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作为一枚后端程序狗&＃xff0c;项目实践常遇到定时任务的工作&＃xff0c;最容易想到的的思路就是利用Windows计划任务/wndows service程序/Crontab程序等主机方法在主机上部署定时任务程序/脚本。
但是很多时候&＃xff0c;使用的是共享主机或者受控主机&＃xff0c;这些主机不允许你私自安装exe程序、Windows服务程序。
web程序中做定时任务&＃xff0c;目前有两个方向&＃xff1a;
① ASP.NET Core自带的HostService&＃xff0c; 这是一个轻量级的后台服务&＃xff0c;需要搭配timer完成定时任务
②老牌Quartz.Net组件&＃xff0c;支持复杂灵活的Scheduling、支持ADO/RAM Job任务存储、支持集群、支持监听、支持插件。
此处我们的项目使用稍复杂的Quartz.net实现web定时任务。
项目背景
最近需要做一个计数程序&＃xff1a;采用redis计数&＃xff0c;设定每小时将当日累积数据持久化到关系型数据库sqlite。
添加Quartz.Net Nuget依赖包
① 定义定时任务内容&＃xff1a;Job
② 设置触发条件&＃xff1a;Trigger
③ 将Quartz.Net集成进ASP.NET Core
头脑风暴
IScheduler类包装了上述背景需要完成的第①②点工作&＃xff0c;
SimpleJobFactory工厂类定义了生成Job任务的过程&＃xff1a;利用反射机制调用无参构造函数形成的Job实例
//----------------选自Quartz.Simpl.SimpleJobFactory类-------------
using System;
using Quartz.Logging;
using Quartz.Spi;
using Quartz.Util;
namespace Quartz.Simpl
{/// /// The default JobFactory used by Quartz - simply calls/// on the job class./// public class SimpleJobFactory : IJobFactory{private static readonly ILog log &＃61; LogProvider.GetLogger(typeof (SimpleJobFactory));/// /// Called by the scheduler at the time of the trigger firing, in order to/// produce a instance on which to call Execute./// public virtual IJob NewJob(TriggerFiredBundle bundle, IScheduler scheduler){IJobDetail jobDetail &＃61; bundle.JobDetail;Type jobType &＃61; jobDetail.JobType;try{if (log.IsDebugEnabled()){log.Debug($"Producing instance of Job &＃39;{jobDetail.Key}&＃39;, class&＃61;{jobType.FullName}");}return ObjectUtils.InstantiateType(jobType);}catch (Exception e){SchedulerException se &＃61; new SchedulerException($"Problem instantiating class &＃39;{jobDetail.JobType.FullName}&＃39;", e);throw se;}}/// /// Allows the job factory to destroy/cleanup the job if needed./// No-op when using SimpleJobFactory./// public virtual void ReturnJob(IJob job){var disposable &＃61; job as IDisposable;disposable?.Dispose();}}
}//------------------节选自Quartz.Util.ObjectUtils类-------------------------public static T InstantiateType(Type type)
{if (type &＃61;&＃61; null){throw new ArgumentNullException(nameof(type), "Cannot instantiate null");}ConstructorInfo ci &＃61; type.GetConstructor(Type.EmptyTypes);if (ci &＃61;&＃61; null){throw new ArgumentException("Cannot instantiate type which has no empty constructor", type.Name);}return (T) ci.Invoke(new object[0]);
}
很多时候&＃xff0c;定义的Job任务依赖了其他服务(该Job定义有参构造函数)&＃xff0c;此时默认的SimpleJobFactory不能满足实例化要求&＃xff0c;考虑自定义Job工厂类。
关键思路&＃xff1a;
① Quartz.Net提供IJobFactory接口&＃xff0c;以便开发者定义灵活的Job工厂类
JobFactories may be of use to those wishing to have their application produce IJob instances via some special mechanism, such as to give the opportunity for dependency injection
② ASP.NET Core是以依赖注入为基础的&＃xff0c;利用ASP.NET Core内置依赖注入容器IServiceProvider管理Job的实例化依赖
编码实践
已经定义好Job类&＃xff1a;UsageCounterSyncJob
自定义Job工厂类:IOCJobFactory
