.Net Core 商城微服务项目系列（二）：使用Ocelot + Consul构建具备服务注册和发现功能的网关 - 好文

1.服务注册

在上一篇的鉴权和登录服务中分别通过NuGet引用Consul这个包，同时新增AppBuilderExtensions类：
public static class AppBuilderExtensions { public static IApplicationBuilder
RegisterConsul(this IApplicationBuilder app,IApplicationLifetime
lifetime,ServiceEntity serviceEntity) {var consulClient = new ConsulClient(x =>
x.Address =new Uri($"http://{serviceEntity.ConsulIP}:{serviceEntity.ConsulPort}"
));//请求注册的Consul地址 var httpCheck = new AgentServiceCheck() {
DeregisterCriticalServiceAfter=TimeSpan.FromSeconds(5),//服务启动多久后注册
Interval=TimeSpan.FromSeconds(10),//健康检查时间间隔，或者成为心跳间隔 HTTP=$"
http://{serviceEntity.IP}:{serviceEntity.Port}/api/health",//健康检查地址
Timeout=TimeSpan.FromSeconds(5) }; //Register service with consul var
registration =new AgentServiceRegistration() { Checks = new[] {httpCheck}, ID=
Guid.NewGuid().ToString(), Name=serviceEntity.ServiceName, Address=
serviceEntity.IP, Port=serviceEntity.Port, Tags = new[] { $"
urlprefix-/{serviceEntity.ServiceName}"} //
添加urlprefix-/servicename格式的tag标签，以便Fabio识别 };
consulClient.Agent.ServiceRegister(registration).Wait();//
服务启动时注册，内部实现其实就是使用Consul API进行注册（HttpClient发起)
lifetime.ApplicationStopping.Register(() => {
consulClient.Agent.ServiceDeregister(registration.ID).Wait();//服务停止时取消注册 });
return app; } } public class ServiceEntity { public string IP { get; set; }
public int Port { get; set; } public string ServiceName { get; set; } public
string ConsulIP { get; set; } public int ConsulPort { get; set; } }
通过这个类可以提供服务注册的基本参数。

修改Startup启动项中的Configure方法：
public void Configure(IApplicationBuilder app, IHostingEnvironment env,
IApplicationLifetime lifetime) {if (env.IsDevelopment()) {
app.UseDeveloperExceptionPage(); }#region Consul 服务注册 ServiceEntity
serviceEntity= new ServiceEntity { IP = "127.0.0.1", //服务运行地址 Port =
Convert.ToInt32(Configuration["Consul:ServicePort"]), //服务运行端口 ServiceName =
Configuration["Consul:Name"], //服务标识,Ocelot中会用到 ConsulIP = Configuration["
Consul:IP"], //Consul运行地址 ConsulPort = Convert.ToInt32(Configuration["
Consul:Port"]) //Consul运行端口（默认8500） }; app.RegisterConsul(lifetime,
serviceEntity);#endregion app.UseIdentityServer(); //app.UseAuthentication();
app.UseStaticFiles(); app.UseMvcWithDefaultRoute(); }
看下配置文件需要新增的东西：
{ "Service": { "Name": "MI.Service", "Port": "7001", "DocName": "Account
Service", "Version": "v1", "Title": "Account Service API" }, "Identity": { "IP":
"localhost", "Port": "7000", "Scheme": "Bearer" }, "ConnectionStrings": { "
SqlConnection": "server=.;uid=sa;pwd=sa;database=MI" }, "Consul": { "Name":
"MI.Service.Account", "ServiceProt": "7001", "IP": "localhost", "Port": "8500" }
}
蓝色标识的Consul部分是我们这里需要用到的，这里我把项目名称当作服务注册标识。

然后还需要为两个服务添加两个方法，一个是用来做健康检查的，一个是用来测试的：
[Route("api/Health")] public class HealthController : Controller { [HttpGet]
public IActionResult Get() => Ok("ok"); } public class MiUserController :
Controller {public MIContext _context; public MiUserController(MIContext
_context) {this._context = _context; } public string Index() { return "
Successful"; } 。。。。。。 }

通过“consul agent -dev”命令运行Consul，访问127.0.0.1：8500我们可以看到Consul的UI界面：

这里可以看到我们已经注册的两个服务。

2.服务发现

新建API项目MI.Ocelot，通过NuGet引用Ocelot和Ocelot.Provider.Consul两个包，并修改启动项注册Ocelot和Consul：
public void ConfigureServices(IServiceCollection services) { //
services.AddMvc(); services.AddOcelot(Configuration) .AddConsul(); } // This
method gets called by the runtime. Use this method to configure the HTTP
request pipeline. public void Configure(IApplicationBuilder app,
IHostingEnvironment env) {if (env.IsDevelopment()) {
app.UseDeveloperExceptionPage(); } app.UseOcelot();//app.UseMvc(); }
然后添加配置文件consul.json:
{ "ReRoutes": [ { "UseServiceDiscovery": true, //启用服务发现 "DownstreamPathTemplate
": "/Account/{url}", //下游转发路由 "DownstreamScheme": "http", //标识头 "ServiceName": "
MI.Service.Account", //服务注册标识 "LoadBalancer": "RoundRobin", //服务均衡：轮询 "
UpstreamPathTemplate": "/Account/{url}", //上游请求路由 "UpstreamHttpMethod": [ "Get",
"Post" ], //请求的方法类型 "ReRoutesCaseSensitive": false //不区分大小写 }, { "
UseServiceDiscovery": true, "DownstreamPathTemplate": "/Identity/{url}", "
DownstreamScheme": "http", "ServiceName": "MI.Service.IdentityServer", "
LoadBalancer": "RoundRobin", "UpstreamPathTemplate": "/Identity/{url}", "
UpstreamHttpMethod": [ "Get", "Post" ], "ReRoutesCaseSensitive": false } ], "
GlobalConfiguration": { //"BaseUrl": "http://localhost:7003", "
ServiceDiscoveryProvider": { "Host": "127.0.0.1", // Consul Service IP "Port":
8500, // Consul Service Port "Type": "PollConsul", "PollingInterval": 100 //
健康检查时间端 } } }
在Program中启用这个配置文件：
public static IWebHost BuildWebHost(string[] args) =>
WebHost.CreateDefaultBuilder(args) .UseStartup<Startup>()
.ConfigureAppConfiguration((hostingContext,builder)=> { builder.AddJsonFile("
consul.json"); }) .Build();

到此，网关配置完毕。现在我将网关项目MI.Gateway部署在7003端口，登录服务MI.Service.Account部署在7001端口，鉴权服务部署在7000端口，我会通过访问网关服务来请求登录服务：

这里的流程是这样的，Ocelot通过“/Account/MiUser/Index”匹配到了“/Account/{url}”这个路由，进而拿到了“MI.Service.Account”这个服务注册标识，然后通过Consul拿到了对应的地址，并转发了请求，同时返回结果。

到此，具备服务注册和发现的简单网关服务就搭建完毕了，后面有时间会继续优化，添加限流、熔断，同时身份验证会在Ocelot中进行，而不是再去访问单独的鉴权服务。

热门工具换一换