一、概要

Ocelot是.Net Core下一个开源API网关；Ocelot主要目标是在.NET在微服务或面向服务架构中提供统一的入口服务，

Ocelot拿到HttpRequest对象到管道后，先创建HttpRequestMessage对象，该对象用于向下游服务发出请求。再将HttpResponseMessage映射到HttpResponse对象上，并返回给客户端。。

主要功能：统一入口、认证、鉴权、限流熔断、内置了负载均衡等等

二、单网关QuickStart

2.1 API网关

新建.Net Core 2.0 webapi项目:Practice.ApiGetway

添加Ocelot的Nuget包引用到该项目：Install-Package Ocelot

修改Startup.cs：

public class Startup

    {

        public Startup(IConfiguration configuration)

        {

            Configuration = configuration;

        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.

        public void ConfigureServices(IServiceCollection services)

        {

            services.AddMvc();

            services.AddOcelot(new ConfigurationBuilder().AddJsonFile("ocelot_config.json").Build());

        }

        // 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().Wait();

            app.UseMvc();

        }

    }

修改Program.cs：

public class Program

    {

        public static void Main(string[] args)

        {

            BuildWebHost(args).Run();

        }

        public static IWebHost BuildWebHost(string[] args) =>

            WebHost.CreateDefaultBuilder(args)

                .UseKestrel()

                .UseUrls("http://*:5000")

                .UseContentRoot(Directory.GetCurrentDirectory())

                .UseStartup<Startup>()

                .Build();

    }

添加一个json文件ocelot_config.json，设置属性：始终复制

{

  "ReRoutes": [

    {

      "DownstreamPathTemplate": "/api/users",

      "DownstreamScheme": "http",

      "DownstreamHostAndPorts": [

        {

          "Host": "localhost",

          "Port":

        }

      ],

      "UpstreamPathTemplate": "/users/values",

      "UpstreamHttpMethod": [ "Get" ],

      "QoSOptions": {

        "ExceptionsAllowedBeforeBreaking": ,

        "DurationOfBreak": ,

        "TimeoutValue":

      }

    },

    {

      "DownstreamPathTemplate": "/api/news",

      "DownstreamScheme": "http",

      "DownstreamHostAndPorts": [

        {

          "Host": "localhost",

          "Port":

        }

      ],

      "UpstreamPathTemplate": "/news/values",

      "UpstreamHttpMethod": [ "Get" ],

      "QoSOptions": {

        "ExceptionsAllowedBeforeBreaking": ,

        "DurationOfBreak": ,

        "TimeoutValue":

      }

    }

  ],

  "GlobalConfiguration": {

    //"BaseUrl": "https://api.mybusiness.com"

  }

}