3分钟掌握Quartz.net分布式定时任务的姿势

长话短说，今天聊一聊分布式定时任务，我的流水账笔记：

ASP.NET Core+Quartz.Net实现web定时任务
AspNetCore结合Redis实践消息队列

细心朋友稍一分析，就知道还有问题：
水平扩展后的WebApp的Quartz.net定时任务会多次触发，因为webapp实例使用的是默认的RAMJobStore, 多实例在内存中都维护了Job和Trigger的副本.

我的定时任务是同步任务，多次执行倒是没有太大问题，但对于特定业务的定时任务，多次执行可能是致命问题。

基于此，来看看Quartz.net 分布式定时任务的姿势

AdoJobStore

很明显，水平扩展的多实例需要一个独立于web实例的机制来存储Job和Trigger.

Quartz.NET提供ADO.NET JobStore来存储任务数据。

先使用SQL脚本在数据库中生成指定的表结构

执行脚本之后，会看到数据库中多出几个以 QRTZ_开头的表

配置Quartz.net使用AdoJobStore

可采用编码形式或者 quartz.config形式添加配置

快速实践

1. 预先生成Job、Trigger表

从https://github.com/quartznet/quartznet/tree/master/database/tables 下载合适的数据库表脚本，生成指定的表结构

2. 添加AdoJobStore

本次使用编码方式添加AdoJobStore配置。
首次启动会将代码中Job和Trigger持久化到sqlite，后面就直接从sqlite中加载Job和Trigger

using System;
using System.Collections.Specialized;
using System.Data;
using System.Threading.Tasks;
using Microsoft.Data.Sqlite;
using Microsoft.Extensions.Logging;
using Quartz;
using Quartz.Impl;
using Quartz.Impl.AdoJobStore.Common;
using Quartz.Spi;namespace EqidManager
{using IOCContainer = IServiceProvider;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);DbProvider.RegisterDbMetadata("sqlite-custom", new DbMetadata(){AssemblyName = typeof(SqliteConnection).Assembly.GetName().Name,ConnectionType = typeof(SqliteConnection),CommandType = typeof(SqliteCommand),ParameterType = typeof(SqliteParameter),ParameterDbType = typeof(DbType),ParameterDbTypePropertyName = "DbType",ParameterNamePrefix = "@",ExceptionType = typeof(SqliteException),BindByName = true});var properties = new NameValueCollection{["quartz.jobStore.type"] = "Quartz.Impl.AdoJobStore.JobStoreTX, Quartz",["quartz.jobStore.useProperties"] = "true",["quartz.jobStore.dataSource"] = "default",["quartz.jobStore.tablePrefix"] = "QRTZ_",["quartz.jobStore.driverDelegateType"] = "Quartz.Impl.AdoJobStore.SQLiteDelegate, Quartz",["quartz.dataSource.default.provider"] = "sqlite-custom",["quartz.dataSource.default.connectionString"] = "Data Source=EqidManager.db",["quartz.jobStore.lockHandler.type"] = "Quartz.Impl.AdoJobStore.UpdateLockRowSemaphore, Quartz",["quartz.serializer.type"] = "binary"};var schedulerFactory = new StdSchedulerFactory(properties);Scheduler = schedulerFactory.GetScheduler().Result;Scheduler.JobFactory = iocJobfactory;}public async Task<IScheduler> ScheduleJob(){var _eqidCounterResetJob = JobBuilder.Create<EqidCounterResetJob>().WithIdentity("EqidCounterResetJob").Build();var _eqidCounterResetJobTrigger = TriggerBuilder.Create().WithIdentity("EqidCounterResetCron").StartNow()//每天凌晨0s.WithCronSchedule("0 0 0 * * ?")      Seconds,Minutes,Hours，Day-of-Month，Month，Day-of-Week，Year（optional field）.Build();// 这里一定要先判断是否已经从SQlite中加载了Job和Triggerif (!await Scheduler.CheckExists(new JobKey("EqidCounterResetJob")) &&!await Scheduler.CheckExists(new TriggerKey("EqidCounterResetCron"))){await Scheduler.ScheduleJob(_eqidCounterResetJob, _eqidCounterResetJobTrigger);}await Scheduler.Start();return Scheduler;}public void EndScheduler(){if (Scheduler == null){return;}if (Scheduler.Shutdown(waitForJobsToComplete: true).Wait(30000))Scheduler = null;else{}_logger.LogError("Schedule job upload as application stopped");}}
}

上面是Quartz.NET 从sqlite中加载Job和Trigger的核心代码

这里要提示两点：

① IOCJobFactory 是自定义JobFactory，目的是与ASP.NET Core原生依赖注入结合
② 在调度任务的时候，先判断是否已经从sqlite加载了Job和Trigger

3.添加Quartz.Net UI轮子

附赠Quartz.NET的调度UI: CrystalQuartz，方便在界面管理和调度任务
① Install-Package CrystalQuartz.AspNetCore -IncludePrerelease
② Startup启用CrystalQuartz

using CrystalQuartz.AspNetCore;
/** app is IAppBuilder* scheduler is your IScheduler (local or remote)*/
var quartz = app.ApplicationServices.GetRequiredService<QuartzStartup>();
var _schedule = await  quartz.ScheduleJob();
app.UseCrystalQuartz(() => scheduler);

③ 在localhost:YOUR_PORT/quartz地址查看调度