[GitHub] [dubbo-go] zouyx commented on a change in pull request #701: Ftr: consul service discovery

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

zouyx commented on a change in pull request #701:
URL: https://github.com/apache/dubbo-go/pull/701#discussion_r482725036



##########
File path: registry/consul/service_discovery.go
##########
@@ -0,0 +1,421 @@
+/*
+ * 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 consul
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+import (
+	"github.com/dubbogo/gost/container/set"
+	"github.com/dubbogo/gost/page"
+	consul "github.com/hashicorp/consul/api"
+	"github.com/hashicorp/consul/api/watch"
+	perrors "github.com/pkg/errors"
+)
+
+import (
+	"github.com/apache/dubbo-go/common"
+	"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"
+)
+
+const (
+	enable = "enable"
+)
+
+var (
+	initLock sync.Mutex
+)
+
+// init will put the service discovery into extension
+func init() {
+	extension.SetServiceDiscovery(constant.CONSUL_KEY, newConsulServiceDiscovery)
+}
+
+// newConsulServiceDiscovery will create new service discovery instance
+// use double-check pattern to reduce race condition
+func newConsulServiceDiscovery(name string) (registry.ServiceDiscovery, error) {
+	sdc, ok := config.GetBaseConfig().GetServiceDiscoveries(name)
+	if !ok || len(sdc.RemoteRef) == 0 {
+		return nil, perrors.New("could not init the instance because the config is invalid")
+	}
+
+	remoteConfig, ok := config.GetBaseConfig().GetRemoteConfig(sdc.RemoteRef)
+	if !ok {
+		return nil, perrors.New("could not find the remote config for name: " + sdc.RemoteRef)
+	}
+
+	descriptor := fmt.Sprintf("consul-service-discovery[%s]", remoteConfig.Address)
+
+	return &consulServiceDiscovery{
+		address:    remoteConfig.Address,
+		descriptor: descriptor,
+		ttl:        make(map[string]chan struct{}),
+	}, nil
+}
+
+// consulServiceDiscovery is the implementation of service discovery based on consul.
+type consulServiceDiscovery struct {
+	group string
+	// descriptor is a short string about the basic information of this instance
+	descriptor string
+	// Consul client.
+	consulClient      *consul.Client
+	serviceUrl        common.URL
+	checkPassInterval int64
+	tag               string
+	tags              []string
+	address           string
+	ttl               map[string]chan struct{}
+	*consul.Config
+}
+
+func (csd *consulServiceDiscovery) Init(registryURL common.URL) error {
+	csd.serviceUrl = registryURL
+	csd.checkPassInterval = registryURL.GetParamInt(constant.CHECK_PASS_INTERVAL, constant.DEFAULT_CHECK_PASS_INTERVAL)
+	csd.tag = registryURL.GetParam(constant.QUERY_TAG, "")
+	csd.tags = strings.Split(registryURL.GetParam("tags", ""), ",")
+	aclToken := registryURL.GetParam(constant.ACL_TOKEN, "")
+	csd.Config = &consul.Config{Address: csd.address, Token: aclToken}
+	client, err := consul.NewClient(csd.Config)
+	if err != nil {
+		return perrors.WithMessage(err, "create consul client failed.")
