.NET 8 + Ocelot + Consul 实现代理网关、服务发现

本文环境：.NET 8 + Ocelot 23.4.2 + Consul 1.7.14.6

1 实现网关

1. 分别创建3个WebApi工程：OcelotGw、TestGwAService、TestGwBService；
2. 在OcelotGw工程中安装Ocelot包：Install-Package Ocelot
3. 添加JSON配置文件或直接在appsettings.json文件中添加配置；
   1. 配置内容：

   {"Routes": [{"DownstreamPathTemplate": "/api/{url}","DownstreamScheme": "https","DownstreamHostAndPorts": [{"Host": "localhost","Port": 5001}],"UpstreamPathTemplate": "/A/{url}","UpstreamHttpMethod": [ "Get" ]},{"DownstreamPathTemplate": "/api/{url}","DownstreamScheme": "https","DownstreamHostAndPorts": [{"Host": "localhost","Port": 5002}],"UpstreamPathTemplate": "/B/{url}","UpstreamHttpMethod": [ "Get" ]},{"DownstreamPathTemplate": "/todos/{id}","DownstreamScheme": "https","DownstreamHostAndPorts": [{"Host": "jsonplaceholder.typicode.com","Port": 443}],"UpstreamPathTemplate": "/todos/{id}","UpstreamHttpMethod": [ "Get" ]}],"GlobalConfiguration": {"BaseUrl": "https://localhost:5000/"}
   }
   

4. 在测试服务中分别添加HelloController

   [Route("api/[controller]")]
   [ApiController]
   public class HelloController : ControllerBase
   {[HttpGet]public IActionResult Get(){return Ok("Hello from Service A!");}
   }
   

5. 同时启动三个工程，并访问https://localhost:5000/B/Hello和https://localhost:5000/B/Hello测试。

2 服务发现

下面使用服务发现完成ServiceA的配置；

1. 下载Consul：Install Consul
2. 运行Consul，启动命令：consul.exe agent -dev；
3. 修改ServiceA的Ocelot配置：

   {"UseServiceDiscovery": true,"DownstreamPathTemplate": "/api/{url}","DownstreamScheme": "http","ServiceName": "ServiceA","UpstreamPathTemplate": "/A/{url}","UpstreamHttpMethod": [ "Get" ]
   }
   

4. 在ServiceA中添加健康监测接口：

   using Microsoft.AspNetCore.Mvc;
   namespace Hearth.TestGwAService.Controllers
   {[Route("[controller]/[action]")][ApiController]public class HealthController : ControllerBase{[HttpGet("/healthCheck")]public IActionResult Check() => Ok("ok");}
   }
   

5. 在ServiceA的Program中进行代理服务注册：

   var consulClient = new ConsulClient(x =>
   {// consul 服务地址x.Address = new Uri("http://localhost:8500");
   });
   var registration = new AgentServiceRegistration()
   {ID = Guid.NewGuid().ToString(),Name = "ServiceA",// 服务名Address = "localhost", // 服务绑定IPPort = 5001, // 服务绑定端口Check = 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HTTP = "http://localhost:5001/healthCheck",//健康检查地址Timeout = TimeSpan.FromSeconds(5)}
   };
   // 服务注册
   consulClient.Agent.ServiceRegister(registration).Wait();
   var app = builder.Build();
   // 应用程序终止时，服务取消注册
   app.Lifetime.ApplicationStopping.Register(() =>
   {consulClient.Agent.ServiceDeregister(registration.ID).Wait();
   });
   

3 一些问题

1. 在Ocelot配置文件中，旧版本可能用的是ReRoutes，新版本中应该是Routes；
2. 注意DownstreamScheme，如果使用ssl应为https；
3. 在开发环境使用Consul服务发现时，需要注意是否使用SSL验证，无效的证书会导致502 Bad Gateway；
4. 官方文档：ocelot.readthedocs.io