.NET 8 + Ocelot + Consul 实现代理网关、服务发现

.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IP
       Port = 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