Idempotent Jobs
Domain: Automation & Scheduling
Motivation
Idempotent work is safe to re-run, which matters because dsh’s automation layers are not exactly-once: the webhook runtime has no deduplication (repeated deliveries may create repeated sessions), and schedule crash recovery can repeat a delivery. Designing the job so a second run is harmless turns retries into a non-event.
Concrete Example
A job that writes a dated report file keyed by the run date re-runs cleanly, and a webhook rule that checks whether the session already exists before creating one is idempotent across duplicate deliveries.
Analogy
Stamping a document: the second stamp does not change the first.