+	}
+	csd.consulClient = client
+	return nil
+}
+
+func (csd *consulServiceDiscovery) String() string {
+	return csd.descriptor
+}
+
+func (csd *consulServiceDiscovery) Destroy() error {
+	csd.consulClient = nil
+	for _, t := range csd.ttl {
+		close(t)
+	}
+	csd.ttl = nil
+	return nil
+}
+
+func (csd *consulServiceDiscovery) Register(instance registry.ServiceInstance) error {
+	ins, _ := csd.buildRegisterInstance(instance)
+	err := csd.consulClient.Agent().ServiceRegister(ins)
+	if err != nil {
+		logger.Errorf("consul register the instance %s fail:%v", instance.GetServiceName(), err)
+		return perrors.WithMessage(err, "consul could not register the instance. "+instance.GetServiceName())
+	}
+
+	return csd.registerTtl(instance)
+}
+
+func (csd *consulServiceDiscovery) registerTtl(instance registry.ServiceInstance) error {
+	checkID := buildID(instance)
+
+	stopChan := make(chan struct{})
+	csd.ttl[buildID(instance)] = stopChan
+
+	period := time.Duration(csd.checkPassInterval/8) * time.Millisecond
+	timer := time.NewTimer(period)
+	go func() {
+		for {
+			select {
+			case <-timer.C:
+				timer.Reset(period)
+				err := csd.consulClient.Agent().PassTTL(fmt.Sprintf("service:%s", checkID), "")
+				if err != nil {
+					logger.Warnf("pass ttl heartbeat fail:%v", err)
+					break
+				}
+				logger.Debugf("passed ttl heartbeat for %s", checkID)
+				break
+			case <-stopChan:
+				logger.Info("ttl %s for service %s is stopped", checkID, instance.GetServiceName())
+				return
+			}
+		}
+	}()
+	return nil
+}
+
+func (csd *consulServiceDiscovery) Update(instance registry.ServiceInstance) error {
+	ins, _ := csd.buildRegisterInstance(instance)
+	err := csd.consulClient.Agent().ServiceDeregister(buildID(instance))
+	if err != nil {
+		logger.Warnf("unregister instance %s fail:%v", instance.GetServiceName(), err)
+	}
+	return csd.consulClient.Agent().ServiceRegister(ins)
+}
+
+func (csd *consulServiceDiscovery) Unregister(instance registry.ServiceInstance) error {
+	err := csd.consulClient.Agent().ServiceDeregister(buildID(instance))
+	if err != nil {
+		logger.Errorf("unregister service instance %s,error: %v", instance.GetId(), err)
+		return err
+	}
+	stopChanel, ok := csd.ttl[buildID(instance)]
+	if !ok {
+		logger.Warnf("ttl for service instance %s didn't exist", instance.GetId())
+		return nil
+	}
+	close(stopChanel)
+	delete(csd.ttl, buildID(instance))
+	return nil

Review comment:
       The same to `Destory` method

##########
File path: registry/consul/service_discovery.go
##########
@@ -0,0 +1,421 @@
+/*
+ * 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 consul
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+import (
+	"github.com/dubbogo/gost/container/set"
+	"github.com/dubbogo/gost/page"
+	consul "github.com/hashicorp/consul/api"
+	"github.com/hashicorp/consul/api/watch"
+	perrors "github.com/pkg/errors"
+)
+
+import (
+	"github.com/apache/dubbo-go/common"
+	"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"
+)
+
+const (
+	enable = "enable"
+)
+
+var (
+	initLock sync.Mutex
+)
+
+// init will put the service discovery into extension
+func init() {
+	extension.SetServiceDiscovery(constant.CONSUL_KEY, newConsulServiceDiscovery)
+}
+
+// newConsulServiceDiscovery will create new service discovery instance
+// use double-check pattern to reduce race condition
+func newConsulServiceDiscovery(name string) (registry.ServiceDiscovery, error) {
+	sdc, ok := config.GetBaseConfig().GetServiceDiscoveries(name)
+	if !ok || len(sdc.RemoteRef) == 0 {
+		return nil, perrors.New("could not init the instance because the config is invalid")
+	}
+
+	remoteConfig, ok := config.GetBaseConfig().GetRemoteConfig(sdc.RemoteRef)
+	if !ok {
+		return nil, perrors.New("could not find the remote config for name: " + sdc.RemoteRef)
+	}
+
+	descriptor := fmt.Sprintf("consul-service-discovery[%s]", remoteConfig.Address)
+
+	return &consulServiceDiscovery{
+		address:    remoteConfig.Address,
+		descriptor: descriptor,
+		ttl:        make(map[string]chan struct{}),
+	}, nil
+}
+
+// consulServiceDiscovery is the implementation of service discovery based on consul.
