Rescheduling Jobs
Ways to reschedule a job.
Manually Retry
When an unhandled exception escapes a running IJob, Quartz marks the job in an error state. You can then reschedule it by whatever method suits your system.
Using JobExecutionException
JobExecutionException controls whether the job refires immediately.
public async Task Execute(IJobExecutionContext context)
{
try
{
// do work
} catch (Exception ex)
{
throw new JobExecutionException(ex, refireImmediately: true)
{
UnscheduleFiringTrigger = true,
UnscheduleAllTriggers = true
};
}
}
Polly Retries
To retry the job's work, wrap it in a Polly retry policy. Long-running Polly retries hold a job slot, so the scheduler can do less other work.
Self-Rescheduling
If the job needs to wait, say 5 minutes, reschedule it through the scheduler on IJobExecutionContext and let it exit normally.
public async Task Execute(IJobExecutionContext context)
{
// something happens, that tells you to delay the processing
// like getting an HTTP 429 - Too Many requests
var oldTrigger = context.Trigger;
var newTrigger = TriggerBuilder.Create()
.ForJob(context.JobDetail)
.WithIdentity($"{oldTrigger.Key.Name}-retry", oldTrigger.Key.Group)
.StartAt(DateTimeOffset.UtcNow.AddMinutes(5))
.Build();
await context.Scheduler.ScheduleJob(newTrigger);
}
Self-Descheduling
Run the job every 5 minutes (or another suitable cadence) and have it unschedule itself after it succeeds. This is easier to reason about, but the job may still be calling the downstream services.
public async Task Execute(IJobExecutionContext context)
{
// work succeeds
if(success)
{
await context.Scheduler.UnscheduleJob(context.Trigger.Key);
}
}