C# HttpClient 如何使用 Consul 发现服务

编程入门行业动态更新时间:2024-10-08 01:30:06

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C# HttpClient 如何使用 Consul 发现服务

试用了Overt.Core.Grpc, 把 GRPC 的使用改造得像 WCF, 性能测试也非常不错, 非常推荐各位使用.
　　但已有项目大多是 http 请求, 改造成 GRPC 的话, 工作量比较大, 于是又找到了 Steeltoe.Discovery, 在 Startup 给 HttpClient 添加 DelegatingHandler, 动态改变请求urlc#教程中的 host 和 port, 将http请求指向consul 发现的服务实例, 这样就实现了服务的动态发现.
　　经过性能测试, Steeltoe.Discovery 只有 Overt.Core.Grpc 的20%, 非常难以接受, 于是自己实现了一套基于 consul 的服务发现工具. 嗯, 名字好难取啊, 暂定为 ConsulDiscovery.HttpClient 吧
　　功能很简单:

webapi 从json中读取配置信息 ConsulDiscoveryOptions;
如果自己是一个服务, 则将自己注册到consul中并设置健康检查Url;
ConsulDiscovery.HttpClient 内有一个consul client 定时刷新所有服务的url访问地址.
　　比较核心的两个类

using Consul;
using Microsoft.Extensions.Options;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;namespace ConsulDiscovery.HttpClient
{public class DiscoveryClient : IDisposable{private readonly ConsulDiscoveryOptions consulDiscoveryOptions;private readonly Timer timer;private readonly ConsulClient consulClient;private readonly string serviceIdInConsul;public Dictionary<string, List<string>> AllServices { get; private set; } = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);public DiscoveryClient(IOptions<ConsulDiscoveryOptions> options){consulDiscoveryOptions = options.Value;consulClient = new ConsulClient(x => x.Address = new Uri($"http://{consulDiscoveryOptions.ConsulServerSetting.IP}:{consulDiscoveryOptions.ConsulServerSetting.Port}"));timer = new Timer(Refresh);if (consulDiscoveryOptions.ServiceRegisterSetting != null){serviceIdInConsul = Guid.NewGuid().ToString();}}public void Start(){var checkErrorMsg = CheckParams();if (checkErrorMsg != null){throw new ArgumentException(checkErrorMsg);}RegisterToConsul();timer.Change(0, consulDiscoveryOptions.ConsulServerSetting.RefreshIntervalInMilliseconds);}public void Stop(){Dispose();}private string CheckParams(){if (string.IsNullOrWhiteSpace(consulDiscoveryOptions.ConsulServerSetting.IP)){return "Consul服务器地址 ConsulDiscoveryOptions.ConsulServerSetting.IP 不能为空";}if (consulDiscoveryOptions.ServiceRegisterSetting != null){var registerSetting = consulDiscoveryOptions.ServiceRegisterSetting;if (string.IsNullOrWhiteSpace(registerSetting.ServiceName)){return "服务名称 ConsulDiscoveryOptions.ServiceRegisterSetting.ServiceName 不能为空";}if (string.IsNullOrWhiteSpace(registerSetting.ServiceIP)){return "服务地址 ConsulDiscoveryOptions.ServiceRegisterSetting.ServiceIP 不能为空";}}return null;}private void RegisterToConsul(){if (string.IsNullOrEmpty(serviceIdInConsul)){return;}var registerSetting = consulDiscoveryOptions.ServiceRegisterSetting;var httpCheck = new AgentServiceCheck(){HTTP = $"{registerSetting.ServiceScheme}{Uri.SchemeDelimiter}{registerSetting.ServiceIP}:{registerSetting.ServicePort}/{registerSetting.HealthCheckRelativeUrl.TrimStart('/')}",Interval = TimeSpan.FromMilliseconds(registerSetting.HealthCheckIntervalInMilliseconds),Timeout = TimeSpan.FromMilliseconds(registerSetting.HealthCheckTimeOutInMilliseconds),DeregisterCriticalServiceAfter = TimeSpan.FromSeconds(10),};var registration = new AgentServiceRegistration(){ID = serviceIdInConsul,Name = registerSetting.ServiceName,Address = registerSetting.ServiceIP,Port = registerSetting.ServicePort,Check = httpCheck,Meta = new Dictionary<string, string>() { ["scheme"] = registerSetting.ServiceScheme },};consulClient.Agent.ServiceRegister(registration).Wait();}private void DeregisterFromConsul(){if (string.IsNullOrEmpty(serviceIdInConsul)){return;}try{consulClient.Agent.ServiceDeregister(serviceIdInConsul).Wait();}catch{ }}private void Refresh(object state){Dictionary<string, AgentService>.ValueCollection serversInConsul;try{serversInConsul = consulClient.Agent.Services().Result.Response.Values;}catch // (Exception ex){// 如果连接consul出错, 则不更新服务列表. 继续使用以前获取到的服务列表// 但是如果很长时间都不能连接consul, 服务列表里的一些实例已经不可用了, 还一直提供这样旧的列表也不合理, 所以要不要在这里实现 健康检查? 这样的话, 就得把检查地址变成不能设置的return;}// 1. 更新服务列表// 2. 如果这个程序提供了服务, 还要检测 服务Id 是否在服务列表里var tempServices = new Dictionary<string, HashSet<string>>();bool needReregisterToConsul = true;foreach (var service in serversInConsul){var serviceName = service.Service;if (!service.Meta.TryGetValue("scheme", out var serviceScheme)){serviceScheme = Uri.UriSchemeHttp;}var serviceHost = $"{serviceScheme}{Uri.SchemeDelimiter}{service.Address}:{service.Port}";if (!tempServices.TryGetValue(serviceName, out var serviceHosts)){serviceHosts = new HashSet<string>();tempServices[serviceName] = serviceHosts;}serviceHosts.Add(serviceHost);if (needReregisterToConsul && !string.IsNullOrEmpty(serviceIdInConsul) && serviceIdInConsul == service.ID){needReregisterToConsul = false;}}if (needReregisterToConsul){RegisterToConsul();}var tempAllServices = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);foreach (var item in tempServices){tempAllServices[item.Key] = item.Value.ToList();}AllServices = tempAllServices;}public void Dispose(){DeregisterFromConsul();consulClient.Dispose();timer.Dispose();}}
}

