59 lines
1.3 KiB
Markdown
59 lines
1.3 KiB
Markdown
---
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title: Use Durable Sleep for Delayed Execution
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impact: MEDIUM
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impactDescription: Survives restarts and can span days or weeks
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tags: sleep, delay, schedule, durable
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---
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## Use Durable Sleep for Delayed Execution
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Use `DBOS.sleep()` for durable delays that survive restarts. The wakeup time is persisted in the database.
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**Incorrect (regular sleep):**
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```python
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import time
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@DBOS.workflow()
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def delayed_task(delay_seconds, task):
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# Regular sleep is lost on restart!
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time.sleep(delay_seconds)
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run_task(task)
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```
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**Correct (durable sleep):**
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```python
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@DBOS.workflow()
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def delayed_task(delay_seconds, task):
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# Durable sleep - survives restarts
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DBOS.sleep(delay_seconds)
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run_task(task)
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```
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Use cases for durable sleep:
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- Schedule a task for the future
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- Wait between retries
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- Implement delays spanning hours, days, or weeks
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Example: Schedule a reminder:
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```python
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@DBOS.workflow()
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def send_reminder(user_id: str, message: str, delay_days: int):
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# Sleep for days - survives any restart
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DBOS.sleep(delay_days * 24 * 60 * 60)
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send_notification(user_id, message)
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```
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For async workflows, use `DBOS.sleep_async()`:
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```python
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@DBOS.workflow()
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async def async_delayed_task():
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await DBOS.sleep_async(60)
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await run_async_task()
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```
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Reference: [Durable Sleep](https://docs.dbos.dev/python/tutorials/workflow-tutorial#durable-sleep)
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