Question

在定义了两个依赖于范围服务（ScopedDataAccess）的作业之后，我很难将Quartz 3.0.7与ASP.NET Core 2.2结合使用：

services.AddScoped<IScopedDataAccess, ScopedDataAccess>();

services.AddDbContext<AggregatorContext>(opt => opt.UseSqlServer(configuration.GetConnectionString("Default")));

问题在于两个作业都接收到作用域服务的相同实例（并因此接收到相同的数据库上下文），从而由于并行使用而使上下文崩溃。

我的代码如下：

Startup.cs

工作定义为“作用域”，我希望每个实例都在其自己的“作用域”中运行

private void ConfigureQuartz(IServiceCollection services, params Type[] jobs)
{
    services.AddSingleton<IJobFactory, QuartzJobFactory>();
    services.Add(jobs.Select(jobType => new ServiceDescriptor(jobType, jobType, ServiceLifetime.Scoped)));

    services.AddSingleton(provider =>
    {
        var schedulerFactory = new StdSchedulerFactory();
        var scheduler = schedulerFactory.GetScheduler().Result;

        scheduler.JobFactory = provider.GetService<IJobFactory>();
        scheduler.Start();
        return scheduler;
    });
}

protected void StartJobs(IApplicationBuilder app, IApplicationLifetime lifetime)
{
    var scheduler = app.ApplicationServices.GetService<IScheduler>();
    var configService = app.ApplicationServices.GetService<IConfigurationService>();

    QuartzServicesUtilities.StartJob<ArticleXUserDataRefresherJob>(scheduler, 
        TimeSpan.FromSeconds(configService.ArticleXUserDataRefresherJobPeriod));
    QuartzServicesUtilities.StartJob<LinkDataFetchJob>(scheduler,
        TimeSpan.FromSeconds(configService.LinkDataJobPeriod));

    lifetime.ApplicationStarted.Register(() => scheduler.Start());
    lifetime.ApplicationStopping.Register(() => scheduler.Shutdown());
}

QuartzServicesUtilities

public class QuartzServicesUtilities
{
    public static void StartJob<TJob>(IScheduler scheduler, TimeSpan runInterval)
        where TJob : IJob
    {
        var jobName = typeof(TJob).FullName;

        var job = JobBuilder.Create<TJob>()
            .WithIdentity(jobName)
            .Build();

        var trigger = TriggerBuilder.Create()
            .WithIdentity($"{jobName}.trigger")
            .StartNow()
            .WithSimpleSchedule(scheduleBuilder =>
                scheduleBuilder
                    .WithInterval(runInterval)
                    .RepeatForever())
            .Build();

        scheduler.ScheduleJob(job, trigger);
    }
}

QuartzJobFactory

public class QuartzJobFactory : IJobFactory
{
    private readonly IServiceProvider _serviceProvider;

    public QuartzJobFactory(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }

    public IJob NewJob(TriggerFiredBundle bundle, IScheduler scheduler)
    {
        var jobDetail = bundle.JobDetail;

        var job = (IJob)_serviceProvider.GetService(jobDetail.JobType);
        return job;
    }

    public void ReturnJob(IJob job) { }
}

是否可以使用Quartz.NET为不同的作业获取不同的作用域？

Answer 1

据我所知，使用Quartz是不可能的，我在同样的问题上苦苦挣扎，发现的唯一解决方案是使用ServiceLocator并在Job中显式创建范围。

我以这样的结尾：

// Pseudo-Code
public class MyJob : IJob
{
    private readonly IServiceLocator _serviceLocator;

    public MyJob(IServiceLocator serviceLocator)
    {
        _serviceLocator = serviceLocator;
    }

    public async Task Execute(JobExecutionContext context)
    {
        using(_serviceLocator.BeginScope())
        {
            var worker = _serviceLocator.GetService<MyWorker>();
            await worker.DoWorkAsync();
        }
    }
}

在这种情况下，您的工作人员仍然处于范围内，但工作不再了。因此，您仍然可以在解决方案的其他位置使用Worker，并且范围仍然有效。您需要根据您使用的DI自己实现ServiceLocator，并且IServiceLocator也必须由您定义。

修改

在我们的一个项目中，我们使用以下代码：

/// <summary>
/// A simple service locator to hide the real IOC Container.
/// Lowers the anti-pattern of service locators a bit.
/// </summary>
public interface IServiceLocator
{
    /// <summary>
    /// Begins an new async scope.
    /// The scope should be disposed explicitly.
    /// </summary>
    /// <returns></returns>

    IDisposable BeginAsyncScope();
    /// <summary>
    /// Gets an instance of the given <typeparamref name="TService" />.
    /// </summary>
    /// <typeparam name="TService">Type of the requested service.</typeparam>
    /// <returns>The requested service instance.</returns>
    TService GetInstance<TService>() where TService : class;
}

在此实现中，我们主要使用SimpleInjector：

/// <summary>
/// SimpleInjector implementation of the service locator.
/// </summary>
public class ServiceLocator : IServiceLocator
{
    #region member vars

    /// <summary>
    /// The SimpleInjector container.
    /// </summary>
    private readonly Container _container;

    #endregion

    #region constructors and destructors

    public ServiceLocator(Container container)
    {
        _container = container;
    }

    #endregion

    #region explicit interfaces

    /// <inheritdoc />
    public IDisposable BeginAsyncScope()
    {
        return AsyncScopedLifestyle.BeginScope(_container);
    }

    /// <inheritdoc />
    public TService GetInstance<TService>()
        where TService : class
    {
        return _container.GetInstance<TService>();
    }
}

如您所见，这只是一个简单的包装，但是有助于向消费者隐藏真正的DI框架。希望这对您了解所需的实现有所帮助。

Quartz.NET 3.0似乎在同一范围内启动所有作业

Startup.cs

QuartzServicesUtilities

QuartzJobFactory

1 个答案: