一、背景
NetCore作为微服务可以注册到服务中心，服务中心可以远程启动、重启、关闭该微服务
二、实现
1、创建一个NetCore 2.0 WebApi项目
2、创建一个进程去管理NetCore程序进程
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public
class
ApplicationManager
{
private
static
ApplicationManager _appManager;
private
IWebHost _web;
private
CancellationTokenSource _tokenSource;
private
bool
_running;
private
bool
_restart;
public
bool
Restarting => _restart;
public
ApplicationManager()
{
_running =
false
;
_restart =
false
;
}
public
static
ApplicationManager Load()
{
if
(_appManager ==
null
)
_appManager =
new
ApplicationManager();
return
_appManager;
}
public
void
Start()
{
if
(_running)
return
;
if
(_tokenSource !=
null
&& _tokenSource.IsCancellationRequested)
return
;
_tokenSource =
new
CancellationTokenSource();
_tokenSource.Token.ThrowIfCancellationRequested();
_running =
true
;
_web =
new
WebHostBuilder()
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseIISIntegration()
.UseStartup<Startup>()
.Build();
_web.Run(_tokenSource.Token);
}
public
void
Stop()
{
if
(!_running)
return
;
_tokenSource.Cancel();
_running =
false
;
}
public
void
Restart()
{
Stop();
_restart =
true
;
_tokenSource =
null
;
}
}
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3、把ApplicationManager加入到Main中
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public
static
void
Main(
string
[] args)
{
try
{
var
appManager = ApplicationManager.Load();
do
{
appManager.Start();
}
while
(appManager.Restarting);
}
catch
(Exception ex)
{
}
}
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4、在程序的ValuesController中实现重启、关闭的Api
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using
System;
using
System.Collections.Generic;
using
System.Linq;
using
System.Threading.Tasks;
using
Microsoft.AspNetCore.Mvc;
namespace
NetCoreWebApiDemo.Controllers
{
[Route(
"api/[controller]"
)]
public
class
ValuesController : Controller
{
private
ApplicationManager appManager = ApplicationManager.Load();
// GET api/values
[HttpGet]
public
IEnumerable<
string
> Get()
{
return
new
string
[] {
"value1"
,
"value2"
};
}
// GET api/values/5
[HttpGet(
"{cmd}"
)]
public
string
Get(
string
cmd)
{
switch
(cmd)
{
case
"restart"
: appManager.Restart();
break
;
case
"stop"
: appManager.Stop();
break
;
case
"start"
: appManager.Start();
break
;
}
return
cmd;
}
// POST api/values
[HttpPost]
public
void
Post([FromBody]
string
value)
{
}
// PUT api/values/5
[HttpPut(
"{id}"
)]
public
void
Put(
int
id, [FromBody]
string
value)
{
}
// DELETE api/values/5
[HttpDelete(
"{id}"
)]
public
void
Delete(
int
id)
{
}
}
}
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6、给程序启动和停止加入日志标签
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using
System;
using
System.Collections.Generic;
using
System.Linq;
using
System.Threading.Tasks;
using
Microsoft.AspNetCore.Builder;
using
Microsoft.AspNetCore.Hosting;
using
Microsoft.Extensions.Configuration;
using
Microsoft.Extensions.DependencyInjection;
using
Microsoft.Extensions.Logging;
using
Microsoft.Extensions.Options;
namespace
NetCoreWebApiDemo
{
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();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public
void
Configure(IApplicationBuilder app, IHostingEnvironment env, IApplicationLifetime lifetime)
{
if
(env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseMvc();
lifetime.ApplicationStarted.Register(OnStart);
//1:应用启动时加载配置,2:应用启动后注册服务中心
lifetime.ApplicationStopped.Register(UnRegService);
//应用停止后从服务中心注销
}
private
void
OnStart()
{
LoadAppConfig();
RegService();
}
private
void
LoadAppConfig()
{
//加载应用配置
Console.WriteLine(
"ApplicationStarted:LoadAppConfig"
);
}
private
void
RegService()
{
//先判断是否已经注册过了
//this code is called when the application stops
Console.WriteLine(
"ApplicationStarted:RegService"
);
}
private
void
UnRegService()
{
//this code is called when the application stops
Console.WriteLine(
"ApplicationStopped:UnRegService"
);
}
}
}
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5、在程序根目录运行dotnet run
访问：http://localhost:51062/api/values,显示：["Value1","Value2"]
访问：http://localhost:51062/api/values/restart:显示restart，再访问http://localhost:51062/api/values正常返回["Value1","Value2"]
访问：http://localhost:51062/api/values/stop，显示：stop,再访问http://localhost:51062/api/values就是404了
stop后由于netcore进程已经被关闭，没有了http监听,通过url方式是无法重新启动了，这里可以借助类似supervisor的工具来停止进程，启动进程。
三、源码地址
https://github.com/andrewfry/AspNetCore-App-Restart
四、其它实现
1、除了上面，还可以通过中间件的形式，实现远程关闭
新增一个中间件的类：
public class RemoteStopMiddleware
{
private RequestDelegate _next;
private const string RequestHeader = "Stop-Application";
private const string ResponseHeader = "Application-Stopped";
public RemoteStopMiddleware(RequestDelegate next)
{
_next = next;
}
public async Task Invoke(HttpContext context, IApplicationLifetime lifetime)
{
if (context.Request.Method == "HEAD" && context.Request.Headers[RequestHeader].FirstOrDefault() == "Yes")
{
context.Response.Headers.Add(ResponseHeader, "Yes");
lifetime.StopApplication();
}
else if (context.Request.Method == "HEAD" && context.Request.Headers[RequestHeader].FirstOrDefault() == "No")
{
context.Response.Headers.Add(ResponseHeader, "No");
// See you on the next request.
//Program.Shutdown();
}
else
{
await _next(context);
}
}
}
2、注册中间件
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public
void
Configure(IApplicationBuilder app, IHostingEnvironment env, IApplicationLifetime lifetime)
{
if
(env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseMvc();
app.UseMiddleware<RemoteStopMiddleware>();
lifetime.ApplicationStarted.Register(OnStart);
//1:应用启动时加载配置,2:应用启动后注册服务中心
lifetime.ApplicationStopped.Register(UnRegService);
//应用停止后从服务中心注销
}
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3、运行程序，用postman发起一个head请求，请求头中加
{
Stop-Application：Yes
}
详细说明可参考：https://www.cnblogs.com/artech/p/application-life-time.html