微服务之:从零搭建ocelot网关和consul集群

介绍

微服务中有关键的几项技术，其中网关和服务服务发现，服务注册相辅相成。

首先解释几个本次教程中需要的术语

网关 Gateway（API GW / API 网关），顾名思义，是企业 IT 在系统边界上提供给外部访问内部接口服务的统一入口，简化了外部由于多服务协同完成任务时的繁琐配置。网关组件有Kong，ocelot,

服务发现：通过网关访问内部各个微服务，网关要找到所需服务的过程称为服务发现

服务注册：既然有服务发现，前提是要把所需服务提前“录入”，这个录入的过程称为服务注册。服务注册可配置文件（人肉方式不推荐），也可用服务注册组件如Consul或者Eureka等等（推荐）

搭建Consul集群(Windows)

官网下载Consul程序，https://www.consul.io/downloads.html

下载下来就是一个可执行文件Consul.exe

Consul有两种代理模式，一种server,一种client,官方建议Server端达到3台以上才可高可用，但不要太多，太多会给集群间数据同步造成压力，client数量不限。

多个server端之间会选择出一个leader,当一个server的leader宕机则会从其他server端”投票“选择新的leader

实践

这里server我们用2台实验

192.168.74.55

192.168.74.54

1台Client

192.168.74.161

consul启动有两种方式一种是命令行，一种是配置文件的方式。

命令行方式启动一个consul的server端

consul agent -server -ui -bootstrap-expect 2 -data-dir opt/consul/data -node ServerMaster -bind 192.168.74.55 -client 192.168.74.55

关键参数说明

-server：server模式启动

-ui ：开启ui界面（consul.exe内部带了GUI图形界面操作）

 -bootstrap-expect 2：server端到2个时集群生效

-data-dir：consul产生的文件路径（consul自己会产生一下数据存储的位置）

-node：此节点名称

-bind：集群内部通信地址，默认0.0.0.0

-client：此节点绑定的通讯地址

以上只是关键参数，以下是完整参数说明： 

 

但是命令启动很繁琐，所以推荐下面的配置文件的方式启动

在consul同文件夹下建立一个server.json的配置文件

{
  "datacenter": "dc1",
  "data_dir": "opt/consul/data",
  "node_name": "consul-server01",
  "server": true,
  "bootstrap_expect": 2,
  "bind_addr": "192.168.74.55",
  "client_addr": "192.168.74.55",
  "ui":true
}

为了快速启动，再建立一个bat批处理文件runconsul.bat

consul agent -config-dir server.json
pause

双击runconsul.bat启动consul

在192.168.74.54服务器开启一个server端继续以上操作。

命令方式启动

consul agent -server -ui -data-dir opt/consul/data -node Server01 -bind 192.168.74.54 -client 192.168.74.54 -join=192.168.74.55

-join将192.168.74.54加入到192.168.74.55服务器

配置文件方式：

{
  "datacenter": "dc1",
  "data_dir": "opt/consul/data",
  "node_name": "consul-server2",
  "server": true,
  "bind_addr": "192.168.74.54",
  "client_addr": "192.168.74.54",
  "ui":true,
  "retry_join": ["192.168.74.55"],
  "retry_interval": "30s",
  "rejoin_after_leave": true,
  "start_join":["192.168.74.55"]
  }

在192.168.74.161服务器开启一个consul的client端

命令方式：

consul agent -ui -data-dir opt/consul/data -node ServerSlave  -bind 192.168.74.161 -client 192.168.74.161 -join 192.168.74.55

配置文件方式：

{
  "datacenter": "dc1",
  "data_dir": "opt/consul/data",
  "node_name": "consul-client01",
  "server": false,
  "bind_addr": "192.168.74.161",
  "client_addr": "192.168.74.161",
  "ui":true,
  "retry_join": ["192.168.74.55"],
  "retry_interval": "30s",
  "rejoin_after_leave": true,
  "start_join":["192.168.74.55"]
}

效果

简单Consul集群到这里就搭建成功，只要访问三台服务器任意一个都可数据同步，演示：

netcore集成Consul服务注册

首先新建一个ConsulClient的类库

ConsulRegister.csproj所需组件如下：

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Consul" Version="0.7.2.6" />
    <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" Version="2.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.1.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="2.1.0" />
    <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="2.1.0" />
    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="2.1.0" />
  </ItemGroup>

