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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 service
func (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 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 = 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 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 = 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/…