服务注册与发现Consul

下载 https://www.consul.io/

windows 下就一个文件，直接运行

#开发模式，就不用配其他参数了

consul.exe agent -dev

#

consul.exe agent -server -data-dir=d:\consul\data\ -ui

 

 

c# 服务端

public static void RegisterConsul(this IConfiguration configuration)
{
   var host = Evnironment.MachineName;
   var port = int.Parse(configuration["port"]); //从配置中取端口参数
   var client = new ConsulClient(c=>c.Address=new Uri("http://127.0.0.1:8500"));
   var registration = new AgentServiceRegistration()
   {
       Check = new AgentServiceCheck(){
         HTTP = $"http://{host}:{port}/Api/Health",
         Interval = TimeSpan.FromSeconds(1),
         DeregisterCriticalServiceAfter = TimeSpan.FromSeconds(10),
         Timeout = TimeSpan.FromSeconds(5)
       },
       Address = host,
       Port = port,
       ID = host+":"+port,
       Name = "TestService", 
       };
   client.Agent.ServiceRegister(registration);
}

运行服务 dotnet Service.dll --urls=http://*:7777 --port=7777

这里有两个地方要注意：

1、服务的ID一定要用唯一的，否则每次启动都注册一个服务，健康检查又能通过，后面就麻烦了

2、还是服务失效的问题，consul不会立即发现，需要客户端做容灾处理

 

客户端

        protected string InvokeApi(string url)
        {
            var client = new ConsulClient(c=>c.Address=new Uri("http://127.0.0.1:8500"));
            var result = client.Agent.Services().Result;
            if (result.StatusCode != HttpStatusCode.OK)
                throw new ApplicationException("Consul return:" + result.StatusCode);
            var services = result.Response.Values.ToArray();
            var nIndex = (new Random()).Next() % services.Length;
            var server = services[nIndex];
            using var httpClient = new HttpClient();
            Console.WriteLine(url);
            var resp = httpClient.GetAsync($"http://{server.Address}:{server.Port}{url}").Result;
            if (!resp.IsSuccessStatusCode)
                throw new ApplicationException("http request error:" + resp.StatusCode.ToString());
            return resp.Content.ReadAsStringAsync().Result;
        }

这里需要特别注意的就是

1、请求consul会有异常，请求回来的服务端也可能是已经失效了的

2、需要自己做负载均衡