/// /// IOCJobFactory &＃xff1a;在Timer触发的时候产生对应Job实例/// public class IOCJobFactory : IJobFactory{protected readonly IServiceProvider Container;public IOCJobFactory(IServiceProvider container){Container &＃61; container;}//Called by the scheduler at the time of the trigger firing, in order to produce// a Quartz.IJob instance on which to call Execute.public IJob NewJob(TriggerFiredBundle bundle, IScheduler scheduler){return Container.GetService(bundle.JobDetail.JobType) as IJob;}// Allows the job factory to destroy/cleanup the job if needed.public void ReturnJob(IJob job){}}
在Quartz启动过程中应用自定义Job工厂
public class QuartzStartup{public IScheduler _scheduler { get; set; }private readonly ILogger _logger;private readonly IJobFactory iocJobfactory;public QuartzStartup(IServiceProvider IocContainer, ILoggerFactory loggerFactory){_logger &＃61; loggerFactory.CreateLogger();iocJobfactory &＃61; new IOCJobFactory(IocContainer);var schedulerFactory &＃61; new StdSchedulerFactory();_scheduler &＃61; schedulerFactory.GetScheduler().Result;_scheduler.JobFactory &＃61; iocJobfactory;}// Quartz.Net启动后注册job和triggerpublic void Start(){_logger.LogInformation("Schedule job load as application start.");_scheduler.Start().Wait();var UsageCounterSyncJob &＃61; JobBuilder.Create().WithIdentity("UsageCounterSyncJob").Build();var UsageCounterSyncJobTrigger &＃61; TriggerBuilder.Create().WithIdentity("UsageCounterSyncCron").StartNow().WithCronSchedule("0 0 * * * ?") // Seconds,Minutes,Hours&＃xff0c;Day-of-Month&＃xff0c;Month&＃xff0c;Day-of-Week&＃xff0c;Year&＃xff08;optional field&＃xff09;.Build();_scheduler.ScheduleJob(UsageCounterSyncJob, UsageCounterSyncJobTrigger).Wait();_scheduler.TriggerJob(new JobKey("UsageCounterSyncJob"));}public void Stop(){if (_scheduler &＃61;&＃61; null){return;}if (_scheduler.Shutdown(waitForJobsToComplete: true).Wait(30000))_scheduler &＃61; null;else{}_logger.LogCritical("Schedule job upload as application stopped");}}
结合ASP.NET Core依赖注入&＃xff1b;web启动时绑定Quartz.Net
//-------------------------------截取自Startup文件------------------------
......
services.AddTransient(); // 这里使用瞬时依赖注入
services.AddSingleton();
......// 绑定Quartz.Net
public void Configure(IApplicationBuilder app, Microsoft.AspNetCore.Hosting.IApplicationLifetime lifetime, ILoggerFactory loggerFactory)
{var quartz &＃61; app.ApplicationServices.GetRequiredService();lifetime.ApplicationStarted.Register(quartz.Start);lifetime.ApplicationStopped.Register(quartz.Stop);
}
以上&＃xff1a; 我们对接ASP.NET Core依赖注入框架实现了一个自定义的JobFactory&＃xff0c;每次任务触发时创建瞬时Job.
Github地址&＃xff1a;https://github.com/zaozaoniao/ASPNETCore-Quartz.NET.git
附&＃xff1a;IIS网站低频访问导致工作进程进入闲置状态的解决办法
IIS为网站默认设定了20min闲置超时时间&＃xff1a;20分钟内没有处理请求、也没有收到新的请求&＃xff0c;工作进程就进入闲置状态。
IIS上低频web访问会造成工作进程关闭&＃xff0c;此时应用程序池回收&＃xff0c;Timer等线程资源会被销毁&＃xff1b;
当工作进程重新运作&＃xff0c;Timer可能会重新生成&＃xff0c; 但我们的设定的定时Job可能没有按需正确执行。
故为IIS站点实现低频web访问下的定时任务&＃xff1a;可设置IdleTimeOut &＃61;0&＃xff1b;将[应用程序池]->[正在回收]->不勾选[回收条件]
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