本文使用的环境：Windows10 64位 + VS 2019 + .NET Core 3.1
Consul有关介绍：https://www.jianshu.com/p/32dc52f28a14
Consul官方网址：https://www.consul.io/
一、安装Consul
1.官网下载对应版本，并解压出来
2.打开cmd，cd到解压的目录，运行如下其中一条命令
本次演示都在同一台计算机上，所以本文选择命令一；这两条命令请在开发环境使用，生产环境不要使用。
命令一：“consul.exe agent -dev”服务中心的ip地址，将会使用127.0.0.1
命令二：“consul.exe agent -dev -client x.x.x.x”指定服务中心的ip地址
3.命令运行成功后，打开“http://127.0.0.1:8500/”，出现如下画面
二、创建服务
1.服务端项目大体结构：
2.新建.NET Core类库项目，命名为“ClassLibrary”，然后NuGet搜索并安装
“Consul”、“Microsoft.Extensions.Configuration”、“Microsoft.Extensions.Configuration.Json”
Common.cs代码：
1 using Consul;
2 using Microsoft.Extensions.Configuration;
3 using System;
4
5 namespace ClassLibrary
6 {
7 public class Common
8 {
9 public static IConfiguration Configuration { get; }
10 static Common()
11 {
12 Configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json", false, true).Build();
13 }
14
15 /// <summary>
16 /// 需要注册的服务地址
17 /// </summary>
18 public static string ConsulServiceIP
19 {
20 get
21 {
22 return Configuration["Consul:ServiceIP"];
23 }
24 }
25
26 /// <summary>
27 /// 需要注册的服务端口
28 /// </summary>
29 public static int ConsulServicePort
30 {
31 get
32 {
33 string str = Configuration["Consul:ServicePort"];
34 return int.Parse(str);
35 }
36 }
37
38 /// <summary>
39 /// 服务注册
40 /// </summary>
41 public static void ConsulRegister()
42 {
43 ConsulClient client = new ConsulClient(
44 (ConsulClientConfiguration c) =>
45 {
46 c.Address = new Uri(Configuration["Consul:Address"]); //Consul服务中心地址
47 c.Datacenter = Configuration["Consul:DataCenter"]; //指定数据中心，如果未提供，则默认为代理的数据中心。
48 }
49 );
50 string checkUrl = Configuration["Consul:CheckUrl"];
51 client.Agent.ServiceRegister(new AgentServiceRegistration()
52 {
53 ID = Guid.NewGuid().ToString(), //服务编号，不可重复
54 Name = Configuration["Consul:ServiceName"], //服务名称
55 Port = ConsulServicePort, //本程序的端口号
56 Address = ConsulServiceIP, //本程序的IP地址
57 Check = new AgentServiceCheck()
58 {
59 DeregisterCriticalServiceAfter = TimeSpan.FromMilliseconds(1), //服务停止后多久注销
60 Interval = TimeSpan.FromSeconds(5), //服务健康检查间隔
61 Timeout = TimeSpan.FromSeconds(5), //检查超时的时间
62 HTTP = $"http://{ConsulServiceIP}:{ConsulServicePort}{checkUrl}" //检查的地址
63 }
64 });
65 }
66
67 }
68 }
3.新建.NET Core的webapi项目，命名为“ServiceStudent”，把“为HTTPS配置”的勾选去掉
Controller代码：
1 using Microsoft.AspNetCore.Mvc;
2 using System;
3 using System.Collections.Generic;
4
5 namespace ServiceStudent.Controllers
6 {
7 [Route("api/[controller]/[action]")]
8 [ApiController]
9 public class DefaultController : ControllerBase
10 {
11 static List<Student> list = new List<Student>() {
12 new Student(){ ID = "001", StudentName = "学生1", StudentAge = 16 },
13 new Student(){ ID = "002", StudentName = "学生2", StudentAge = 18 },
14 new Student(){ ID = "003", StudentName = "学生3", StudentAge = 17 }
15 };
16
17 /// <summary>
18 /// 健康检查接口
19 /// </summary>
20 [HttpGet]
21 public string Check()
22 {
23 return "1";
24 }
25
26 [HttpGet]
27 public List<Student> GetList()
28 {
29 Console.WriteLine(DateTime.Now.ToString());
30 return list;
31 }
32
33 [HttpGet]
34 public Student GetModel(string id)
35 {
36 Console.WriteLine(DateTime.Now.ToString());
37 return list.Find(t => t.ID == id);
38 }
39 }
40 }
其中有一段健康检查的接口，作用是让服务中心知道服务没有挂掉还能访问，不需要什么业务，所以怎么简单怎么来：
Model代码：
public class Student
{
public string ID { get; set; }
public string StudentName { get; set; }
public int StudentAge { get; set; }
}
appsettings.json的配置，加入"Consul"，注意ServiceIP改为自己电脑的IP（这个不要配置为127.0.0.1，后面访问会不正常）
1 {
2 "Logging": {
3 "LogLevel": {
4 "Default": "Information",
5 "Microsoft": "Warning",
6 "Microsoft.Hosting.Lifetime": "Information"
7 }
8 },
9 "AllowedHosts": "*",
10 "Consul": {
11 "Address": "http://127.0.0.1:8500",
12 "CheckUrl": "/api/Default/Check",
13 "DataCenter": "dc1",
14 "ServiceIP": "192.168.2.119",
15 "ServicePort": 551,
16 "ServiceName": "Student"
17 }
18 }
Program.cs的CreateHostBuilder方法改为：
1 public static IHostBuilder CreateHostBuilder(string[] args) =>
2 Host.CreateDefaultBuilder(args)
3 .ConfigureWebHostDefaults(webBuilder =>
4 {
5 string ip = Common.ConsulServiceIP;
6 int port = Common.ConsulServicePort;
7 webBuilder.UseStartup<Startup>().UseUrls($"http://{ip}:{port}");
8 });
在Startup.cs的Configure方法中加入“ClassLibrary.Common.ConsulRegister();”
这样一个“Student”服务就创建好了，“Teacher”服务也是如法炮制，但是需要改appsettings.json的服务名和端口号，代码就不贴了，请到文章结尾处下载。
