@ -22,6 +22,7 @@ import (
 	"io/ioutil"
 	"os"
 	"strconv"
+	"time"
 
 	"github.com/cloudwego/hertz/pkg/app/server/registry"
 	"github.com/cloudwego/hertz/pkg/common/hlog"
@@ -32,6 +33,50 @@ const (
 	defaultTTL = 60
 )
 
+type option struct {
+	// etcd client config
+	etcdCfg  *clientv3.Config
+	retryCfg *retryCfg
+}
+
+type retryCfg struct {
+	// The maximum number of call attempt times, including the initial call
+	maxAttemptTimes uint
+	// The retryCfg delay time
+	observeDelay time.Duration
+	// The delay time of observing etcd key
+	retryDelay time.Duration
+}
+
+type Option func(o *option)
+
+// WithMaxAttemptTimes sets the maximum number of call attempt times, including the initial call
+func WithMaxAttemptTimes(maxAttemptTimes uint) Option {
+	return func(o *option) {
+		o.retryCfg.maxAttemptTimes = maxAttemptTimes
+	}
+}
+
+// WithObserveDelay sets the delay time of observing etcd key
+func WithObserveDelay(observeDelay time.Duration) Option {
+	return func(o *option) {
+		o.retryCfg.observeDelay = observeDelay
+	}
+}
+
+// WithRetryDelay sets the delay time of retryCfg
+func WithRetryDelay(t time.Duration) Option {
+	return func(o *option) {
+		o.retryCfg.retryDelay = t
+	}
+}
+
+func (o *option) apply(opts ...Option) {
+	for _, opt := range opts {
+		opt(o)
+	}
+}
+
 // instanceInfo used to stored service basic info in etcd.
 type instanceInfo struct {
 	Network string            `json:"network"`
@@ -74,25 +119,22 @@ func getTTL() int64 {
 	return ttl
 }
 
-// Option sets options such as username, tls etc.
-type Option func(cfg *clientv3.Config)
-
 // WithTLSOpt returns a option that authentication by tls/ssl.
 func WithTLSOpt(certFile, keyFile, caFile string) Option {
-	return func(cfg *clientv3.Config) {
+	return func(o *option) {
 		tlsCfg, err := newTLSConfig(certFile, keyFile, caFile, "")
 		if err != nil {
 			hlog.Errorf("HERTZ: tls failed with err: %v , skipping tls.", err)
 		}
-		cfg.TLS = tlsCfg
+		o.etcdCfg.TLS = tlsCfg
 	}
 }
 
 // WithAuthOpt returns an option that authentication by username and password.
 func WithAuthOpt(username, password string) Option {
-	return func(cfg *clientv3.Config) {
-		cfg.Username = username
-		cfg.Password = password
+	return func(o *option) {
+		o.etcdCfg.Username = username
+		o.etcdCfg.Password = password
 	}
 }
 