+type consulServiceDiscovery struct {
+	group string
+	// descriptor is a short string about the basic information of this instance
+	descriptor string
+	// Consul client.
+	consulClient      *consul.Client
+	serviceUrl        common.URL
+	checkPassInterval int64
+	tag               string
+	tags              []string
+	address           string
+	ttl               map[string]chan struct{}
+	*consul.Config
+}
+
+func (csd *consulServiceDiscovery) Init(registryURL common.URL) error {
+	csd.serviceUrl = registryURL
+	csd.checkPassInterval = registryURL.GetParamInt(constant.CHECK_PASS_INTERVAL, constant.DEFAULT_CHECK_PASS_INTERVAL)
+	csd.tag = registryURL.GetParam(constant.QUERY_TAG, "")
+	csd.tags = strings.Split(registryURL.GetParam("tags", ""), ",")
+	aclToken := registryURL.GetParam(constant.ACL_TOKEN, "")
+	csd.Config = &consul.Config{Address: csd.address, Token: aclToken}
+	client, err := consul.NewClient(csd.Config)
+	if err != nil {
+		return perrors.WithMessage(err, "create consul client failed.")
+	}
+	csd.consulClient = client
+	return nil
+}
+
+func (csd *consulServiceDiscovery) String() string {
+	return csd.descriptor
+}
+
+func (csd *consulServiceDiscovery) Destroy() error {
+	csd.consulClient = nil
+	for _, t := range csd.ttl {
+		close(t)
+	}
+	csd.ttl = nil
+	return nil

Review comment:
       Should add a lock and flag for this block .
   
   For ensure it won‘t cause concurrency problem.
   
   Because channel can‘t close twice.

##########
File path: registry/consul/service_discovery.go
##########
@@ -0,0 +1,421 @@
+/*
+ * 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 consul
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+import (
+	"github.com/dubbogo/gost/container/set"
+	"github.com/dubbogo/gost/page"
+	consul "github.com/hashicorp/consul/api"
+	"github.com/hashicorp/consul/api/watch"
+	perrors "github.com/pkg/errors"
+)
+
+import (
+	"github.com/apache/dubbo-go/common"
+	"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"
+)
+
+const (
+	enable = "enable"
+)
+
+var (
+	initLock sync.Mutex
+)
+
+// init will put the service discovery into extension
+func init() {
+	extension.SetServiceDiscovery(constant.CONSUL_KEY, newConsulServiceDiscovery)
+}
+
+// newConsulServiceDiscovery will create new service discovery instance
+// use double-check pattern to reduce race condition
+func newConsulServiceDiscovery(name string) (registry.ServiceDiscovery, error) {
+	sdc, ok := config.GetBaseConfig().GetServiceDiscoveries(name)
+	if !ok || len(sdc.RemoteRef) == 0 {
+		return nil, perrors.New("could not init the instance because the config is invalid")
+	}
+
+	remoteConfig, ok := config.GetBaseConfig().GetRemoteConfig(sdc.RemoteRef)
+	if !ok {
+		return nil, perrors.New("could not find the remote config for name: " + sdc.RemoteRef)
+	}
+
+	descriptor := fmt.Sprintf("consul-service-discovery[%s]", remoteConfig.Address)
+
+	return &consulServiceDiscovery{
+		address:    remoteConfig.Address,
+		descriptor: descriptor,
+		ttl:        make(map[string]chan struct{}),
+	}, nil
+}
+
+// consulServiceDiscovery is the implementation of service discovery based on consul.
+type consulServiceDiscovery struct {
+	group string
+	// descriptor is a short string about the basic information of this instance
+	descriptor string
+	// Consul client.