using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;namespace ConsulDiscovery.HttpClient
{public class DiscoveryHttpMessageHandler : DelegatingHandler{private static readonly Random random = new Random((int)DateTime.Now.Ticks);private readonly DiscoveryClient discoveryClient;public DiscoveryHttpMessageHandler(DiscoveryClient discoveryClient){this.discoveryClient = discoveryClient;}protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken){if (discoveryClient.AllServices.TryGetValue(request.RequestUri.Host, out var serviceHosts)){if (serviceHosts.Count > 0){var index = random.Next(serviceHosts.Count);request.RequestUri = new Uri(new Uri(serviceHosts[index]), request.RequestUri.PathAndQuery);}}return await base.SendAsync(request, cancellationToken).ConfigureAwait(false);}}
}

使用方法

为了简单, 我为新建的WebApi 增加了一个 HelloController, 提供 SayHelloService 服务, 并把自己注册到Consul.

当我们访问这个WebApi的 /WeatherForecast 时, 其Get()方法会访问 http://SayHelloService/Hello/NetCore, 这就相当于一次远程调用, 只是调用的就是这个WebApi的/Hello/NetCore

1. appsettings.json 增加

"ConsulDiscoveryOptions": {"ConsulServerSetting": {"IP": "127.0.0.1", // 必填"Port": 8500, // 必填"RefreshIntervalInMilliseconds": 1000},"ServiceRegisterSetting": {"ServiceName": "SayHelloService", // 必填"ServiceIP": "127.0.0.1", // 必填"ServicePort": 5000, // 必填"ServiceScheme": "http", // 只能是http 或者 https, 默认http, "HealthCheckRelativeUrl": "/HealthCheck","HealthCheckIntervalInMilliseconds": 500,"HealthCheckTimeOutInMilliseconds": 2000}}

2.修改Startup.cs

using ConsulDiscovery.HttpClient;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using System;namespace WebApplication1
{public class Startup{public Startup(IConfiguration configuration){Configuration = configuration;}public IConfiguration Configuration { get; }public void ConfigureServices(IServiceCollection services){services.AddControllers();// 注册 ConsulDiscovery 相关配置services.AddConsulDiscovery(Configuration);// 配置 SayHelloService 的HttpClientservices.AddHttpClient("SayHelloService", c =>{c.BaseAddress = new Uri("http://SayHelloService");}).AddHttpMessageHandler<DiscoveryHttpMessageHandler>();}public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IHostApplicationLifetime lifetime){if (env.IsDevelopment()){app.UseDeveloperExceptionPage();}app.UseRouting();app.UseAuthorization();app.UseEndpoints(endpoints =>{endpoints.MapControllers();});// 启动 ConsulDiscoveryapp.StartConsulDiscovery(lifetime);}}
}

3. 添加 HelloController

using Microsoft.AspNetCore.Mvc;namespace WebApplication1.Controllers
{[ApiController][Route("[controller]")]public class HelloController : ControllerBase{[HttpGet][Route("{name}")]public string Get(string name){return $"Hello {name}";}}
}

4. 修改WeatherForecast

using Microsoft.AspNetCore.Mvc;
using System.Net.Http;
using System.Threading.Tasks;namespace WebApplication1.Controllers
{[ApiController][Route("[controller]")]public class WeatherForecastController : ControllerBase{private readonly IHttpClientFactory httpClientFactory;public WeatherForecastController(IHttpClientFactory httpClientFactory){this.httpClientFactory = httpClientFactory;}[HttpGet]public async Task<string> Get(){var httpClient = httpClientFactory.CreateClient("SayHelloService");var result = await httpClient.GetStringAsync("Hello/NetCore");return $"WeatherForecast return:      {result}";}}
}
using Microsoft.AspNetCore.Mvc;
using System.Net.Http;
using System.Threading.Tasks;namespace WebApplication1.Controllers
{[ApiController][Route("[controller]")]public class WeatherForecastController : ControllerBase{private readonly IHttpClientFactory httpClientFactory;public WeatherForecastController(IHttpClientFactory httpClientFactory){this.httpClientFactory = httpClientFactory;}[HttpGet]public async Task<string> Get(){var httpClient = httpClientFactory.CreateClient("SayHelloService");var result = await httpClient.GetStringAsync("Hello/NetCore");return $"WeatherForecast return:      {result}";}}
}

5. 启动consul