</Project>

 服务发现自动注册，无需手动绑定本机地址，会自动扫描本地ipv4地址和localhost地址，项目中无需再手动创建健康检查接口

ServiceDiscoveryOptions.cs

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsulRegister
{
    /// <summary>
    /// 服务治理第三方组件Consul相关配置参数
    /// </summary>
    public class ServiceDiscoveryOptions
    {
        public string ServiceName { get; set; }

        public ConsulOptions Consul { get; set; }
    }

    public class ConsulOptions
    {
        public string HttpEndPoint { get; set; }
    }
}

RegisterToConsulExtension.cs

using Consul;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Hosting.Server.Features;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Features;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using System;
using System.Linq;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;

namespace ConsulRegister
{
    public static class RegisterToConsulExtension
    {
        /// <summary>
        /// Add Consul
        /// 添加consul
        /// </summary>
        /// <param name="services"></param>
        /// <param name="configuration"></param>
        /// <returns></returns>
        public static IServiceCollection AddConsul(this IServiceCollection services, IConfiguration configuration)
        {
            // configuration Consul register address
            //配置consul注册地址
            services.Configure<ServiceDiscoveryOptions>(configuration.GetSection("ServiceDiscovery"));

            //configuration Consul client
            //配置consul客户端
            services.AddSingleton<IConsulClient>(sp => new Consul.ConsulClient(config =>
            {
                var consulOptions = sp.GetRequiredService<IOptions<ServiceDiscoveryOptions>>().Value;
                if (!string.IsNullOrWhiteSpace(consulOptions.Consul.HttpEndPoint))
                {
                    config.Address = new Uri(consulOptions.Consul.HttpEndPoint);
                }
            }));

            return services;
        }

        /// <summary>
        /// use Consul
        /// 使用consul
        /// The default health check interface format is http://host:port/HealthCheck
        /// 默认的健康检查接口格式是 http://host:port/HealthCheck
        /// </summary>
        /// <param name="app"></param>
        /// <returns></returns>
        public static IApplicationBuilder UseConsul(this IApplicationBuilder app)
        {
            IConsulClient consul = app.ApplicationServices.GetRequiredService<IConsulClient>();
            IApplicationLifetime appLife = app.ApplicationServices.GetRequiredService<IApplicationLifetime>();
            IOptions<ServiceDiscoveryOptions> serviceOptions = app.ApplicationServices.GetRequiredService<IOptions<ServiceDiscoveryOptions>>();
            var features = app.Properties["server.Features"] as FeatureCollection;

            var port = new Uri(features.Get<IServerAddressesFeature>()
                .Addresses
                .FirstOrDefault()).Port;
            Console.ForegroundColor = ConsoleColor.Blue;
            Console.WriteLine($"application port is :{port}");
            var addressIpv4Hosts = NetworkInterface.GetAllNetworkInterfaces()
            .OrderByDescending(c => c.Speed)
            .Where(c => c.NetworkInterfaceType != NetworkInterfaceType.Loopback && c.OperationalStatus == OperationalStatus.Up);

            foreach (var item in addressIpv4Hosts)
            {
                var props = item.GetIPProperties();
                //this is ip for ipv4
                //这是ipv4的ip地址
                var firstIpV4Address = props.UnicastAddresses
                    .Where(c => c.Address.AddressFamily == AddressFamily.InterNetwork)
                    .Select(c => c.Address)
                    .FirstOrDefault().ToString();
                var serviceId = $"{serviceOptions.Value.ServiceName}_{firstIpV4Address}:{port}";

                var httpCheck = new AgentServiceCheck()
                {
                    DeregisterCriticalServiceAfter = TimeSpan.FromMinutes(),
                    Interval = TimeSpan.FromSeconds(),
                    //this is default health check interface
                    //这个是默认健康检查接口
                    HTTP = $"{Uri.UriSchemeHttp}://{firstIpV4Address}:{port}/HealthCheck",
                };

                var registration = new AgentServiceRegistration()
                {
                    Checks = new[] { httpCheck },
                    Address = firstIpV4Address.ToString(),
                    ID = serviceId,
                    Name = serviceOptions.Value.ServiceName,
                    Port = port
                };

                consul.Agent.ServiceRegister(registration).GetAwaiter().GetResult();

                //send consul request after service stop
                //当服务停止后想consul发送的请求
                appLife.ApplicationStopping.Register(() =>
                {
                    consul.Agent.ServiceDeregister(serviceId).GetAwaiter().GetResult();
                });

                Console.ForegroundColor = ConsoleColor.Blue;
                Console.WriteLine($"health check service:{httpCheck.HTTP}");
            }

