web api gateway of .net5+ocelot+consul

.net web api 网关入门

1. dotNet 5
2. ocelot + consul

ocelot 增加consul服务发现网关访问提示404问题

ocelot 及 consul 配置经反复对比未发现问题，去除服务发现，恢复下游列表定义的方式网关是可用的（列表方式虽然可用，但负载均衡在站点服务不可用时仍然发送请求过去了，没有达到自动切换的效果），推断问题在ocelot注入端。

1. 原注入ocelot方式

    services
         .AddOcelot(new ConfigurationBuilder()
              .AddJsonFile("ocelot.json", optional: false, reloadOnChange: true)
              .Build())
          .AddConsul();

2. 需调整为

     services
          .AddOcelot()
          .AddConsul();

ocelot.json 放在 program中注入：

    Host.CreateDefaultBuilder(args)
        .ConfigureAppConfiguration((hostingContext, config) =>
        {
            config.SetBasePath(hostingContext.HostingEnvironment.ContentRootPath)
            .AddJsonFile("ocelot.json")
            .AddEnvironmentVariables();
        })
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup();
        });

Then runs perfect as expected.

ocelot & consul nuget package

1. Ocelot
2. Ocelot.Provider.Consul

ocelot config

{
  "Routes": [
    {
      "DownstreamPathTemplate": "/api/{controller}/{action}",
      "UpstreamPathTemplate": "/yourPrefix/{controller}/{action}",
      "UpstreamHttpMethod": [
        "Get",
        "POST"
      ],
      "DownstreamScheme": "http",
      "UseServiceDiscovery": true,
      "ReRouteIsCaseSensitive": false,
      "ServiceName": "YourServiceName",
      "LoadBalancerOptions": {
        "Type": "RoundRobin"
      }
    },

    {
      "DownstreamPathTemplate": "/yourPrefix/{everything}",
      "UpstreamPathTemplate": "/yourPrefix/{everything}",
      "UpstreamHttpMethod": [
        "Get",
        "POST"
      ],
      "DownstreamScheme": "http",
      "UseServiceDiscovery": true,
      "ReRouteIsCaseSensitive": false,
      "ServiceName": "YourServiceName",
      "LoadBalancerOptions": {
        "Type": "RoundRobin"
      }
    }
  ],
  "GlobalConfiguration": { 
    "ServiceDiscoveryProvider": {
      "Scheme": "http",
      "Host": "localhost",
      "Port": 8500,
      "Type": "Consul"
    }
  }
}

consul services config

{
  "services": [
    {
      "id": "webapi1",
      "name": "YourServiceName",
      "tags": [ "WebApi" ],
      "address": "127.0.0.1",
      "port": 51012,
      "checks": [
        {
          "id": "AbcCheck1",
          "name": "Abc_Check",
          "http": "http://127.0.0.1:51012/weatherforecast",
          "interval": "10s",
          "tls_skip_verify": false,
          "method": "GET",
          "timeout": "1s"
        }
      ]
    },

    {
      "id": "webapi2",
      "name": "YourServiceName",
      "tags": [ "WebApi" ],
      "address": "127.0.0.1",
      "port": 51013,
      "checks": [
        {
          "id": "AbcCheck2",
          "name": "Abc1_Check",
          "http": "http://127.0.0.1:51013/weatherforecast",
          "interval": "10s",
          "tls_skip_verify": false,
          "method": "GET",
          "timeout": "1s"
        }
      ]
    }
  ]
}

Consul, Important: Run Consul as Windows Service

1. 下载安装consul https://www.consul.io/.
   ps: 下载很慢，超过1个小时

2. sc 创建服务（创建后到服务中更改启动方式为“自动(延迟启动)”）

sc.exe create "Consul" binPath= "D:Consulconsul.exe agent -server -ui -bootstrap-expect=1 -data-dir=D:Consul -node=consulNode1 -client=0.0.0.0 -bind=YourLocalIP -datacenter=dc1 -config-dir=D:ConsulconsulServices.json" start= auto

注:(1)bootstrap-expect=1, windows 单机
(2)不需要“&”带入命令行，否则windows service 启动异常。
(3)延迟自动启动，该服务不能在系统重启过程启动（可能和consul.exe系统启动过程未识别到有关）

Postman 测试

1. 下游服务全部可用时，可以轮流发送。
2. 下游服务部分不可用时，仍然可以全部发送到可用的服务（不加consul时，ocelot就是服务不可用也发送过去了）

.net 5 ocelot consul web api gateway 入门总结，欢迎转载:https://blog.csdn.net/wenlaishiwo/article/details/111830852 参考资源

(1) https://www.cnblogs.com/zhaobingwang/p/12424708.html
(2) https://blog.csdn.net/anqi4868/article/details/101800352
(3) https://www.cnblogs.com/shanyou/p/6286207.html
(4) https://learn.hashicorp.com/tutorials/consul/windows-agent
(5) https://ocelot.readthedocs.io/en/latest/index.html