7e5abd504f
Add three DBOS SDK skills with reference documentation for building reliable, fault-tolerant applications with durable workflows. Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
57 lines
1.5 KiB
Markdown
57 lines
1.5 KiB
Markdown
---
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title: Create Scheduled Workflows
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impact: MEDIUM
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impactDescription: Run workflows exactly once per time interval
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tags: scheduled, cron, recurring, timer
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---
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## Create Scheduled Workflows
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Use `@DBOS.scheduled` to run workflows on a schedule. Workflows run exactly once per interval.
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**Incorrect (manual scheduling):**
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```python
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# Don't use external cron or manual timers
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import schedule
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schedule.every(1).minute.do(my_task)
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```
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**Correct (DBOS scheduled workflow):**
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```python
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@DBOS.scheduled("* * * * *") # Every minute
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@DBOS.workflow()
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def run_every_minute(scheduled_time, actual_time):
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print(f"Running at {scheduled_time}")
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do_maintenance_task()
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@DBOS.scheduled("0 */6 * * *") # Every 6 hours
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@DBOS.workflow()
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def periodic_cleanup(scheduled_time, actual_time):
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cleanup_old_records()
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```
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Scheduled workflow requirements:
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- Must have `@DBOS.scheduled` decorator with crontab syntax
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- Must accept two arguments: `scheduled_time` and `actual_time` (both `datetime`)
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- Main thread must stay alive for scheduled workflows
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For apps with only scheduled workflows (no HTTP server):
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```python
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import threading
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if __name__ == "__main__":
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DBOS.launch()
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threading.Event().wait() # Block forever
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```
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Crontab format: `minute hour day month weekday`
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- `* * * * *` = every minute
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- `0 * * * *` = every hour
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- `0 0 * * *` = daily at midnight
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- `0 0 * * 0` = weekly on Sunday
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Reference: [Scheduled Workflows](https://docs.dbos.dev/python/tutorials/scheduled-workflows)
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