+	consulClient      *consul.Client
+	serviceUrl        common.URL
+	checkPassInterval int64
+	tag               string
+	tags              []string
+	address           string
+	ttl               map[string]chan struct{}
+	*consul.Config
+}
+
+func (csd *consulServiceDiscovery) Init(registryURL common.URL) error {
+	csd.serviceUrl = registryURL
+	csd.checkPassInterval = registryURL.GetParamInt(constant.CHECK_PASS_INTERVAL, constant.DEFAULT_CHECK_PASS_INTERVAL)
+	csd.tag = registryURL.GetParam(constant.QUERY_TAG, "")
+	csd.tags = strings.Split(registryURL.GetParam("tags", ""), ",")
+	aclToken := registryURL.GetParam(constant.ACL_TOKEN, "")
+	csd.Config = &consul.Config{Address: csd.address, Token: aclToken}
+	client, err := consul.NewClient(csd.Config)
+	if err != nil {
+		return perrors.WithMessage(err, "create consul client failed.")
+	}
+	csd.consulClient = client
+	return nil
+}
+
+func (csd *consulServiceDiscovery) String() string {
+	return csd.descriptor
+}
+
+func (csd *consulServiceDiscovery) Destroy() error {
+	csd.consulClient = nil
+	for _, t := range csd.ttl {
+		close(t)
+	}
+	csd.ttl = nil
+	return nil
+}
+
+func (csd *consulServiceDiscovery) Register(instance registry.ServiceInstance) error {
+	ins, _ := csd.buildRegisterInstance(instance)
+	err := csd.consulClient.Agent().ServiceRegister(ins)
+	if err != nil {
+		logger.Errorf("consul register the instance %s fail:%v", instance.GetServiceName(), err)
+		return perrors.WithMessage(err, "consul could not register the instance. "+instance.GetServiceName())
+	}
+
+	return csd.registerTtl(instance)
+}
+
+func (csd *consulServiceDiscovery) registerTtl(instance registry.ServiceInstance) error {
+	checkID := buildID(instance)
+
+	stopChan := make(chan struct{})
+	csd.ttl[buildID(instance)] = stopChan
+
+	period := time.Duration(csd.checkPassInterval/8) * time.Millisecond
+	timer := time.NewTimer(period)
+	go func() {
+		for {
+			select {
+			case <-timer.C:
+				timer.Reset(period)
+				err := csd.consulClient.Agent().PassTTL(fmt.Sprintf("service:%s", checkID), "")
+				if err != nil {
+					logger.Warnf("pass ttl heartbeat fail:%v", err)
+					break
+				}
+				logger.Debugf("passed ttl heartbeat for %s", checkID)
+				break
+			case <-stopChan:
+				logger.Info("ttl %s for service %s is stopped", checkID, instance.GetServiceName())
+				return
+			}
+		}
+	}()
+	return nil
+}
+
+func (csd *consulServiceDiscovery) Update(instance registry.ServiceInstance) error {
+	ins, _ := csd.buildRegisterInstance(instance)
+	err := csd.consulClient.Agent().ServiceDeregister(buildID(instance))
+	if err != nil {
+		logger.Warnf("unregister instance %s fail:%v", instance.GetServiceName(), err)
+	}
+	return csd.consulClient.Agent().ServiceRegister(ins)
+}
+
+func (csd *consulServiceDiscovery) Unregister(instance registry.ServiceInstance) error {
+	err := csd.consulClient.Agent().ServiceDeregister(buildID(instance))
+	if err != nil {
+		logger.Errorf("unregister service instance %s,error: %v", instance.GetId(), err)
+		return err
+	}
+	stopChanel, ok := csd.ttl[buildID(instance)]
+	if !ok {
+		logger.Warnf("ttl for service instance %s didn't exist", instance.GetId())
+		return nil
+	}
+	close(stopChanel)
+	delete(csd.ttl, buildID(instance))
+	return nil
+}
+
+func (csd *consulServiceDiscovery) GetDefaultPageSize() int {
+	return registry.DefaultPageSize
+}
+
+func (csd *consulServiceDiscovery) GetServices() *gxset.HashSet {
+
+	var res = gxset.NewSet()
+	services, _, err := csd.consulClient.Catalog().Services(nil)
+	if err != nil {
+		logger.Errorf("get services,error: %v", err)
+		return res
+	}
+
+	for service, _ := range services {
+		res.Add(service)
+	}
+	return res
+
+}
+
+// encodeConsulMetadata because consul validate key strictly.
