140 lines
4.6 KiB
C#
140 lines
4.6 KiB
C#
using Microsoft.Extensions.Hosting;
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using Microsoft.Extensions.Logging;
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using System;
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using System.Threading;
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using System.Threading.Tasks;
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namespace Falcon.SugarApi.TimedBackgroundTask
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{
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/// <summary>
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/// 由定时器驱动的后台任务
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/// </summary>
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public abstract class TimedTask:BackgroundService, IDisposable
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{
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/// <summary>
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/// 日志记录器
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/// </summary>
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protected readonly ILogger? Logger;
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/// <summary>
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/// 心跳计时器
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/// </summary>
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private readonly PeriodicTimer _timer;
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/// <summary>
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/// 运行一次任务
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/// </summary>
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/// <param name="cancellationToken">退出信号</param>
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/// <returns>如果继续执行返回True，否则False</returns>
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public abstract Task<bool> Run(CancellationToken cancellationToken);
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/// <summary>
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/// Timer心跳
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/// </summary>
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public virtual int Heartbeat { get; set; } = 1;
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/// <summary>
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/// 执行计划的Cron串
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/// </summary>
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public virtual string CronSchedule { get; set; } = "30 * * * * *";
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/// <summary>
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/// 获取下次执行任务的计划
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/// </summary>
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public CronExpression Schedule { get; private set; }
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/// <summary>
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/// 任务正在运行
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/// </summary>
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private bool _isRunning = false;
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/// <summary>
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/// 下次执行时间
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/// </summary>
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public DateTime NextTickTime { get; set; } = DateTime.MinValue;
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/// <summary>
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/// 后台任务开始
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/// </summary>
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protected virtual void OnStart(TimedTask t,CancellationToken stoppingToken) { }
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/// <summary>
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/// 后台任务停止
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/// </summary>
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protected virtual void OnStop(TimedTask t,CancellationToken stoppingToken) { }
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/// <summary>
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/// 完成一次执行
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/// </summary>
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protected virtual void OnCompleted(TimedTask t,CancellationToken stoppingToken) { }
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/// <summary>
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/// 执行中发生未处理异常
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/// </summary>
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protected virtual bool OnException(TimedTask t,Exception ex,CancellationToken stoppingToken) {
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return false;
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}
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/// <summary>
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/// 系统服务
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/// </summary>
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public IServiceProvider Service { get; set; }
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/// <summary>
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/// 资源锁
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/// </summary>
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private static object _lock = new object();
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/// <summary>
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/// 构造Timed后台任务
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/// </summary>
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/// <param name="service">服务提供器</param>
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public TimedTask(IServiceProvider service) {
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this.Service = service;
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this.Logger = service.GetService(typeof(ILogger<>).MakeGenericType(GetType())) as ILogger;
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_timer = new PeriodicTimer(TimeSpan.FromSeconds(this.Heartbeat));
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this.Schedule = new CronExpression(this.CronSchedule);
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}
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/// <summary>
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/// 由系统调度执行任务
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/// </summary>
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/// <param name="stoppingToken">退出信号</param>
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/// <returns>无返回</returns>
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protected override async Task ExecuteAsync(CancellationToken stoppingToken) {
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this.OnStart(this,stoppingToken);
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while(await _timer.WaitForNextTickAsync(stoppingToken)) {
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lock(_lock) {
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if(stoppingToken.IsCancellationRequested) {
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break;
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}
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if(this._isRunning || DateTime.Now < this.NextTickTime) {
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continue;
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}
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this._isRunning = true;
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}
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try {
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var goOn = await this.Run(stoppingToken);
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this.OnCompleted(this,stoppingToken);
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if(goOn) {
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continue;
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}
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}
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catch(Exception ex) {
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this.OnException(this,ex,stoppingToken);
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}
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SetNextTick();
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this._isRunning = false;
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}
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this.OnStop(this,stoppingToken);
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}
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private void SetNextTick(string? cronSchedule = null) {
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var s = cronSchedule == null ? this.Schedule : new CronExpression(cronSchedule);
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this.NextTickTime = s.GetNextOccurrence(DateTime.Now);
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}
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/// <summary>
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/// 释放对象
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/// </summary>
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public override void Dispose() {
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this._timer?.Dispose();
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GC.SuppressFinalize(this);
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base.Dispose();
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}
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}
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}
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