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>
69 lines
1.5 KiB
Markdown
69 lines
1.5 KiB
Markdown
---
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title: Use Patching for Safe Workflow Upgrades
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impact: LOW
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impactDescription: Deploy breaking changes without disrupting in-progress workflows
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tags: patching, upgrade, versioning, migration
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---
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## Use Patching for Safe Workflow Upgrades
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Use `DBOS.patch()` to safely deploy breaking workflow changes. Breaking changes alter what steps run or their order.
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**Incorrect (breaking change without patch):**
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```python
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# Original
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@DBOS.workflow()
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def workflow():
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foo()
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bar()
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# Updated - breaks in-progress workflows!
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@DBOS.workflow()
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def workflow():
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baz() # Replaced foo() - checkpoints don't match
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bar()
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```
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**Correct (using patch):**
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```python
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# Enable patching in config
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config: DBOSConfig = {
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"name": "my-app",
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"enable_patching": True,
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}
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DBOS(config=config)
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@DBOS.workflow()
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def workflow():
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if DBOS.patch("use-baz"):
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baz() # New workflows use baz
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else:
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foo() # Old workflows continue with foo
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bar()
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```
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Deprecating patches after all old workflows complete:
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```python
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# Step 1: Deprecate (runs all workflows, stops inserting marker)
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@DBOS.workflow()
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def workflow():
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DBOS.deprecate_patch("use-baz")
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baz()
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bar()
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# Step 2: Remove entirely (after all deprecated workflows complete)
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@DBOS.workflow()
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def workflow():
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baz()
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bar()
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```
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`DBOS.patch(name)` returns:
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- `True` for new workflows (started after patch deployed)
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- `False` for old workflows (started before patch deployed)
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Reference: [Patching](https://docs.dbos.dev/python/tutorials/upgrading-workflows#patching)
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