etcd/readme.md

@@ -191,6 +191,72 @@ func main() {
 	}
 }
 ```
+## Retry
+
+After the service is registered to `ETCD`, it will regularly check the status of the service. If any abnormal status is found, it will try to register the service again. `observeDelay` is the delay time for checking the service status under normal conditions, and `retryDelay` is the delay time for attempting to register the service after disconnecting.
+
+### Default Retry Config
+
+```go
+type retryCfg struct {
+	// The maximum number of call attempt times, including the initial call
+	maxAttemptTimes uint
+	// observeDelay is the delay time for checking the service status under normal conditions
+	observeDelay time.Duration
+	// The delay time of observing etcd key
+	retryDelay time.Duration
+}
+```
+
+| Config Name         | Default Value    | Description                                                                               |
+|:--------------------|:-----------------|:------------------------------------------------------------------------------------------|
+| WithMaxAttemptTimes | 5                | Used to set the maximum number of attempts, if 0, it means infinite attempts              |
+| WithObserveDelay    | 30 * time.Second | Used to set the delay time for checking service status under normal connection conditions |
+| WithRetryDelay      | 10 * time.Second | Used to set the retry delay time after disconnecting                                      |
+
+### Example
+
+```go
+package main
+
+import (
+	"context"
+	"time"
+
+	"github.com/cloudwego/hertz/pkg/app"
+	"github.com/cloudwego/hertz/pkg/app/server"
+	"github.com/cloudwego/hertz/pkg/app/server/registry"
+	"github.com/cloudwego/hertz/pkg/common/utils"
+	"github.com/cloudwego/hertz/pkg/protocol/consts"
+	"github.com/hertz-contrib/registry/etcd"
+)
+
+func main() {
+	r, _ := etcd.NewEtcdRegistry(
+		[]string{"127.0.0.1:2379"},
+		etcd.WithMaxAttemptTimes(10),
+		etcd.WithObserveDelay(20*time.Second),
+		etcd.WithRetryDelay(5*time.Second),
+	)
+
+	addr := "127.0.0.1:8888"
+	h := server.Default(
+		server.WithHostPorts(addr),
+		server.WithRegistry(r, &registry.Info{
+			ServiceName: "hertz.test.demo",
+			Addr:        utils.NewNetAddr("tcp", addr),
+			Weight:      10,
+			Tags:        nil,
+		}),
+	)
+	h.GET("/ping", func(_ context.Context, ctx *app.RequestContext) {
+		ctx.JSON(consts.StatusOK, utils.H{"ping": "pong2"})
+	})
+	h.Spin()
+}
+
+```
+
 ## How to Dynamically specify ip and port
 
 To dynamically specify an IP and port, one should first set the environment variables `HERTZ_IP_TO_REGISTRY` and `HERTZ_PORT_TO_REGISTRY`. If these variables are not set, the system defaults to using the service's listening IP and port. Notably, if the service's listening IP is either not set or set to "::", the system will automatically retrieve and use the machine's IPV4 address.

etcd/registry.go

@@ -38,10 +38,13 @@ const (
 )
 
 type etcdRegistry struct {
-	etcdClient *clientv3.Client
-	leaseTTL   int64
-	meta       *registerMeta
-	mu         sync.Mutex
+	etcdClient  *clientv3.Client
+	retryConfig *retryCfg
+
+	leaseTTL int64
+	meta     *registerMeta
+	mu       sync.Mutex
+	stop     chan struct{}
 }
 
 type registerMeta struct {
@@ -52,19 +55,27 @@ type registerMeta struct {
 
 // NewEtcdRegistry creates a etcd based registry.
 func NewEtcdRegistry(endpoints []string, opts ...Option) (registry.Registry, error) {
-	cfg := clientv3.Config{
-		Endpoints: endpoints,
-	}
-	for _, opt := range opts {
-		opt(&cfg)
+	cfg := &option{
+		etcdCfg: &clientv3.Config{
+			Endpoints: endpoints,
+		},
+		retryCfg: &retryCfg{
+			maxAttemptTimes: 5,
+			observeDelay:    30 * time.Second,
+			retryDelay:      10 * time.Second,
+		},
 	}
-	etcdClient, err := clientv3.New(cfg)
+	cfg.apply(opts...)
+
