.Net6 WebApi使用Ocelot三步配置负载均衡

一.Net6 WebApi使用Ocelot三步配置负载均衡

1、新建WebApi项目名字为OcelotLoadBalance，去掉Http选项，引入nuget包 Ocelot ，我这里是用最新的18.0.0

1.1 新建webapi项目

1.2 取消勾选HTTPS

1.3 安装Ocelot 包，使用命令：Install-Package Ocelot -Version 18.0.0

2、在OcelotLoadBalance项目根目录下新建Ocelot.json，代码如下：

 1 {
 2   "Routes": [
 3     {
 4       //转发的webapi实际服务地址，此处的everything要跟UpstreamPathTemplate的everything一致才可以
 5       //也就是webapi的访问路径要跟everything一致
 6       "DownstreamPathTemplate": "/api/{everything}",
 7       "DownstreamScheme": "http",
 8       "DownstreamHostAndPorts": [
 9         {
10           "Host": "localhost", // 配置的第一台负载均衡服务器，只启动第一个服务器就可以访问，
11           //但是轮训策略一刷新就会访问第二或者第三台服务器,如果第二或者第三台没有启动就会报错
12           "Port": 7001
13         },
14         {
15           "Host": "localhost", // 配置的第二台负载均衡服务器
16           "Port": 7002
17         },
18         {
19           "Host": "localhost", // 配置的第二台负载均衡服务器
20           "Port": 7003
21         }
22       ],
23       //"UpstreamPathTemplate": "/{everything}",
24       "UpstreamPathTemplate": "/api/{everything}", // 上游请求的模板，即用户真实请求的链接,必须以/开头
25       "UpstreamHttpMethod": [ "Get", "Post" ], //上游请求的http方法，是个数组，你可以写多个
26       "LoadBalancerOptions": { // 负载均衡选项:  LeastConnection : 将请求发往最空闲的那个服务器
27         "Type": "RoundRobin" // RoundRobin ：轮流发送    NoLoadBalance ：不启用负载均衡，总是发往第一个请求或者服务发现的那个服务器
28       }
29     }
30   ],
31   "GlobalConfiguration": {
32     "BaseUrl": ""
33   }
34 }

3、在Program中注入Ocelot服务，并且启动Ocelot，代码如下：

 1 using Ocelot.DependencyInjection;
 2 using Ocelot.Middleware;
 3 
 4 var builder = WebApplication.CreateBuilder(args);
 5 
 6 
 7 builder.Services.AddOcelot(new ConfigurationBuilder() // 注入ocelot服务
 8                 .AddJsonFile("ocelot.json").Build()); // 引用ocelot的配置文件
 9 
10 // Add services to the container.
11 
12 builder.Services.AddControllers();
13 // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
14 builder.Services.AddEndpointsApiExplorer();
15 builder.Services.AddSwaggerGen();
16 
17 var app = builder.Build();
18 
19 // Configure the HTTP request pipeline.
20 if (app.Environment.IsDevelopment())
21 {
22     app.UseSwagger();
23     app.UseSwaggerUI();
24 }
25 
26 app.UseAuthorization();
27 
28 app.MapControllers();
29 
30 //   使用Ocelot服务
31 app.UseOcelot().Wait();
32 
33 app.Run();

以上3步完成，就完成了ocelot负载均衡服务的配置，使用的势轮询策略。剩下的就是编写一个服务，测试负载均衡。

二、新建一个Webapi服务测试负载均衡，为了显示是调用的势哪个端口的服务，需要引入注入配置文件服务

1.1 新建Webapi项目WebApiService1，去掉默认的天气预报controller和天气预报服务文件

1.2 新建一个控制器Service1Controller，里面编写一个服务接口用于显示服务被哪个端口调用，代码如下：

 1 using Microsoft.AspNetCore.Http;
 2 using Microsoft.AspNetCore.Mvc;
 3 
 4 namespace WebApiService1.Controllers
 5 {
 6     [Route("api/[controller]")]
 7     [ApiController]
 8     public class Service1Controller : ControllerBase
 9     {
10         private readonly IConfiguration Configuration;
11 
12         public Service1Controller(IConfiguration configuration)
13         {
14             Configuration = configuration;
15         }
16 
17         [HttpGet]
18         [Route("Service1LoadBalance")]
19         public string Service1LoadBalance()
20         {
21             string result = $"您当前正在访问{Configuration["Service1:Port"].ToString()}端口服务！";
22             return result;
23         }
24     }
25 }

1.3 launchSettings.json 配置如下：主要是修改 "applicationUrl": "http://localhost:7002",中的端口号，这样就可以模拟出服务集群

 1 {
 2   "$schema": "https://json.schemastore.org/launchsettings.json",
 3   "iisSettings": {
 4     "windowsAuthentication": false,
 5     "anonymousAuthentication": true,
 6     "iisExpress": {
 7       "applicationUrl": "http://localhost:54665",
 8       "sslPort": 0
 9     }
10   },
11   "profiles": {
12     "WebApiService1": {
13       "commandName": "Project",
14       "dotnetRunMessages": true,
15       "launchBrowser": true,
16       "launchUrl": "swagger",
17       "applicationUrl": "http://localhost:7002",
18       "environmentVariables": {
19         "ASPNETCORE_ENVIRONMENT": "Development"
20       }
21     },
22     "IIS Express": {
23       "commandName": "IISExpress",
24       "launchBrowser": true,
25       "launchUrl": "swagger",
26       "environmentVariables": {
27         "ASPNETCORE_ENVIRONMENT": "Development"
28       }
29     }
30   }
31 }

1.4 appsettings.json主要添加Service1的ip和端口

 1 {
 2   "Logging": {
 3     "LogLevel": {
 4       "Default": "Information",
 5       "Microsoft.AspNetCore": "Warning"
 6     }
 7   },
 8   "AllowedHosts": "*",
 9   //添加以下配置
10   "Service1": {
11     "IP": "localhost",
12     "Port": "7002"
13   }
14 }

1.5 Program.cs使用默认代码即可

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseAuthorization();

app.MapControllers();

app.Run();