.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...

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 consulvar 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);#endregionapp.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：