fix(cron): prevent recurring job re-fire on gateway crash/restart loop#3396
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fix(cron): prevent recurring job re-fire on gateway crash/restart loop#3396
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When a gateway crashes mid-job execution (before mark_job_run can persist the updated next_run_at), the job would fire again on every restart attempt within the grace window. For a daily 6:15 AM job with a 2-hour grace, rapidly restarting the gateway could trigger dozens of duplicate runs. Fix: call advance_next_run() BEFORE run_job() in tick(). For recurring jobs (cron/interval), this preemptively advances next_run_at to the next future occurrence and persists it to disk. If the process then crashes during execution, the job won't be considered due on restart. One-shot jobs are left unchanged — they still retry on restart since there's no future occurrence to advance to. This changes the scheduler from at-least-once to at-most-once semantics for recurring jobs, which is the correct tradeoff: missing one daily message is far better than sending it dozens of times.
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Mar 29, 2026
NousResearch#3396) When a gateway crashes mid-job execution (before mark_job_run can persist the updated next_run_at), the job would fire again on every restart attempt within the grace window. For a daily 6:15 AM job with a 2-hour grace, rapidly restarting the gateway could trigger dozens of duplicate runs. Fix: call advance_next_run() BEFORE run_job() in tick(). For recurring jobs (cron/interval), this preemptively advances next_run_at to the next future occurrence and persists it to disk. If the process then crashes during execution, the job won't be considered due on restart. One-shot jobs are left unchanged — they still retry on restart since there's no future occurrence to advance to. This changes the scheduler from at-least-once to at-most-once semantics for recurring jobs, which is the correct tradeoff: missing one daily message is far better than sending it dozens of times.
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Summary
When a gateway crashes mid-job execution (before
mark_job_runcan persist the updatednext_run_at), recurring cron jobs fire again on every restart attempt within the grace window. For a daily 6:15 AM job with a 2-hour grace period, rapidly restarting the gateway could trigger dozens of duplicate runs.Root cause:
tick()callsrun_job()(which spawns a full agent session — potentially minutes of execution) beforemark_job_run()updatesnext_run_aton disk. If the process dies between these two calls, the next restart finds the job still due and fires it again.Reported by: ludw1OP (DietPi user) — their gateway was unstable due to missing
dbus-user-sessionpackage, causing repeated restarts that flooded their Telegram with duplicate morning wake-up messages.Changes
cron/jobs.py— Addedadvance_next_run(job_id): for recurring jobs (cron/interval), preemptively computes and persists the next futurenext_run_atbefore execution begins. One-shot jobs are left alone so they can retry on restart.cron/scheduler.py—tick()now callsadvance_next_run()beforerun_job(). If the process crashes mid-run, the persistednext_run_atis already in the future, preventing re-fire.Semantics change
Recurring jobs move from at-least-once to at-most-once delivery. Missing one scheduled run due to a crash is far better than sending dozens of duplicates in a crash loop.
mark_job_run()still runs after successful execution and re-confirms the next run time.Test plan