Recover from trigger ERROR state after Job constructor threw an exception?

Question

When using Quartz.net to schedule jobs, I occasionally receive an exception when instantiating a job. This, in turn causes Quartz to set the trigger for the job to an error state. When this occurs, the trigger will cease firing until some manual intervention occurs (restarting the service since I'm using in-memory job scheduling).

How can I prevent the error state from being set, or at the very least, tell Quartz to retry triggers that are in the error state?

The reason for the exception is due to flaky network calls that are required to get configuration data that is passed in to the job's constructor. I'm using a custom IJobFactory to do this.

I've seen other references to this without resolutions:

• https://groups.google.com/forum/#!topic/quartznet/8qaT70jfJPw
• http://forums.terracotta.org/forums/posts/list/2881.page

Answer 1

For the record, I consider this a design flaw of Quartz. If a job can't be constructed once, that doesn't mean it can't always be constructed. This is a transient error and should be treated as such. Stopping all future scheduled jobs violates the principle of least astonishment.

Anyway, my hack solution is to catch any errors that are the result of my job construction and instead of throwing an error or returning null to return a custom IJob instead that simply logs an error. This isn't perfect, but at least it doesn't prevent future triggering of the job.

public IJob NewJob(TriggerFiredBundle bundle, IScheduler scheduler)
{
    try
    {
        var job = this.container.Resolve(bundle.JobDetail.JobType) as IJob;
        return job;
    }
    catch (Exception ex)
    {
        this.logger.Error(ex, "Exception creating job. Giving up and returning a do-nothing logging job.");
        return new LoggingJob(this.logger);
    }
}