Exception Handler¶

NCronJob, much like ASP.NET, offers a central way to handle exceptions. This is useful when you want to log exceptions or send an E-Mail when a job fails. The exception handler has to inherit from the IExceptionHandler interface.

public class MyExceptionHandler : IExceptionHandler
{
    public Task<bool> TryHandleAsync(JobExecutionContext context, Exception exc, CancellationToken token)
    {
        // Handle the exception
        return Task.FromResult(true);
    }
}

If the TryHandleAsync method returns true, the exception is considered as handled and no other exception handler will be called. If it returns false, the next exception handler will be called, if available.

Therefore the order of registration is important. The first registered exception handler will be called first.

Order of execution with NotificationHandlers¶

All exception handlers are executed before the IJobNotificationHandler for that specific job is called. Independent if the exception handler returns true or false, the IJobNotificationHandler will get the exception passed in.

Exceptions when a job is created¶

If an exception occurs when a job is created and therefore the job can not be executed/scheduled, the exception handler will be called with the exception that occurred (and logs the exception to the active logger). NCronJob will not crash in this case.

Furthermore, if a dependent job is configured that should run when the parent job fails, the dependent job will be executed in this case.