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,若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。
码甲会想到在web程序中做定时任务, 目前有两个方向:
- ①.AspNetCore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AspNet 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定义了生成指定的Job任务的过程,这个行为是利用反射机制调用无参构造函数构造出的Job实例。下面是源码:
//----------------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> /// <seealso cref="IJobFactory" /> /// <seealso cref="PropertySettingJobFactory" /> /// <author>James House</author> /// <author>Marko Lahma (.NET)</author> 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> /// <remarks> /// It should be extremely rare for this method to throw an exception - /// basically only the case where there is no way at all to instantiate /// and prepare the Job for execution. When the exception is thrown, the /// Scheduler will move all triggers associated with the Job into the /// <see cref="TriggerState.Error" /> state, which will require human /// intervention (e.g. an application restart after fixing whatever /// configuration problem led to the issue with instantiating the Job). /// </remarks> /// <param name="bundle">The TriggerFiredBundle from which the <see cref="IJobDetail" /> /// and other info relating to the trigger firing can be obtained.</param> /// <param name="scheduler"></param> /// <returns>the newly instantiated Job</returns> /// <throws> SchedulerException if there is a problem instantiating the Job. </throws> 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任务依赖了其他组件,这时默认的SimpleJobFactory不可用, 需要考虑将Job任务作为依赖注入组件,加入依赖注入容器。
关键思路:
①. IScheduler 开放了JobFactory 属性,便于你控制Job任务的实例化方式;
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. AspNet Core的服务架构是以依赖注入为基础的,利用AspNet Core已有的依赖注入容器IServiceProvider管理Job 服务的创建过程。
编码实践
① 定义Job内容:
// -------每小时将redis数据持久化到sqlite, 每日凌晨跳针,持久化昨天全天数据--------------------- public class UsageCounterSyncJob : IJob { private readonly EqidDbContext _context; private readonly IDatabase _redisDB1; private readonly ILogger _logger; public UsageCounterSyncJob(EqidDbContext context, RedisDatabase redisCache, ILoggerFactory loggerFactory) { _context = context; _redisDB1 = redisCache[1]; _logger = loggerFactory.CreateLogger<UsageCounterSyncJob>(); } public async Task Execute(IJobExecutionContext context) { // 触发时间在凌晨,则同步昨天的计数 var _day = DateTime.Now.ToString("yyyyMMdd"); if (context.FireTimeUtc.LocalDateTime.Hour == 0) _day = DateTime.Now.AddDays(-1).ToString("yyyyMMdd"); await SyncRedisCounter(_day); _logger.LogInformation("[UsageCounterSyncJob] Schedule job executed."); } ...... }
②注册Job和Trigger:
namespace EqidManager { using IOCContainer = IServiceProvider; // Quartz.Net启动后注册job和trigger public class QuartzStartup { public IScheduler _scheduler { get; set; } private readonly ILogger _logger; private readonly IJobFactory iocJobfactory; public QuartzStartup(IOCContainer IocContainer, ILoggerFactory loggerFactory) { _logger = loggerFactory.CreateLogger<QuartzStartup>(); iocJobfactory = new IOCJobFactory(IocContainer); var schedulerFactory = new StdSchedulerFactory(); _scheduler = schedulerFactory.GetScheduler().Result; _scheduler.JobFactory = iocJobfactory; } 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() // 每隔一小时同步一次 .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"); } } /// <summary> /// IOCJobFactory :实现在Timer触发的时候注入生成对应的Job组件 /// </summary> public class IOCJobFactory : IJobFactory { protected readonly IOCContainer Container; public IOCJobFactory(IOCContainer 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) { } } }
③结合ASpNet Core 注入组件;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); }
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可能会重新生成起效, 但我们的设定的定时Job可能没有按需正确执行。
故为在IIS网站实现低频web访问下的定时任务:
设置了Idle TimeOut =0;同时将【应用程序池】->【正在回收】->不勾选【回收条件】
以上就是AspNet Core上实现web定时任务实例。一粒灰尘,改变不了大海的明净;一颗石子,阻挡不了江河的前进;一丝乌云,遮挡不了太阳的光辉;一次灾难,破坏不了勇者的励志。更多关于AspNet Core上实现web定时任务实例请关注haodaima.com其它相关文章!