AspNet Core上實現(xiàn)web定時任務實例
作為一枚后端程序狗,項目實踐常遇到定時任務的工作,最容易想到的的思路就是利用Windows計劃任務/wndows service程序/Crontab程序等主機方法在主機上部署定時任務程序/腳本。
但是很多時候,若使用的是共享主機或者受控主機,這些主機不允許你私自安裝exe程序、Windows服務程序。
碼甲會想到在web程序中做定時任務, 目前有兩個方向:
- ①.AspNetCore自帶的HostService, 這是一個輕量級的后臺服務, 需要搭配timer完成定時任務
- ②.老牌Quartz.Net組件,支持復雜靈活的Scheduling、支持ADO/RAM Job任務存儲、支持集群、支持監(jiān)聽、支持插件。
此處我們的項目使用稍復雜的Quartz.net實現(xiàn)web定時任務。
項目背景
最近需要做一個計數(shù)程序:采用redis計數(shù),設定每小時將當日累積數(shù)據(jù)持久化到關系型數(shù)據(jù)庫sqlite。
添加Quartz.Net Nuget 依賴包:<PackageReference Include="Quartz" Version="3.0.6" />
- ①.定義定時任務內容: Job
- ②.設置觸發(fā)條件: Trigger
- ③.將Quartz.Net集成進AspNet Core
頭腦風暴
IScheduler類包裝了上述背景需要完成的第①②點工作 ,SimpleJobFactory定義了生成指定的Job任務的過程,這個行為是利用反射機制調用無參構造函數(shù)構造出的Job實例。下面是源碼:
//----------------選自Quartz.Simpl.SimpleJobFactory類-------------
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();
}
}
}
//------------------節(jié)選自Quartz.Util.ObjectUtils類-------------------------
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]);
}
很多時候,定義的Job任務依賴了其他組件,這時默認的SimpleJobFactory不可用, 需要考慮將Job任務作為依賴注入組件,加入依賴注入容器。
關鍵思路:
①. IScheduler 開放了JobFactory 屬性,便于你控制Job任務的實例化方式;
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的服務架構是以依賴注入為基礎的,利用AspNet Core已有的依賴注入容器IServiceProvider管理Job 服務的創(chuàng)建過程。
編碼實踐
① 定義Job內容:
// -------每小時將redis數(shù)據(jù)持久化到sqlite, 每日凌晨跳針,持久化昨天全天數(shù)據(jù)---------------------
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)
{
// 觸發(fā)時間在凌晨,則同步昨天的計數(shù)
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注冊Job和Trigger:
namespace EqidManager
{
using IOCContainer = IServiceProvider;
// Quartz.Net啟動后注冊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()
// 每隔一小時同步一次
.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 :實現(xiàn)在Timer觸發(fā)的時候注入生成對應的Job組件
/// </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結合ASpNet Core 注入組件;綁定Quartz.Net
//-------------------------------截取自Startup文件------------------------
......
services.AddTransient<UsageCounterSyncJob>(); // 這里使用瞬時依賴注入
services.AddSingleton<QuartzStartup>();
......
// 綁定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 網站低頻訪問導致工作進程進入閑置狀態(tài)的 解決辦法
IIS為網站默認設定了20min閑置超時時間:20分鐘內沒有處理請求、也沒有收到新的請求,工作進程就進入閑置狀態(tài)。
IIS上低頻web訪問會造成工作進程關閉,此時應用程序池回收,Timer等線程資源會被銷毀;當工作進程重新運作,Timer可能會重新生成起效, 但我們的設定的定時Job可能沒有按需正確執(zhí)行。

故為在IIS網站實現(xiàn)低頻web訪問下的定時任務:
設置了Idle TimeOut =0;同時將【應用程序池】->【正在回收】->不勾選【回收條件】
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