參考博客

1、服務實例接口與默認實現

type ServiceInstance interface {// 獲取服務實例的唯一IDGetInstanceId() string// 獲取服務IDGetServiceId() string// 獲取服務實例的主機名或IP地址GetHost() string// 獲取服務實例的端口號GetPort() int// 判斷服務實例是否使用HTTPSIsSecure() bool// 獲取服務實例的元數據(鍵值對形式)GetMetadata() map[string]string
}type DefaultServiceInstance struct {InstanceId stringServiceId  stringHost       stringPort       intSecure     boolMetadata   map[string]string
}// 構造函數
func NewDefaultServiceInstance(serviceId string, host string, port int, secure bool,metadata map[string]string, instanceId string) (*DefaultServiceInstance, error) {// 如果沒有傳入 IP 則獲取一下，這個方法在多網卡的情況下，并不好用if len(host) == 0 {localIP, err := util.GetLocalIP()if err != nil {return nil, err}host = localIP}//若instanceId為空，自動生成“服務ID-時間戳-隨機數（1000-9999）”if len(instanceId) == 0 {instanceId = serviceId + "-" + strconv.FormatInt(time.Now().Unix(), 10) + "-" + strconv.Itoa(rand.Intn(9000)+1000)}return &DefaultServiceInstance{InstanceId: instanceId, ServiceId: serviceId, Host: host, Port: port, Secure: secure, Metadata: metadata}, nil
}func (serviceInstance DefaultServiceInstance) GetInstanceId() string {return serviceInstance.InstanceId
}func (serviceInstance DefaultServiceInstance) GetServiceId() string {return serviceInstance.ServiceId
}func (serviceInstance DefaultServiceInstance) GetHost() string {return serviceInstance.Host
}func (serviceInstance DefaultServiceInstance) GetPort() int {return serviceInstance.Port
}func (serviceInstance DefaultServiceInstance) IsSecure() bool {return serviceInstance.Secure
}func (serviceInstance DefaultServiceInstance) GetMetadata() map[string]string {return serviceInstance.Metadata
}

2、定義服務注冊和剔除的方法

type ServiceRegistry interface {Register(serviceInstance cloud.ServiceInstance) boolDeregister()
}

具體實現：

import ("errors""fmt""github.com/hashicorp/consul/api""strconv""unsafe"
)type consulServiceRegistry struct {// 服務實例緩存（服務ID->實例ID->實例）serviceInstances     map[string]map[string]cloud.ServiceInstance//Consul客戶端client               api.Client//當前本地服務實例localServiceInstance cloud.ServiceInstance
}func (c consulServiceRegistry) Register(serviceInstance cloud.ServiceInstance) bool {// 創建注冊到consul的服務到registration := new(api.AgentServiceRegistration)registration.ID = serviceInstance.GetInstanceId()registration.Name = serviceInstance.GetServiceId()registration.Port = serviceInstance.GetPort()var tags []stringif serviceInstance.IsSecure() {tags = append(tags, "secure=true")} else {tags = append(tags, "secure=false")}if serviceInstance.GetMetadata() != nil {var tags []stringfor key, value := range serviceInstance.GetMetadata() {tags = append(tags, key+"="+value)}registration.Tags = tags}registration.Tags = tagsregistration.Address = serviceInstance.GetHost()// 增加consul健康檢查回調函數check := new(api.AgentServiceCheck)schema := "http"if serviceInstance.IsSecure() {schema = "https"}check.HTTP = fmt.Sprintf("%s://%s:%d/actuator/health", schema, registration.Address, registration.Port)check.Timeout = "5s"check.Interval = "5s"check.DeregisterCriticalServiceAfter = "20s" // 故障檢查失敗30s后 consul自動將注冊服務刪除registration.Check = check// 注冊服務到consulerr := c.client.Agent().ServiceRegister(registration)if err != nil {fmt.Println(err)return false}//初始化服務實例緩存結構//若未初始化，服務ID-實例ID-實例if c.serviceInstances == nil {c.serviceInstances = map[string]map[string]cloud.ServiceInstance{}}//獲取特定服務的實例集合//從外層map中查詢該服務ID對應的內層mapservices := c.serviceInstances[serviceInstance.GetServiceId()]//初始化空實例集合//處理首次注冊情況，創建新的內層map，用處存儲該服務的實例集合if services == nil {services = map[string]cloud.ServiceInstance{}}//添加當前實例到集合services[serviceInstance.GetInstanceId()] = serviceInstance//更新外層緩存	//確保外層map中服務ID對應內層map是最新版本	c.serviceInstances[serviceInstance.GetServiceId()] = services//記錄當前實例c.localServiceInstance = serviceInstancereturn true
}// deregister a service
func (c consulServiceRegistry) Deregister() {//檢查服務實例緩存是否初始化if c.serviceInstances == nil {return}//從緩存中獲取當前服務ID對應的實例集合（實例ID->實例對象）services := c.serviceInstances[c.localServiceInstance.GetServiceId()]//檢查實例集合是否存在if services == nil {return}//從本地緩存移除當前實例delete(services, c.localServiceInstance.GetInstanceId())//清空服務記錄if len(services) == 0 {delete(c.serviceInstances, c.localServiceInstance.GetServiceId())}//從Consul注銷服務_ = c.client.Agent().ServiceDeregister(c.localServiceInstance.GetInstanceId())//重置當前實例記錄c.localServiceInstance = nil
}// new a consulServiceRegistry instance
// token is optional
func NewConsulServiceRegistry(host string, port int, token string) (*consulServiceRegistry, error) {if len(host) < 3 {return nil, errors.New("check host")}if port <= 0 || port > 65535 {return nil, errors.New("check port, port should between 1 and 65535")}config := api.DefaultConfig()config.Address = host + ":" + strconv.Itoa(port)config.Token = tokenclient, err := api.NewClient(config)if err != nil {return nil, err}return &consulServiceRegistry{client: *client}, nil
}