+func encodeConsulMetadata(metadata map[string]string) map[string]string {
+	consulMetadata := make(map[string]string, 8)
+	if metadata == nil {
+		return consulMetadata
+	}
+	encoder := base64.RawStdEncoding
+	for k, v := range metadata {
+		consulMetadata[encoder.EncodeToString([]byte(k))] = v
+	}
+	return consulMetadata
+}
+
+// nolint
+func decodeConsulMetadata(metadata map[string]string) map[string]string {
+	dubboMetadata := make(map[string]string, 8)
+	if metadata == nil {
+		return dubboMetadata
+	}
+	encoder := base64.RawStdEncoding
+	for k, v := range metadata {
+		kBytes, err := encoder.DecodeString(k)
+		if err != nil {
+			logger.Warnf("can not decoded consul metadata key %s", k)
+			continue
+		}
+		dubboMetadata[string(kBytes)] = v
+	}
+	return dubboMetadata
+}
+
+func (csd *consulServiceDiscovery) GetInstances(serviceName string) []registry.ServiceInstance {
+	waitTime := csd.serviceUrl.GetParamInt(constant.WATCH_TIMEOUT, constant.DEFAULT_WATCH_TIMEOUT) / 1000
+	instances, _, err := csd.consulClient.Health().Service(serviceName, csd.tag, true, &consul.QueryOptions{
+		WaitTime: time.Duration(waitTime),
+	})
+	if err != nil {
+		logger.Errorf("get instances for service %s,error: %v", serviceName, err)
+		return nil
+	}
+
+	res := make([]registry.ServiceInstance, 0, len(instances))
+	for _, ins := range instances {
+		metadata := ins.Service.Meta
+
+		// enable status
+		enableStr := metadata[enable]
+		delete(metadata, enable)
+		enable, _ := strconv.ParseBool(enableStr)
+		metadata = decodeConsulMetadata(metadata)
+
+		// health status
+		status := ins.Checks.AggregatedStatus()
+		healthy := false
+		if status == consul.HealthPassing {
+			healthy = true
+		}
+		res = append(res, &registry.DefaultServiceInstance{
+			Id:          ins.Service.ID,
+			ServiceName: ins.Service.Service,
+			Host:        ins.Service.Address,
+			Port:        ins.Service.Port,
+			Enable:      enable,
+			Healthy:     healthy,
+			Metadata:    metadata,
+		})
+	}
+
+	return res
+}
+
+func (csd *consulServiceDiscovery) GetInstancesByPage(serviceName string, offset int, pageSize int) gxpage.Pager {
+	all := csd.GetInstances(serviceName)
+	res := make([]interface{}, 0, pageSize)
+	for i := offset; i < len(all) && i < offset+pageSize; i++ {
+		res = append(res, all[i])
+	}
+	return gxpage.New(offset, pageSize, res, len(all))
+}
+
+func (csd *consulServiceDiscovery) GetHealthyInstancesByPage(serviceName string, offset int, pageSize int, healthy bool) gxpage.Pager {
+	all := csd.GetInstances(serviceName)
+	res := make([]interface{}, 0, pageSize)
+	// could not use res = all[a:b] here because the res should be []interface{}, not []ServiceInstance
+	var (
+		i     = offset
+		count = 0
+	)
+	for i < len(all) && count < pageSize {
+		ins := all[i]
+		if ins.IsHealthy() == healthy {
+			res = append(res, all[i])
+			count++
+		}
+		i++
+	}
+	return gxpage.New(offset, pageSize, res, len(all))
+}
+
+func (csd *consulServiceDiscovery) GetRequestInstances(serviceNames []string, offset int, requestedSize int) map[string]gxpage.Pager {
+	res := make(map[string]gxpage.Pager, len(serviceNames))
+	for _, name := range serviceNames {
+		res[name] = csd.GetInstancesByPage(name, offset, requestedSize)
