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Scheduling, Cron, Daemon, and Startup

This document explains how Snoopy runs jobs continuously and survives restarts.

Scheduling Model​

  • Scheduler: node-cron
  • Each enabled job registers one cron task.
  • Default schedule when creating jobs: */30 * * * * (every 30 minutes).

At each tick:

  1. Job is reloaded from DB.
  2. If still enabled, runner executes.
  3. Run stats are persisted in job_runs.
  4. Scanned items are persisted in scan_items for dedupe and auditing.

Daemon Lifecycle​

Commands:

  • snoopy daemon start
  • snoopy daemon stop
  • snoopy daemon status
  • snoopy daemon run

Behavior:

  • daemon start launches detached process and writes PID file.
  • PID file path: <root>/daemon.pid.
  • daemon status verifies PID file and process liveness.
  • daemon run keeps scheduler in foreground and is useful for debugging.

Manual Runs vs Scheduled Runs​

Manual run:

snoopy job run <jobRef> --limit 5

Manual runs are ideal for:

  • quick rubric checks
  • model configuration validation
  • smoke testing new jobs

Scheduled runs are best for continuous monitoring once a job is trusted.

Cron Expressions​

jobs.schedule_cron supports standard cron syntax used by node-cron.

Examples:

  • */30 * * * * every 30 minutes
  • 0 * * * * hourly
  • 0 9 * * * daily at 09:00

Startup-on-Reboot/Login​

Snoopy supports OS startup registration.

Commands:

  • snoopy startup install
  • snoopy startup uninstall
  • snoopy startup enable
  • snoopy startup disable
  • snoopy startup status

Alias group:

  • snoopy reboot enable|disable|status

macOS​

Primary method:

  • launchd LaunchAgent

Status checks for:

  • ~/Library/LaunchAgents/com.snoopy.daemon.plist

Linux​

Preferred method:

  • systemd user service (when available)

Fallback method:

  • cron @reboot entry

Status checks:

  • systemd service file in ~/.config/systemd/user/
  • crontab entry containing snoopy daemon run

Windows​

Preferred method:

  • Task Scheduler job

Fallback method:

  • HKCU Run registry entry

Status checks:

  • schtasks /query /tn "Snoopy\\Daemon"
  • reg query HKCU\Software\Microsoft\Windows\CurrentVersion\Run /v SnoopyDaemon

Operational Recommendations​

  • During setup: run snoopy doctor after configuring settings.
  • Before enabling startup: confirm daemon start works.
  • After reboot registration: verify with startup status and daemon status.
  • For debugging noisy jobs: use manual runs with --limit.