ASP.NET Core+Quartz.Net实现web定时任务

作为一枚后端程序狗,项目实践常遇到定时任务的工作,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,使用的是共享主机或者受控主机,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,目前有两个方向:

① ASP.NET Core自带的HostService, 这是一个轻量级的后台服务,需要搭配timer完成定时任务

②老牌Quartz.Net组件,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:采用redis计数,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
<PackageReference Include="Quartz" Version="3.0.6" />

① 定义定时任务内容:Job

② 设置触发条件: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,

SimpleJobFactory工厂类定义了生成Job任务的过程: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
{
    /// <summary>
    /// The default JobFactory used by Quartz - simply calls
    /// <see cref="ObjectUtils.InstantiateType{T}" /> on the job class.
    /// </summary>
    public class SimpleJobFactory : IJobFactory
    {
        private static readonly ILog log = LogProvider.GetLogger(typeof (SimpleJobFactory));
        /// <summary>
        /// Called by the scheduler at the time of the trigger firing, in order to
        /// produce a <see cref="IJob" /> instance on which to call Execute.
        /// </summary>
        public virtual IJob NewJob(TriggerFiredBundle bundle, IScheduler scheduler)
        {
            IJobDetail jobDetail = bundle.JobDetail;
            Type jobType = jobDetail.JobType;
            try
            {
                if (log.IsDebugEnabled())
                {
                    log.Debug($"Producing instance of Job '{jobDetail.Key}', class={jobType.FullName}");
                }
                return ObjectUtils.InstantiateType<IJob>(jobType);
            }
            catch (Exception e)
            {
                SchedulerException se = new SchedulerException($"Problem instantiating class '{jobDetail.JobType.FullName}'", e);
                throw se;
            }
        }
        /// <summary>
        /// Allows the job factory to destroy/cleanup the job if needed.
        /// No-op when using SimpleJobFactory.
        /// </summary>
        public virtual void ReturnJob(IJob job)
        {
            var disposable = job as IDisposable;
            disposable?.Dispose();
        }
    }
}
//------------------节选自Quartz.Util.ObjectUtils类-------------------------
 public static T InstantiateType<T>(Type type)
{
     if (type == null)
     {
          throw new ArgumentNullException(nameof(type), "Cannot instantiate null");
     }
     ConstructorInfo ci = type.GetConstructor(Type.EmptyTypes);
     if (ci == 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,定义的Job任务依赖了其他服务(该Job定义有参构造函数),此时默认的SimpleJobFactory不能满足实例化要求,考虑自定义Job工厂类

关键思路:

① Quartz.Net提供IJobFactory接口,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,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:UsageCounterSyncJob

  1. 自定义Job工厂类:IOCJobFactory
/// <summary>
   /// IOCJobFactory :在Timer触发的时候产生对应Job实例
   /// </summary>
   public class IOCJobFactory : IJobFactory
   {
       protected readonly IServiceProvider Container;
       public IOCJobFactory(IServiceProvider container)
       {
           Container = 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)
       {
       }
   }
  1. 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 = loggerFactory.CreateLogger<QuartzStartup>();
           iocJobfactory = new IOCJobFactory(IocContainer);
           var schedulerFactory = new StdSchedulerFactory();
           _scheduler = schedulerFactory.GetScheduler().Result;
           _scheduler.JobFactory = iocJobfactory;
       }
      // Quartz.Net启动后注册job和trigger
       public void Start()
       {
           _logger.LogInformation("Schedule job load as application start.");
           _scheduler.Start().Wait();
           var UsageCounterSyncJob = JobBuilder.Create<UsageCounterSyncJob>()
              .WithIdentity("UsageCounterSyncJob")
              .Build();
           var UsageCounterSyncJobTrigger = TriggerBuilder.Create()
               .WithIdentity("UsageCounterSyncCron")
               .StartNow()
               .WithCronSchedule("0 0 * * * ?")      // Seconds,Minutes,Hours,Day-of-Month,Month,Day-of-Week,Year(optional field)
               .Build();
           _scheduler.ScheduleJob(UsageCounterSyncJob, UsageCounterSyncJobTrigger).Wait();
           _scheduler.TriggerJob(new JobKey("UsageCounterSyncJob"));
       }
       public void Stop()
       {
           if (_scheduler == null)
           {
               return;
           }
           if (_scheduler.Shutdown(waitForJobsToComplete: true).Wait(30000))
               _scheduler = null;
           else
           {
           }
           _logger.LogCritical("Schedule job upload as application stopped");
       }
   }
  1. 结合ASP.NET Core依赖注入;web启动时绑定Quartz.Net
//-------------------------------截取自Startup文件------------------------
......
services.AddTransient<UsageCounterSyncJob>();      // 这里使用瞬时依赖注入
services.AddSingleton<QuartzStartup>();
......
// 绑定Quartz.Net
public void Configure(IApplicationBuilder app, Microsoft.AspNetCore.Hosting.IApplicationLifetime lifetime, ILoggerFactory loggerFactory)
{
    var quartz = app.ApplicationServices.GetRequiredService<QuartzStartup>();
    lifetime.ApplicationStarted.Register(quartz.Start);
    lifetime.ApplicationStopped.Register(quartz.Stop);
}

以上: 我们对接ASP.NET Core依赖注入框架实现了一个自定义的JobFactory,每次任务触发时创建瞬时Job.

Github地址:https://github.com/zaozaoniao/ASPNETCore-Quartz.NET.git

附: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:20分钟内没有处理请求、也没有收到新的请求,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,此时应用程序池回收,Timer等线程资源会被销毁;

当工作进程重新运作,Timer可能会重新生成, 但我们的设定的定时Job可能没有按需正确执行。

ASP.NET Core+Quartz.Net实现web定时任务

故为IIS站点实现低频web访问下的定时任务:可设置IdleTimeOut =0;将[应用程序池]->[正在回收]->不勾选[回收条件]