关于golang:Go-Go-使用-consul-做服务发现

系列文章目录

@TOC

前言

后面一章讲了微服务的一些长处和毛病，那如何做到

一、指标

二、应用步骤

1. 装置 consul

咱们能够间接应用官网提供的二进制文件来进行装置部署，其官网地址为 https://www.consul.io/downloads

下载后为可执行文件，在咱们开发试验过程中，能够间接应用 consul agent -dev 命令来启动一个单节点的 consul

在启动的打印日志中能够看到 agent: Started HTTP server on 127.0.0.1:8500 (tcp), 咱们能够在浏览器间接拜访 127.0.0.1:8500 即可看到如下

这里咱们的 consul 就启动胜利了

2. 服务注册

在网络编程中，个别会提供我的项目的 IP、PORT、PROTOCOL，在服务治理中，咱们还须要晓得对应的服务名、实例名以及一些自定义的扩大信息

在这里应用 ServiceInstance 接口来规定注册服务时必须的一些信息，同时用 DefaultServiceInstance 实现

type ServiceInstance interface {    // return The unique instance ID as registered.    GetInstanceId() string    // return The service ID as registered.    GetServiceId() string    // return The hostname of the registered service instance.    GetHost() string    // return The port of the registered service instance.    GetPort() int    // return Whether the port of the registered service instance uses HTTPS.    IsSecure() bool    // return The key / value pair metadata associated with the service instance.    GetMetadata() map[string]string}type DefaultServiceInstance struct {    InstanceId string    ServiceId  string    Host       string    Port       int    Secure     bool    Metadata   map[string]string}func NewDefaultServiceInstance(serviceId string, host string, port int, secure bool,    metadata map[string]string, instanceId string) (*DefaultServiceInstance, error) {    // 如果没有传入 IP 则获取一下，这个办法在多网卡的状况下，并不好用    if len(host) == 0 {        localIP, err := util.GetLocalIP()        if err != nil {            return nil, err        }        host = localIP    }    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}

定义接口

在下面规定了须要注册的服务的必要信息，上面定义下服务注册和剔除的办法

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

具体实现

因为 consul 提供了 http 接口来对consul 进行操作，咱们也能够应用 http 申请形式进行注册和剔除操作，具体 http 接口文档见 https://www.consul.io/api-docs, consul 默认提供了go 语言的实现，这里间接应用 github.com/hashicorp/consul/api

import (    "errors"    "fmt"    "github.com/hashicorp/consul/api"    "strconv"    "unsafe")type consulServiceRegistry struct {    serviceInstances     map[string]map[string]cloud.ServiceInstance    client               api.Client    localServiceInstance cloud.ServiceInstance}func (c consulServiceRegistry) Register(serviceInstance cloud.ServiceInstance) bool {    // 创立注册到consul的服务到    registration := new(api.AgentServiceRegistration)    registration.ID = serviceInstance.GetInstanceId()    registration.Name = serviceInstance.GetServiceId()    registration.Port = serviceInstance.GetPort()    var tags []string    if serviceInstance.IsSecure() {        tags = append(tags, "secure=true")    } else {        tags = append(tags, "secure=false")    }    if serviceInstance.GetMetadata() != nil {        var tags []string        for key, value := range serviceInstance.GetMetadata() {            tags = append(tags, key+"="+value)        }        registration.Tags = tags    }    registration.Tags = tags    registration.Address = serviceInstance.GetHost()    // 减少consul健康检查回调函数    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" // 故障查看失败30s后 consul主动将注册服务删除    registration.Check = check    // 注册服务到consul    err := c.client.Agent().ServiceRegister(registration)    if err != nil {        fmt.Println(err)        return false    }    if c.serviceInstances == nil {        c.serviceInstances = map[string]map[string]cloud.ServiceInstance{}    }    services := c.serviceInstances[serviceInstance.GetServiceId()]    if services == nil {        services = map[string]cloud.ServiceInstance{}    }    services[serviceInstance.GetInstanceId()] = serviceInstance    c.serviceInstances[serviceInstance.GetServiceId()] = services    c.localServiceInstance = serviceInstance    return true}// deregister a servicefunc (c consulServiceRegistry) Deregister() {    if c.serviceInstances == nil {        return    }    services := c.serviceInstances[c.localServiceInstance.GetServiceId()]    if services == nil {        return    }    delete(services, c.localServiceInstance.GetInstanceId())    if len(services) == 0 {        delete(c.serviceInstances, c.localServiceInstance.GetServiceId())    }    _ = c.client.Agent().ServiceDeregister(c.localServiceInstance.GetInstanceId())    c.localServiceInstance = nil}// new a consulServiceRegistry instance// token is optionalfunc 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 = token    client, err := api.NewClient(config)    if err != nil {        return nil, err    }    return &consulServiceRegistry{client: *client}, nil}

测试用例

注册服务的代码根本实现，来测试一下

func TestConsulServiceRegistry(t *testing.T) {    host := "127.0.0.1"    port := 8500    registryDiscoveryClient, _ := extension.NewConsulServiceRegistry(host, port, "")    ip, err := util.GetLocalIP()    if err != nil {        t.Error(err)    }        serviceInstanceInfo, _ := cloud.NewDefaultServiceInstance("go-user-server", "", 8090,        false, map[string]string{"user":"zyn"}, "")    registryDiscoveryClient.Register(serviceInstanceInfo)    r := gin.Default()    // 衰弱检测接口，其实只有是 200 就认为胜利了    r.GET("/actuator/health", func(c *gin.Context) {        c.JSON(200, gin.H{            "message": "pong",        })    })    err = r.Run(":8090")    if err != nil{        registryDiscoveryClient.Deregister()    }}

如果胜利，则会在 consul 看到 go-user-server 这个服务

3. 服务发现

在服务发现中，个别会须要两个办法

获取所有的服务列表
获取指定的服务的所有实例信息

接口定义

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)}

具体实现

来实现一下

type consulServiceRegistry struct {    serviceInstances     map[string]map[string]cloud.ServiceInstance    client               api.Client    localServiceInstance cloud.ServiceInstance}func (c consulServiceRegistry) GetInstances(serviceId string) ([]cloud.ServiceInstance, error) {    catalogService, _, _ := c.client.Catalog().Service(serviceId, "", nil)    if len(catalogService) > 0 {        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}func (c consulServiceRegistry) GetServices() ([]string, error) {    services, _, _ := c.client.Catalog().Services(nil)    result := make([]string, unsafe.Sizeof(services))    index := 0    for serviceName, _ := range services {        result[index] = serviceName        index++    }    return result, nil}// new a consulServiceRegistry instance// token is optionalfunc 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 = token    client, err := api.NewClient(config)    if err != nil {        return nil, err    }    return &consulServiceRegistry{client: *client}, nil}

测试用例

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

后果

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>

总结

通过应用 consul api 咱们能够简略的实现基于 consul 的服务发现，在通过联合 http rpc 就可简略的实现服务的调用，上面一章来简略讲下 go 如何发动 http 申请，为咱们做 rpc 做个铺垫

具体代码见 https://github.com/zhangyunan...

参考

https://www.consul.io/api-docs
https://github.com/hashicorp/...