測試用例：

func TestConsulServiceRegistry(t *testing.T) {//初始化Consul注冊中心客戶端host := "127.0.0.1"port := 8500registryDiscoveryClient, _ := extension.NewConsulServiceRegistry(host, port, "")//獲取本地IP地址ip, err := util.GetLocalIP()if err != nil {t.Error(err)}//創建服務實例信息serviceInstanceInfo, _ := cloud.NewDefaultServiceInstance("go-user-server", "", 8090,false, map[string]string{"user":"zyn"}, "")//注冊服務實例
registryDiscoveryClient.Register(serviceInstanceInfo)r := gin.Default()// 健康檢測接口，其實只要是 200 就認為成功了r.GET("/actuator/health", func(c *gin.Context) {c.JSON(200, gin.H{"message": "pong",})})err = r.Run(":8090")if err != nil{registryDiscoveryClient.Deregister()}
}

3、服務發現

• 獲取所有的服務列表
• 獲取指定的服務的所有實例信息

接口定義：

type DiscoveryClient interface {/*** Gets all ServiceInstances associated with a particular serviceId.* @param serviceId The serviceId to query.* @return A List of ServiceInstance.*/GetInstances(serviceId string) ([]cloud.ServiceInstance, error)/*** @return All known service IDs.*/GetServices() ([]string, error)
}

具體實現：

type consulServiceRegistry struct {serviceInstances     map[string]map[string]cloud.ServiceInstanceclient               api.ClientlocalServiceInstance cloud.ServiceInstance
}func (c consulServiceRegistry) GetInstances(serviceId string) ([]cloud.ServiceInstance, error) {//查詢指定服務catalogService, _, _ := c.client.Catalog().Service(serviceId, "", nil)//若查詢到服務實例if len(catalogService) > 0 {//轉換Consul數據到標準格式result := make([]cloud.ServiceInstance, len(catalogService))for index, sever := range catalogService {s := cloud.DefaultServiceInstance{InstanceId: sever.ServiceID,ServiceId:  sever.ServiceName,Host:       sever.Address,Port:       sever.ServicePort,Metadata:   sever.ServiceMeta,}result[index] = s}return result, nil}return nil, nil
}
//返回服務名稱列表
func (c consulServiceRegistry) GetServices() ([]string, error) {//查詢所有服務services, _, _ := c.client.Catalog().Services(nil)result := make([]string, unsafe.Sizeof(services))index := 0for serviceName, _ := range services {result[index] = serviceNameindex++}return result, nil
}// new a consulServiceRegistry instance
// token is optional
func NewConsulServiceRegistry(host string, port int, token string) (*consulServiceRegistry, error) {if len(host) < 3 {return nil, errors.New("check host")}if port <= 0 || port > 65535 {return nil, errors.New("check port, port should between 1 and 65535")}config := api.DefaultConfig()config.Address = host + ":" + strconv.Itoa(port)config.Token = tokenclient, err := api.NewClient(config)if err != nil {return nil, err}return &consulServiceRegistry{client: *client}, nil
}

測試用例：

func TestConsulServiceDiscovery(t *testing.T) {host := "127.0.0.1"port := 8500token := ""registryDiscoveryClient, err := extension.NewConsulServiceRegistry(host, port, token)if err != nil {panic(err)}t.Log(registryDiscoveryClient.GetServices())t.Log(registryDiscoveryClient.GetInstances("go-user-server"))
}

結果：

consul_service_registry_test.go:57: [consul go-user-server      ] <nil>consul_service_registry_test.go:59: [{go-user-server-1602590661-56179 go-user-server 127.0.0.1 8090 false map[user:zyn]}] <nil>