三、启动服务
通过命令行来启动，打开cmd，cd到Debug目录，各自运行“dotnet ServiceStudent.dll”和“dotnet ServiceTeacher.dll”。
请检查端口有没有被占用或超出范围，如果失败了，在配置文件中换成其它端口试试。
服务运行成功后，打开“http://127.0.0.1:8500/”，如下画面注册成功
如果出现一项打X，那就是失败，这个服务会在1分钟之后被踢出列表
一个服务可能会部署到多个服务器上，用“Teacher”来模拟下多台机器运行。
前面运行好的服务不要关闭，打开Teacher的Debug目录下的配置文件，
修改它的端口号，服务名不用改，再新开一个cmd，运行“dotnet ServiceTeacher.dll”
那么服务中心就会有变化
四、使用服务
1.客户端项目大体结构：
2.新建.net core类库项目，命名为“ClassLibrary”，然后NuGet搜索并安装
“Consul”、“Microsoft.Extensions.Configuration”
Common.cs代码：
using Consul;
using Microsoft.Extensions.Configuration;
using System;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;
namespace ClassLibrary
{
public class Common
{
public static IConfiguration Configuration { get; }
static Common()
{
Configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json", false, true).Build();
}
public static string ConsulAddress
{
get { return Configuration["ConsulAddress"]; }
}
/// <summary>
/// 获取服务
/// </summary>
public static string GetService(string serviceName)
{
ConsulClient client = new ConsulClient(c => c.Address = new Uri(ConsulAddress));
var response = client.Agent.Services().Result.Response;
//服务名称区分大小写，若要不区分：Equals(serviceName, StringComparison.OrdinalIgnoreCase)
var services = response.Where(s => s.Value.Service.Equals(serviceName)).Select(s => s.Value);
//进行取模，随机取得一个服务器，或者使用其它负载均衡策略
var service = services.ElementAt(Environment.TickCount % services.Count());
return service.Address + ":" + service.Port;
}
/// <summary>
/// 获取服务（异步方法）
/// </summary>
public async Task<string> GetService2(string serviceName)
{
ConsulClient client = new ConsulClient(c => c.Address = new Uri(ConsulAddress));
var response = (await client.Agent.Services()).Response;
//服务名称区分大小写，若要不区分：Equals(serviceName, StringComparison.OrdinalIgnoreCase)
var services = response.Where(s => s.Value.Service.Equals(serviceName)).Select(s => s.Value);
//进行取模，随机取得一个服务器，或者使用其它负载均衡策略
var service = services.ElementAt(Environment.TickCount % services.Count());
return service.Address + ":" + service.Port;
}
public static string HttpGetString(string url)
{
HttpClient httpClient = new HttpClient();
string result = httpClient.GetAsync(url)
.Result.Content.ReadAsStringAsync().Result;
httpClient.Dispose();
return result;
}
public static T HttpGetObject<T>(string url)
{
string result = HttpGetString(url);
return Newtonsoft.Json.JsonConvert.DeserializeObject<T>(result);
}
}
}
3.新建.NET Core的webapi项目，命名为“ClientSite”，把“为HTTPS配置”的勾选去掉
StudentController代码：
1 using ClassLibrary;
2 using Microsoft.AspNetCore.Mvc;
3 using System.Collections.Generic;
4
5 namespace ClientSite.Controllers
6 {
7 [Route("api/[controller]/[action]")]
8 [ApiController]
9 public class StudentController : ControllerBase
10 {
11 [HttpGet]
12 public object GetList()
13 {
14 string ip = Common.GetService("Student");
15 List<Student> list = Common.HttpGetObject<List<Student>>($"http://{ip}/api/Default/GetList");
16 return new
17 {
18 address = ip,
19 data = list
20 };
21 }
22
23 [HttpGet]
24 public object GetModel(string id)
25 {
26 string ip = Common.GetService("Student");
27 Student model = Common.HttpGetObject<Student>($"http://{ip}/api/Default/GetModel?id={id}");
28 return new
29 {
30 address = ip,
31 data = model
32 };
33 }
34 }
35 }
TeacherController代码：
1 using ClassLibrary;
2 using Microsoft.AspNetCore.Mvc;
3 using System.Collections.Generic;
4
5 namespace ClientSite.Controllers
6 {
7 [Route("api/[controller]/[action]")]
8 [ApiController]
9 public class TeacherController : ControllerBase
10 {
11 [HttpGet]
12 public object GetList()
13 {
14 string ip = Common.GetService("Teacher");
15 List<Teacher> list = Common.HttpGetObject<List<Teacher>>($"http://{ip}/api/Default/GetList");
16 return new
17 {
18 address = ip,
19 data = list
20 };
21 }
22
23 [HttpGet]
24 public object GetModel(string id)
25 {
26 string ip = Common.GetService("Teacher");
27 Teacher model = Common.HttpGetObject<Teacher>($"http://{ip}/api/Default/GetModel?id={id}");
28 return new
29 {
30 address = ip,
31 data = model
32 };
33 }
34 }
35 }
appsettings.json加入：
"ConsulAddress": "http://127.0.0.1:8500"
4.用VS启动站点，然后用postman访问
“http://ip:port/api/Student/GetList”
“http://ip:port/api/Student/GetModel?id=002”
多次访问“http://ip:port/api/Teacher/GetList”，则address会随机切换，注意看返回的端口号