+	etcdClient, err := clientv3.New(*cfg.etcdCfg)
 	if err != nil {
 		return nil, err
 	}
 	return &etcdRegistry{
-		etcdClient: etcdClient,
-		leaseTTL:   getTTL(),
+		etcdClient:  etcdClient,
+		leaseTTL:    getTTL(),
+		retryConfig: cfg.retryCfg,
+		stop:        make(chan struct{}, 1),
 	}, nil
 }
 
@@ -84,12 +95,13 @@ func (e *etcdRegistry) Register(info *registry.Info) error {
 		leaseID: leaseID,
 	}
 	meta.ctx, meta.cancel = context.WithCancel(context.Background())
-	if err := e.keepalive(&meta); err != nil {
+	if err := e.keepalive(meta); err != nil {
 		return err
 	}
 	e.mu.Lock()
 	e.meta = &meta
 	e.mu.Unlock()
+
 	return nil
 }
 
@@ -133,7 +145,16 @@ func (e *etcdRegistry) register(info *registry.Info, leaseID clientv3.LeaseID) e
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*3)
 	defer cancel()
 	_, err = e.etcdClient.Put(ctx, serviceKey(info.ServiceName, addr), string(val), clientv3.WithLease(leaseID))
-	return err
+	if err != nil {
+		return err
+	}
+
+	// retry start
+	go func(key, val string) {
+		e.keepRegister(key, val, e.retryConfig)
+	}(serviceKey(info.ServiceName, addr), string(val))
+
+	return nil
 }
 
 func (e *etcdRegistry) deregister(info *registry.Info) error {
@@ -144,11 +165,15 @@ func (e *etcdRegistry) deregister(info *registry.Info) error {
 		return err
 	}
 	_, err = e.etcdClient.Delete(ctx, serviceKey(info.ServiceName, addr))
-	return err
+	if err != nil {
+		return err
+	}
+	e.stop <- struct{}{}
+	return nil
 }
 
 // keepalive keep the lease alive
-func (e *etcdRegistry) keepalive(meta *registerMeta) error {
+func (e *etcdRegistry) keepalive(meta registerMeta) error {
 	keepAlive, err := e.etcdClient.KeepAlive(meta.ctx, meta.leaseID)
 	if err != nil {
 		return err
@@ -168,6 +193,68 @@ func (e *etcdRegistry) keepalive(meta *registerMeta) error {
 	return nil
 }
 
+// keepRegister keep register service by retryConfig
+func (e *etcdRegistry) keepRegister(key, val string, retryConfig *retryCfg) {
+	var failedTimes uint
+	delay := retryConfig.observeDelay
+	// if maxAttemptTimes is 0, keep register forever
+	for retryConfig.maxAttemptTimes == 0 || failedTimes < retryConfig.maxAttemptTimes {
+		select {
+		case _, ok := <-e.stop:
+			if !ok {
+				close(e.stop)
+			}
+			hlog.Infof("stop keep register service %s", key)
+			return
+		case <-time.After(delay):
+		}
+
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second*3)
+		resp, err := e.etcdClient.Get(ctx, key)
+		cancel()
+
+		if err != nil {
+			hlog.Warnf("keep register get %s failed with err: %v", key, err)
+			delay = retryConfig.retryDelay
+			failedTimes++
+			continue
+		}
+
+		if len(resp.Kvs) == 0 {
+			hlog.Infof("keep register service %s", key)
+			delay = retryConfig.retryDelay
+			leaseID, err := e.grantLease()
+			if err != nil {
+				hlog.Warnf("keep register grant lease %s failed with err: %v", key, err)
+				failedTimes++
+				continue
+			}
+
+			_, err = e.etcdClient.Put(ctx, key, val, clientv3.WithLease(leaseID))
+			if err != nil {
+				hlog.Warnf("keep register put %s failed with err: %v", key, err)
+				failedTimes++
+				continue
+			}
+
+			meta := registerMeta{
+				leaseID: leaseID,
+			}
+			meta.ctx, meta.cancel = context.WithCancel(context.Background())
+			if err := e.keepalive(meta); err != nil {
+				hlog.Warnf("keep register keepalive %s failed with err: %v", key, err)
+				failedTimes++
+				continue
+			}
+			e.meta.cancel()
+			e.meta = &meta
+			delay = retryConfig.observeDelay
+		}
+		failedTimes = 0
+	}
+	hlog.Errorf("keep register service %s failed times:%d", key, failedTimes)
+}
+
 // getAddressOfRegistration returns the address of the service registration.
 func (e *etcdRegistry) getAddressOfRegistration(info *registry.Info) (string, error) {
 	host, port, err := net.SplitHostPort(info.Addr.String())