前言上一篇【.Net Core微服务入门全纪录（一）——项目搭建】讲到要做到服务的灵活伸缩，那么需要有一种机制来实现它，这个机制就是服务注册与发现。当然这也并不是必要的，如果你的服务实例很少，并且很稳定，那么就没有必要使用服务注册与发现。 服务注册与发现
有了服务注册与发现，客户端就不用再去配置各个服务实例的地址，改为从注册中心统一获取。
常见注册中心有 Consul、ZooKeeper、etcd、Eureka。 ConsulConsul官网：https://www./
服务注册
ConsulHelper.cs： public static class ConsulHelper
{
/// <summary>
/// 服务注册到consul
/// </summary>
/// <param name="app"></param>
/// <param name="lifetime"></param>
public static IApplicationBuilder RegisterConsul(this IApplicationBuilder app, IConfiguration configuration, IHostApplicationLifetime lifetime)
{
var consulClient = new ConsulClient(c =>
{
//consul地址
c.Address = new Uri(configuration["ConsulSetting:ConsulAddress"]);
});
var registration = new AgentServiceRegistration()
{
ID = Guid.NewGuid().ToString(),//服务实例唯一标识
Name = configuration["ConsulSetting:ServiceName"],//服务名
Address = configuration["ConsulSetting:ServiceIP"], //服务IP
Port = int.Parse(configuration["ConsulSetting:ServicePort"]),//服务端口 因为要运行多个实例，端口不能在appsettings.json里配置，在docker容器运行时传入
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://{configuration["ConsulSetting:ServiceIP"]}:{configuration["ConsulSetting:ServicePort"]}{configuration["ConsulSetting:ServiceHealthCheck"]}",//健康检查地址
Timeout = TimeSpan.FromSeconds(5)//超时时间
}
};
//服务注册
consulClient.Agent.ServiceRegister(registration).Wait();
//应用程序终止时，取消注册
lifetime.ApplicationStopping.Register(() =>
{
consulClient.Agent.ServiceDeregister(registration.ID).Wait();
});
return app;
}
}appsettings.json： {
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Information"
}
},
"AllowedHosts": "*",
"ConsulSetting": {
"ServiceName": "OrderService",
"ServiceIP": "localhost",
"ServiceHealthCheck": "/healthcheck",
"ConsulAddress": "http://host.ernal:8500"//注意，docker容器内部无法使用localhost访问宿主机器，如果是控制台启动的话就用localhost
}
}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.AddControllers();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IHostApplicationLifetime lifetime)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
//服务注册
app.RegisterConsul(Configuration, lifetime);
}
}OrdersController.cs： [Route("[controller]")]
[ApiController]
public class OrdersController : ControllerBase
{
private readonly ILogger<OrdersController> _logger;
private readonly IConfiguration _configuration;
public OrdersController(ILogger<OrdersController> logger, IConfiguration configuration)
{
_logger = logger;
_configuration = configuration;
}
[HttpGet]
public IActionResult Get()
{
string result = $"【订单服务】{DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")}——" +
$"{Request.HttpContext.Connection.LocalIpAddress}:{_configuration["ConsulSetting:ServicePort"]}";
return Ok(result);
}
}HealthCheckController.cs： [Route("[controller]")]
[ApiController]
public class HealthCheckController : ControllerBase
{
/// <summary>
/// 健康检查接口
/// </summary>
/// <returns></returns>
[HttpGet]
public IActionResult Get()
{
return Ok();
}
}至此就完成了服务注册，取消注册，健康检查等功能的代码编写。
运行服务继续在docker中运行服务实例，不习惯docker的话用控制台启动也行。--ConsulSetting:ServicePort参数就是传入容器的端口信息。 docker build -t orderapi:1.0 -f ./Order.API/Dockerfile . docker run -d -p 9060:80 --name orderservice orderapi:1.0 --ConsulSetting:ServicePort="9060" docker run -d -p 9061:80 --name orderservice1 orderapi:1.0 --ConsulSetting:ServicePort="9061" docker run -d -p 9062:80 --name orderservice2 orderapi:1.0 --ConsulSetting:ServicePort="9062" docker build -t productapi:1.0 -f ./Product.API/Dockerfile . docker run -d -p 9050:80 --name productservice productapi:1.0 --ConsulSetting:ServicePort="9050" docker run -d -p 9051:80 --name productservice1 productapi:1.0 --ConsulSetting:ServicePort="9051" docker run -d -p 9052:80 --name productservice2 productapi:1.0 --ConsulSetting:ServicePort="9052"
至此，6个服务器实例都已运行，并且成功注册到Consul。 随便停止2个服务：
//应用程序终止时，取消注册
lifetime.ApplicationStopping.Register(() =>
{
consulClient.Agent.ServiceDeregister(registration.ID).Wait();
});当然程序发生异常，健康检查不能正确响应的话，Consul也会移除，有一点区别。 那么注册，发现，健康检查功能都完成了，下一步就该考虑客户端如何拿到这些服务实例的地址了。 |
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