Dependency Injection Freezes Startup of Application

[Spaxterr]

Hello, I'm having some issues that seems to have with DI to do. I have a class that implements SchedulerListenerSupport which looks something like this.

public class DefaultScheduleListener : SchedulerListenerSupport
{
    private readonly ILogger<DefaultScheduleListener> _logger;
    private readonly IScheduler _scheduler;
    private readonly SchedulerDbContext _dbContext;

    public DefaultScheduleListener(ILogger<DefaultScheduleListener> logger, SchedulerDbContext schedulerDbContext, IScheduler scheduler)
    {
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
        _dbContext = schedulerDbContext ?? throw new ArgumentNullException(nameof(schedulerDbContext));
        _scheduler = scheduler ?? throw new ArgumentNullException(nameof(scheduler));
    }
}

However, it seems like trying to inject IScheduler causes my application to freeze half-way through the startup process. I see the following logs before the app just freezes and won't do anything until I stop it.

I am unsure of what to do about this, I have checked for circular dependencies and found none. By using a debugger I've been able to determine that the constructor of this class does not even run before the app freezes. When I remove the IScheduler parameter, the app will run like usual. Are there any other methods of accessing an IScheduler from this class?

[lahma]

You need to inject ISchedulerFactory and then resolve the IScheduler when needed (outside of constructor) with var scheduler = await schedulerFactory.GetScheduler().

[Spaxterr]

Thanks, that works. However it now seems like the UseMicrosoftDependencyInjectionJobFactory no longer works as whenever I try to schedule a new job the following error is thrown.

Quartz.SchedulerException: Problem instantiating class 'scheduler.Job.CustomJob: Cannot instantiate type which has no empty constructor (Parameter 'CustomJob')'

[lahma]

Check ASP.NET Core example: https://github.com/quartznet/quartznet/tree/3.x/src/Quartz.Examples.AspNetCore, it should work (and without UseMicrosoftDependencyInjectionJobFactory ), you should use the latest 3.7 release.

[Spaxterr]

Right, I noticed that it was deprecated so I removed it. I do not see how they are using ISchedulerFactory in their example, but other than that my implementation looks pretty much the same. Correct me if I have got the wrong idea with my DI.

Startup.cs

services.
// ...
.AddSingleton<ISchedulerFactory, StdSchedulerFactory>()
.AddTransient<MyCustomJob>()
// ...

DefaultScheduleListener.cs

    private readonly ILogger<DefaultScheduleListener> _logger;
    private readonly SchedulerDbContext _dbContext;
    private readonly ISchedulerFactory _schedulerFactory;

    public DefaultScheduleListener(ILogger<DefaultScheduleListener> logger, IDispatcher dispatcher, SchedulerDbContext schedulerDbContext, ISchedulerFactory schedulerFactory)
    {
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
        _dbContext = schedulerDbContext ?? throw new ArgumentNullException(nameof(schedulerDbContext));
        _schedulerFactory = schedulerFactory ?? throw new ArgumentNullException(nameof(schedulerFactory));
    }
    
    public async void SomeMethod()
    {
        var scheduler = await _schedulerFactory.GetScheduler();
    }

Reading the stacktrace, it seems like it's using the SimpleJobFactory, is this correct?

[lahma]

You shouldn't register scheduler factory yourself. You should use AddQuartz() like in the example.