服务发现 Consul

一、安装和启动

下载 [Consul](https://www.consul.io/downloads.html)

下载完成后，解压，只有一个consul.exe，把目录添加到环境变量的PATH，注意添加到系统变量，仅仅加入用户变量不起作用。打开cmd，输入

consul agen -dev  // 启动Consul服务

二、在aspnetcore中注册Consul

1. 定义配置项

/// <summary>

/// Consul配置

/// </summary>

public class ConsulOptions

{

    /// <summary>

    /// Consul服务器的地址

    /// </summary>

    public string HttpEndPoint { get; set; }

    /// <summary>

    /// 数据中心名称

    /// </summary>

    public string DataCenter { get; set; }

    /// <summary>

    /// Dns服务器端点

    /// </summary>

    public DnsEndPoint DnsEndPoint { get; set; }

}

/// <summary>

/// Dns节点

/// </summary>

public class DnsEndPoint

{

    /// <summary>

    /// 服务器地址

    /// </summary>

    public string Address { get; set; }

    /// <summary>

    /// 端口

    /// </summary>

    public int Port { get; set; }

    /// <summary>

    /// 转换为IpEndPoint

    /// </summary>

    /// <returns></returns>

    public IPEndPoint ToIpEndPoint()

    {

        return new IPEndPoint(IPAddress.Parse(Address), Port);

    }

}

public class ServiceDiscoveryOptions

{

    /// <summary>

    /// 服务名称

    /// </summary>

    public string ServiceName { get; set; }

    /// <summary>

    /// Consul配置

    /// </summary>

    public ConsulOptions Consul { get; set; }

}

2. 在appsettings.json中添加配置

"ServiceDiscovery": {

    "ServiceName": "webapi1",

    "Consul": {

        "DataCenter": "dc1",

        "HttpEndPoint": "http://127.0.0.1:8500",

        "DnsEndPoint": {

          "Address": "127.0.0.1",

          "Port": 8600

        }

    }

}

3. 在startup中注册配置项

services.Configure<ServiceDiscoveryOptions>(

    Configuration.GetSection("ServiceDiscovery"));

4. 注册IConsulClient服务

services.AddSingleton<IConsulClient>(new ConsulClient(config =>

{

    config.Address = new Uri(Configuration["ServiceDiscovery:Consul:HttpEndPoint"]);

    config.Datacenter = Configuration["ServiceDiscovery:Consul:DataCenter"];

}));

5. 在Configure中将自身注册到Consul服务

ILifeTime的ApplicationStarted，程序启动时注册到Consul，

使用IApplicationBuilder的Feature获取当前启动的ip和端口，作为服务的ID

public static class ApplicationBuilderExtensions

{

    /// <summary>

    /// 获取当前启动应用绑定的IP和端口

    /// </summary>

    public static IEnumerable<Uri> GetAddress(this IApplicationBuilder app)

    {

        var features = app.Properties["server.Features"] as FeatureCollection;

        return features?.Get<IServerAddressesFeature>()

            .Addresses.Select(p => new Uri(p)) ?? new List<Uri>();

    }

}

public void Configure(

    IApplicationBuilder app, IHostingEnvironment env,

    IApplicationLifetime lifetime, IConsulClient consul,

    IOptions<ServiceDiscoveryOptions> serviceDiscoveryOptions)

{

    if (env.IsDevelopment())

    {

        app.UseDeveloperExceptionPage();

    }

    lifetime.ApplicationStarted.Register(() =>

    {

        var addresses = app.GetAddress();

        foreach (var address in addresses)

        {

            var serviceId =

            $"{serviceDiscoveryOptions.Value.ServiceName}_{address.Host}:{address.Port}";

            consul.Agent.ServiceRegister(new AgentServiceRegistration

            {

                ID = serviceId,

                Name = serviceDiscoveryOptions.Value.ServiceName,

                Address = address.Host,

                Port = address.Port,

                Check = new AgentServiceCheck

                {

                    DeregisterCriticalServiceAfter = TimeSpan.FromSeconds(5),

                    Interval = TimeSpan.FromSeconds(5),

                    HTTP = new Uri(address, "api/Health/Check").OriginalString,

                    Timeout = TimeSpan.FromSeconds(5)

                }

            }).Wait();

            lifetime.ApplicationStopped.Register(() =>

            {

                consul.Agent.ServiceDeregister(serviceId).Wait();

            });

        }

    });

    app.UseAuthentication();

    app.UseMvc();

}

三、在项目中使用Consul

1、 定义一个接口

public interface IServiceDiscoveryManager

{

    string GetApi(string serviceName);

