Consul 學習筆記—服務發現

本文轉載自查看原文 2020-10-18 21:55 536 Consul/ docker

前言：

　　上一篇文章簡單實用Consul試下服務注冊，本篇繼續學習Consul中的另外特性：服務發現、KV操作；以及對上篇文章中存在的問題進行解決

問題解決

　在上一篇文章中，注冊服務提示檢查失敗。

　通過排查發現為在docker 中運行的容器中配置的心跳檢查api地址配置錯誤：

  "Consul": {
    "Address": "http://host.docker.internal:8500",
    "HealthCheck": "/api/healthcheck",//心跳檢查api地址
    "Name": "czapigoods",
    "Ip": "host.docker.internal",
    "Port": "5602" //未指定成當前docker運行對於端口
  }

　解決方法(docker修改配置方式)：修改docker中配置文件appsettings.json：

進入docker命令行：docker exec -it 容器id /bin/bash 例如：docker exec -it f38a7a2ddfba /bin/bash
更新軟件列表：apt-get update
安裝vim命令：apt-get install vim
進入appsettings.json 修改：vim appsettings.json
修改appsettings中Consul.Port節點為對於docker映射端口
按Esc鍵，並輸入:wq命令（退出保存修改）
重啟對於容器效果如下

　　Ps：Doker相關操作后面單獨詳細

服務發現

　服務注冊問題解決了，接下來我們了解下服務如何發現；首先創建一個web項目Consul.Client並添加Consul包引用

Install-Package Consul

　1、添加一個服務調用接口ICallService.cs用於調用我們添加的服務

public interface ICallService
{
    /// <summary>
    /// 獲取 Goods Service 返回數據
    /// </summary>
    /// <returns></returns>
    Task<string> GetGoodsService();

    /// <summary>
    /// 獲取 Order Service 返回數據
    /// </summary>
    /// <returns></returns>
    Task<string> GetOrderService();

    /// <summary>
    /// 初始化服務
    /// </summary>
    void InitServices();
}

　2、實現該接口CallService.cs調用Goods、Order的api方法　　

public class CallService : ICallService
{
    private readonly IConfiguration _configuration;
    private readonly ConsulClient _consulClient;

    private ConcurrentBag<string> _serviceAUrls;
    private ConcurrentBag<string> _serviceBUrls;

    private IHttpClientFactory _httpClient;

    public CallService(IConfiguration configuration, IHttpClientFactory httpClient)
    {
        _configuration = configuration;

        _consulClient = new ConsulClient(options =>
        {
            options.Address = new Uri(_configuration["Consul:Address"]);
        });

        _httpClient = httpClient;
    }

    public async Task<string> GetGoodsService()
    {
        if (_serviceAUrls == null)
            return await Task.FromResult("Goods Service Initializing...");

        using var httpClient = _httpClient.CreateClient();

        //隨機獲取一個服務地址調用
        var serviceUrl = _serviceAUrls.ElementAt(new Random().Next(_serviceAUrls.Count()));

        Console.WriteLine("Goods Service：" + serviceUrl);

        var result = await httpClient.GetStringAsync($"{serviceUrl}/goods");

        return result;
    }

    public async Task<string> GetOrderService()
    {
        if (_serviceBUrls == null)
            return await Task.FromResult("Order Service Initializing...");

        using var httpClient = _httpClient.CreateClient();

        //隨機獲取一個服務地址調用
        var serviceUrl = _serviceBUrls.ElementAt(new Random().Next(_serviceBUrls.Count()));

        Console.WriteLine("Order Service：" + serviceUrl);

        var result = await httpClient.GetStringAsync($"{serviceUrl}/order");

        return result;
    }

    public void InitServiceList()
    {
        var serviceNames = new string[] { "czapigoods", "czapiorder" };

        foreach (var item in serviceNames)
        {
            Task.Run(async () =>
            {
                var queryOptions = new QueryOptions
                {
                    WaitTime = TimeSpan.FromMinutes(5)
                };
                while (true)
                {
                    await InitServicesAsync(queryOptions, item);
                }
            });
        }
    }
    private async Task InitServicesAsync(QueryOptions queryOptions, string serviceName)
    {
        //獲取心跳檢查服務
        var result = await _consulClient.Health.Service(serviceName, null, true, queryOptions); if (queryOptions.WaitIndex != result.LastIndex)
        {
            queryOptions.WaitIndex = result.LastIndex;

            var services = result.Response.Select(x => $"http://{x.Service.Address}:{x.Service.Port}");

            if (serviceName == "czapigoods")
            {
                _serviceAUrls = new ConcurrentBag<string>(services);
            }
            else if (serviceName == "czapiorder")
            {
                _serviceBUrls = new ConcurrentBag<string>(services);
            }
        }
    }
}

　3、接下來添加接口依賴注入、以及服務初始化調用　　

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();

        services.AddHttpClient();
　　　　　//依賴注入CallService services.AddSingleton<ICallService, CallService>();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env, ICallService service)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseRouting();

        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });
　　　　 //初始化服務列表調用 service.InitServiceList();
    }
}