            //register localhost address
            //注册本地地址
            var localhostregistration = new AgentServiceRegistration()
            {
                Checks = new[] { new AgentServiceCheck()
                {
                    DeregisterCriticalServiceAfter = TimeSpan.FromMinutes(),
                    Interval = TimeSpan.FromSeconds(),
                    HTTP = $"{Uri.UriSchemeHttp}://localhost:{port}/HealthCheck",
                } },
                Address = "localhost",
                ID = $"{serviceOptions.Value.ServiceName}_localhost:{port}",
                Name = serviceOptions.Value.ServiceName,
                Port = port
            };

            consul.Agent.ServiceRegister(localhostregistration).GetAwaiter().GetResult();

            //send consul request after service stop
            //当服务停止后想consul发送的请求
            appLife.ApplicationStopping.Register(() =>
            {
                consul.Agent.ServiceDeregister(localhostregistration.ID).GetAwaiter().GetResult();
            });

            app.Map("/HealthCheck", s =>
            {
                s.Run(async context =>
                {
                    await context.Response.WriteAsync("ok");
                });
            });
            return app;
        }
    }
}

再新建一个.netcore的webapi项目WebA，并且引用ConsulRegister项目

在WebA项目中的Startup.cs文件中加入Consul服务

 public void ConfigureServices(IServiceCollection services)
        {
 services.AddConsul(Configuration);
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        }

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

            app.UseConsul();
            app.UseMvc();
        }

在WebA项目的appsettings.json配置文件中加入以下Consul服务端配置

{
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "AllowedHosts": "*",

  "ServiceDiscovery": {
    "ServiceName": "A",
    "Consul": {
      "HttpEndpoint": "http://192.168.74.161:8500"
    }
  }
}

这里服务注册就算完成

Ocelot网关搭建

接下来继续Ocelot借助于Consul实现服务发现

新建项目Ocelot.Gateway

将以下依赖加入Ocelot.Gateway.csproj中：

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Ocelot" Version="12.0.1" />
    <PackageReference Include="Ocelot.Provider.Consul" Version="0.1.2" />
  </ItemGroup>

  <ItemGroup>
    <Content Update="ocelot.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </Content>
  </ItemGroup>

</Project>

新建ocelot.json文件

{
  "ReRoutes": [
    {
      "UseServiceDiscovery": true,
      "DownstreamPathTemplate": "/{url}",
      "DownstreamScheme": "http",
      "ServiceName": "A",
      "LoadBalancerOptions": {
        "Type": "RoundRobin"
      },
      "UpstreamPathTemplate": "/a/{url}",
      "UpstreamHttpMethod": [ "Get", "Post" ],
      "ReRoutesCaseSensitive": false
    }
  ],
  "GlobalConfiguration": {
    // 使用Consul服务治理
    "ServiceDiscoveryProvider": {
      "Host": "192.168.74.161",
      "Port": ,
      "ConfigurationKey": "Oceolot_A" //存储在Consul上的Key
    }
  }
}

修改Startup.cs文件如下：

   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.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

            services.AddOcelot(
                 new ConfigurationBuilder()
                 .AddJsonFile("ocelot.json", optional: false, reloadOnChange: true).Build())
                 .AddConsul()
                 .AddConfigStoredInConsul();
        }

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

            app.UseHttpsRedirection();
            app.UseOcelot().Wait();
        }
    }

发布WebA后复制两份分别启动

dotnet WebA.dll --urls="http://0.0.0.0:2001"

dotnet WebA.dll --urls="http://0.0.0.0:2002"

到这里相当于2001和2002程序简单集群了一下

可以发现日志中有 http://192.168.74.161:2002/HealthCheck调用信息：

这其实是consul进行健康检查进行的调用。

启动多个程序后，打开浏览器打开Consuld界面会发现注册了两个服务

这里ocelot网关和consul的服务注册和发现就算初步集成。

生产部署

如果生产环境是windows的情况，将consul做成windwos服务即可

sc create "ConsulServer" binPath="F:\XXX\consul.exe agent -config-dir XXX.json"

生产环境是linux则借助systemd做成守护进程即可

生产环境是docker，运行以下命令部署单节点，集群类似

docker run --restart=always -d --name=c13 -p : consul agent -server -bootstrap -ui -data-dir tmp/consul -bind 0.0.0.0 -client 0.0.0.0 -node dockerserver

目前集群搭建成功，但是连接的话如果指定某个端点的ip进行连接，端点宕机，就会导致网关一样无法连接consul进行服务发现。所以还需进行配置暴露一个端点让客户端连接，配置详情：https://www.consul.io/docs/connect/configuration.html

不过也可以做成虚拟ip进行多台consul的负载。客户端连接虚拟ip即可

项目地址：

github地址