微服务之:从零搭建ocelot网关和consul集群 - 好文

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" /> <
PackageReferenceInclude="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" /> <
PackageReferenceInclude="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.csusing 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 ishttp://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(
1), Interval = TimeSpan.FromSeconds(30), //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(1),
Interval= TimeSpan.FromSeconds(30), 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
": 8500, "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。

如果生成环境是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

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 <https://github.com/liuyl1992/Ocelot.GatewayToConsul>

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