}

2、 实现一个Consul的服务发现工具

public class ConsulServiceDiscoveryManager : IServiceDiscoveryManager

{

    private readonly IConsulClient _client;

    private readonly ILogger<ConsulServiceDiscoveryManager> _logger;

    // 手动高亮，忽略大小写，这个很重要

    private readonly ConcurrentDictionary<string, List<string>> _dict =

        new ConcurrentDictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);

    private DateTime _syncTime = DateTime.Now.AddMinutes(-11);

    private static object _lock = new object();

    public ConsulServiceDiscoveryManager(IConsulClient client, ILogger<ConsulServiceDiscoveryManager> logger)

    {

        _client = client;

        _logger = logger;

    }

    private ConcurrentDictionary<string, List<string>> GetAllServices()

    {

        if (_syncTime < DateTime.Now.AddSeconds(-10) || !_dict.Keys.Any())

        {

            _dict.Clear();

            var services = _client.Agent.Services().Result.Response.Select(s => s.Value).GroupBy(s => s.Service);

            foreach (var service in services)

            {

                _dict.TryAdd(service.Key, service.Select(s => $"{s.Address}:{s.Port}").ToList());

            }

            _syncTime = DateTime.Now;

        }

        return _dict;

    }

    public List<string> GetApis(string serviceName)

    {

        if(!GetAllServices().TryGetValue(serviceName, out var hosts))

        {

            return new List<string>();

        }

        return hosts;

    }

    public string GetApi(string serviceName)

    {

        var hosts = GetApis(serviceName);

        var count = hosts.Count();

        if(count == 0)

        {

            return string.Empty;

        }

        else if(count == 1)

        {

            return hosts.First();

        }

        var ran = new Random().Next(0, count);

        return hosts.ElementAt(ran);

    }

}

3、 在ConfigureServices中注册IServiceDiscoveryManager。

捎带把 IHttpConlientFactory 也注册掉，

注意在 appsettings.json 里把之前的 ServiceDiscoverty 的配置项添加进去，

也可以只添加Consul的部分

services.AddSingleton<IConsulClient>(new ConsulClient(config =>

{

    config.Address = new Uri(Configuration["ServiceDiscovery:Consul:HttpEndPoint"]);

    config.Datacenter = Configuration["ServiceDiscovery:Consul:DataCenter"];

}));

services.AddSingleton<IServiceDiscoveryManager, ConsulServiceDiscoveryManager>();

services.AddHttpClient();

4、 在Controller中使用，也可以封装一个Client，后面可以直接用。

public class TestController : Controller

{

    private readonly ILogger<TestController> _logger;

    private readonly IHttpClientFactory _clientFactory;

    private readonly IServiceDiscoveryManager _serviceDiscoveryManager;

    public TestController(ILogger<TestController> logger,

        IConsulClient consul,

        IHttpClientFactory clientFactory,

        IServiceDiscoveryManager serviceDiscoveryManager)

    {

        _logger = logger;

        _clientFactory = clientFactory;

        _serviceDiscoveryManager = serviceDiscoveryManager;

    }

    public IActionResult Index()

    {

        var apiHost = _serviceDiscoveryManager.GetApi("WebApi1");

        using(var client = _clientFactory.CreateClient())

        {

            var result = client.GetAsync($"http://{apiHost}/api/values").Result;

            return Content(result.Content.ReadAsStringAsync().Result);

        }

    }

}

Ocelot 集成 Consul

一、 引入Nuget包

Ocelot

Ocelot.Provider.Consul

二、 在根目录下创建ocelog.json

{

  "ReRoutes": [

    {

      "DownstreamPathTemplate": "/api/{url}",

      "DownstreamScheme": "http",

      "UseServiceDiscovery": true,

      "ServiceName": "WebApi1",

      "LoadBalancerOptions": {

        "Type": "RoundRobin" //轮询

      },

      "UpstreamPathTemplate": "/WebApi1/{url}",

      "UpstreamHttpMethod": [ "Get", "Post" ]

    }

  ],

  "GlobalConfiguration": {

    "BaseUrl": "http://127.0.0.1:5010",

    "ServiceDiscoveryProvider": {

      "Host": "localhost",

      "Port": 8500,

      "Type": "Consul"

    }

  }

}

三、 修改Program.cs，把刚刚创建好的ocelot.json添加到配置项

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>

    WebHost.CreateDefaultBuilder(args)

        .ConfigureAppConfiguration(configuration =>

        {

            configuration.AddJsonFile("ocelot.json");

        })

