Class JobExecutor
- Namespace
- MailFathom.Application.Jobs.Execution
- Assembly
- MailFathom.Application.dll
Runs one leased job through its handler, holds the lease while it works, and records how it ended.
public sealed class JobExecutor- Inheritance
-
JobExecutor
- Inherited Members
Remarks
Three things can stop a handler and they are not the same event. Host shutdown gives the lease back, so the job is claimable immediately and the deployment costs it nothing; the execution timeout records a failure, because the job exceeded what it was allowed; and a lost lease writes nothing at all, because the row already belongs to the attempt that replaced this one. Collapsing the three would make a rolling restart read as a burst of failures and would let a late writer overwrite a newer attempt's outcome.
The lease is renewed while the handler works, so a job that legitimately takes longer than one lease is not reclaimed underneath it. A renewal the store refuses is the signal that it already was: the attempt is cancelled at once, so the handler stops rather than going on to produce a second execution's effects.
Every write recording an outcome is made outside the caller's cancellation, deliberately. The one moment a result most needs to be durable is the shutdown that stopped the work, and a write cancelled by the same token as the handler would leave the job held until its lease ran out on its own.
A failure is classified before the attempt budget is consulted, which is what keeps a permanent failure from spending the budget several times over to reach the answer it had on its first attempt. Only a transient failure is scheduled again, on a jittered delay; a permanent one, and a transient one that has run out of attempts, becomes a dead letter that keeps the classification and the reason it ended on.
Constructors
- JobExecutor(IJobStore, JobHandlerRegistry, IJobFailureClassifier, JobExecutionSettings, TimeProvider)
Initializes the executor from the queue it writes to and the bounds it runs under.
Methods
- ExecuteAsync(LeasedJob, CancellationToken)
Runs one job this process holds a lease on, and records the outcome against it.