dsh-cron

In the DSH Automation ecosystem, event-driven triggers are handled by dsh-webhook, but time-driven scenarios—firing an agent session at a specific minute, day, or fixed timestamp—lacked a dedicated trigger adapter. dsh-cron fills that gap: it is a durable calendar adapter that normalizes five-field cron expressions, RFC 3339 one-shot timestamps, and IANA-timezone-aware recurring schedules into idempotent fresh-Session Run submissions to the Automation engine, without ever executing an agent turn itself.

The design centers on determinism. Every calendar occurrence is persisted before submission and assigned a stable identity derived from the job id and scheduled instant; if the process crashes after Automation commits but before the source store records the Run id, a restart resubmits the same idempotency key and receives the same Run, eliminating duplicates. Missed recurring occurrences follow a latest-only catch-up policy, while one-shot tasks remain as durable history after firing. In multi-process deployments, only the scheduler-lock holder arms timers and reconciles the event feed, while peer processes expose management services and take over seamlessly after the holder exits; management writes use a separate short-lived lock with three-way merge to prevent overwrites or delete collisions.

It suits teams that need cron-granularity orchestration of agent workflows, particularly in multi-worker environments, cross-timezone scheduling, and production deployments where crash recovery and idempotency are non-negotiable. If you are already running dsh-automation for event-driven pipelines, dsh-cron slots in as the scheduling half, and together they form a complete time-and-event dual-trigger system.