        .UseUrls("http://localhost:5010")

        .UseStartup<Startup>();

四、 修改Startup，注册服务，使用ocelot的中间件

public void ConfigureServices(IServiceCollection services)

{

    services.AddOcelot().AddConsul();

}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)

{

    if (env.IsDevelopment())

    {

        app.UseDeveloperExceptionPage();

    }

    else

    {

        app.UseExceptionHandler("/Home/Error");

    }

    app.UseOcelot().Wait();

}

五、 一个比较全的配置项说明

{

  "ReRoutes": [

    {//官方文档ReRoutes全节点示例

      //Upstream表示上游请求，即客户端请求到API Gateway的请求

      "UpstreamPathTemplate": "/", //请求路径模板

      "UpstreamHttpMethod": [ //请求方法数组

        "Get"

      ],

      //Downstreamb表示下游请求，即API Gateway转发的目标服务地址

      "DownstreamScheme": "http", //请求协议，目前应该是支持http和https

      "DownstreamHost": "localhost", //请求服务地址，应该是可以是IP及域名

      "DownstreamPort": 51779, //端口号

      "DownstreamPathTemplate": "/", //下游请求地址模板

      "RouteClaimsRequirement": { //标记该路由是否需要认证

        "UserType": "registered" //示例,K/V形式，授权声明，授权token中会包含一些claim，如填写则会判断是否和token中的一致，不一致则不准访问

      },

      //以下三个是将access claims转为用户的Header Claims,QueryString，该功能只有认证后可用

      "AddHeadersToRequest": { //

        "UserType": "Claims[sub] > value[0] > |", //示例

        "UserId": "Claims[sub] > value[1] > |"//示例

      },

      "AddClaimsToRequest": {},

      "AddQueriesToRequest": {},

      "RequestIdKey": "", //设置客户端的请求标识key，此key在请求header中，会转发到下游请求中

      "FileCacheOptions": { //缓存设置

        "TtlSeconds": 15, //ttl秒被设置为15，这意味着缓存将在15秒后过期。

        "Region": "" //缓存region ，可以使用administrator API清除

      },

      "ReRouteIsCaseSensitive": false, //路由是否匹配大小写

      "ServiceName": "", //服务名称，服务发现时必填

      "QoSOptions": { //断路器配置,目前Ocelot使用的Polly

        "ExceptionsAllowedBeforeBreaking": 0, //打开断路器之前允许的例外数量。

        "DurationOfBreak": 0,                 //断路器复位之前，打开的时间(毫秒)

        "TimeoutValue": 0                     //请求超时时间(毫秒)

      },

      "LoadBalancerOptions": {

        "type": "RoundRobin"   // 负载均衡 RoundRobin(轮询)/LeastConnection(最少连接数)

      },

      "RateLimitOptions": { //官方文档未说明

        "ClientWhitelist": [], // 白名单

        "EnableRateLimiting": false, // 是否限流

        "Period": "1m", // 1s,4m,1h,1d

        "PeriodTimespan": 0, // 多少秒之后客户端可以充实

        "Limit": 0 // 一个时间周期最多可以请求的次数

      },

      "AuthenticationOptions": { //认证配置

        "AuthenticationProviderKey": "", //这个key对应的是代码中.AddJWTBreark中的Key

        "AllowedScopes": []//使用范围

      },

      "HttpHandlerOptions": {

        "AllowAutoRedirect": true, //指示请求是否应该遵循重定向响应。 如果请求应该自动遵循来自Downstream资源的重定向响应，则将其设置为true; 否则为假。 默认值是true。

        "UseCookieContainer": true //该值指示处理程序是否使用CookieContainer属性来存储服务器Cookie，并在发送请求时使用这些Cookie。 默认值是true。

      },

      "UseServiceDiscovery": false //使用服务发现，目前Ocelot只支持Consul的服务发现

    }

  ],

  "GlobalConfiguration": {}

}

六、 再来一个简单的不使用Consul的配置项

{

  "ReRoutes": [

    {

      "DownstreamPathTemplate": "/api/{url}",

      "DownstreamScheme": "http",

      "DownstreamHostAndPorts": [

        {

          "Host": "localhost",

          "Port": 5001

        },

        {

          "Host": "localhost",

          "Port": 5002

        }

      ],

      "LoadBalancerOptions": {

        "Type": "RoundRobin"

      },

      "UpstreamPathTemplate": "/UserService/{url}",

      "UpstreamHttpMethod": [ "Get", "Post" ]

    }

  ]

}

七、熔断

引入Nuget包

Ocelot.Provider.Polly