+	}
+	return res
+}
+
+func (csd *consulServiceDiscovery) AddListener(listener *registry.ServiceInstancesChangedListener) error {
+
+	params := make(map[string]interface{}, 8)
+	params["type"] = "service"
+	params["service"] = listener.ServiceName
+	params["passingonly"] = true
+	plan, err := watch.Parse(params)
+	if err != nil {
+		logger.Errorf("add listener for service %s,error:%v", listener.ServiceName, err)
+		return err
+	}
+
+	plan.Handler = func(idx uint64, raw interface{}) {
+		services, ok := raw.([]*consul.ServiceEntry)
+		if !ok {
+			err = perrors.New("handler get non ServiceEntry type parameter")
+			return
+		}
+		instances := make([]registry.ServiceInstance, 0, len(services))
+		for _, ins := range services {
+			metadata := ins.Service.Meta
+
+			// enable status
+			enableStr := metadata[enable]
+			delete(metadata, enable)
+			enable, _ := strconv.ParseBool(enableStr)
+
+			// health status
+			status := ins.Checks.AggregatedStatus()
+			healthy := false
+			if status == consul.HealthPassing {
+				healthy = true
+			}
+			instances = append(instances, &registry.DefaultServiceInstance{
+				Id:          ins.Service.ID,
+				ServiceName: ins.Service.Service,
+				Host:        ins.Service.Address,
+				Port:        ins.Service.Port,
+				Enable:      enable,
+				Healthy:     healthy,
+				Metadata:    metadata,
+			})
+		}
+		e := csd.DispatchEventForInstances(listener.ServiceName, instances)
+		if e != nil {
+			logger.Errorf("Dispatching event got exception, service name: %s, err: %v", listener.ServiceName, err)
+		}
+	}
+	go func() {
+		err = plan.RunWithConfig(csd.Config.Address, csd.Config)
+		if err != nil {
+			logger.Error("consul plan run failure!error:%v", err)
+		}
+	}()
+	return nil
+}
+
+func (csd *consulServiceDiscovery) DispatchEventByServiceName(serviceName string) error {
+	return csd.DispatchEventForInstances(serviceName, csd.GetInstances(serviceName))
+}
+
+func (csd *consulServiceDiscovery) DispatchEventForInstances(serviceName string, instances []registry.ServiceInstance) error {
+	return csd.DispatchEvent(registry.NewServiceInstancesChangedEvent(serviceName, instances))
+}
+
+func (csd *consulServiceDiscovery) DispatchEvent(event *registry.ServiceInstancesChangedEvent) error {
+	extension.GetGlobalDispatcher().Dispatch(event)
+	return nil
+}
+
+func (csd *consulServiceDiscovery) buildRegisterInstance(instance registry.ServiceInstance) (*consul.AgentServiceRegistration, error) {
+	metadata := instance.GetMetadata()
+	metadata = encodeConsulMetadata(metadata)
+	metadata[enable] = strconv.FormatBool(instance.IsEnable())
+	// check
+	check := csd.buildCheck(instance)
+
+	return &consul.AgentServiceRegistration{
+		ID:      buildID(instance),
+		Name:    instance.GetServiceName(),
+		Port:    instance.GetPort(),
+		Address: instance.GetHost(),
+		Meta:    metadata,
+		Check:   &check,
+	}, nil
+}
+
+func (csd *consulServiceDiscovery) buildCheck(instance registry.ServiceInstance) consul.AgentServiceCheck {
+
+	deregister, ok := instance.GetMetadata()[constant.DEREGISTER_AFTER]
+	if !ok || deregister == "" {

Review comment:
       ```suggestion
   	if !ok || len(deregister)==0 {
   ```




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