Background Tasks
Schedule cron and interval tasks that keep running when the main window is closed.
The background task scheduler runs jobs on a cron expression or a fixed interval, even when the main Dockerman window is closed. It is the engine behind stats aggregation, retention cleanup, and image upgrade checks.
How it works
The scheduler uses the system tray to stay alive. When you close the main window, Dockerman moves to the tray and tasks keep running. Quitting the tray icon stops all background tasks, and Dockerman tells you so before it exits.
Built-in task kinds
Dockerman ships with the following task kinds. Each one is pre-registered and can be enabled or configured from the Tasks page.
| Kind | Purpose | Default schedule |
|---|---|---|
stats_aggregation | Rolls up raw 5-second stats samples into 5-minute aggregates | Every 30 minutes |
stats_retention_prune | Deletes expired raw samples (older than 1 hour) and expired aggregates (older than 7 days) | Every 60 minutes |
image_upgrade_check | Checks subscribed images for new versions on their registries | Every 6 hours |
Additional kinds such as auto_backup and auto_prune are planned for future releases.
The Tasks page
Open the Tasks page to see every registered task at a glance.
Each row shows:
- Kind and a human-readable description
- Schedule (cron expression or interval)
- Next run countdown
- Last run time and result (success, failure with error message)
- Enabled toggle
Managing tasks
Change the schedule
Edit the schedule for any task from its row. You can set a cron expression (e.g. 0 */2 * * * for every 2 hours) or a fixed interval in seconds.
Enable or disable
Toggle a task on or off. Disabled tasks stay in the list but do not run until re-enabled.
Run now
Click Run now to trigger a task immediately, regardless of its schedule. The run appears in the task history like any scheduled run.
View history
Expand a task row to see the last N runs with their start time, duration, status, and any error messages.
Data storage
Task definitions and run history are stored in the local SQLite database.
| Table | Contents |
|---|---|
tasks | Task ID, kind, schedule, enabled flag, config, and creation time |
task_runs | Run ID, parent task, start and finish timestamps, status, and error messages |
Tips
The scheduler only runs while Dockerman is in the system tray or the main window is open. If you need tasks to survive a full app quit, a system service mode is planned for a future release.
- Check the Tasks page after a fresh install to make sure
stats_aggregationandstats_retention_pruneare enabled. They are on by default. - If disk usage grows, shorten the retention prune interval or lower the retention window in settings.
- The
image_upgrade_checktask is created automatically when you add your first image upgrade watch.