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>
67 lines
1.6 KiB
Markdown
67 lines
1.6 KiB
Markdown
---
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title: Use Versioning for Blue-Green Deployments
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impact: LOW
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impactDescription: Safely deploy new code with version tagging
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tags: versioning, blue-green, deployment, recovery
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---
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## Use Versioning for Blue-Green Deployments
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DBOS versions workflows to prevent unsafe recovery. Use blue-green deployments to safely upgrade.
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**Incorrect (deploying breaking changes without versioning):**
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```python
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# Deploying new code directly kills in-progress workflows
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# because their checkpoints don't match the new code
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# Old code
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@DBOS.workflow()
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def workflow():
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step_a()
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step_b()
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# New code replaces old immediately - breaks recovery!
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@DBOS.workflow()
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def workflow():
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step_a()
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step_c() # Changed step - old workflows can't recover
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```
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**Correct (using versioning with blue-green deployment):**
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```python
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# Set explicit version in config
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config: DBOSConfig = {
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"name": "my-app",
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"application_version": "2.0.0", # New version
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}
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DBOS(config=config)
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# Deploy new version alongside old version
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# New traffic goes to v2.0.0, old workflows drain on v1.0.0
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# Check for remaining old workflows before retiring v1.0.0
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old_workflows = DBOS.list_workflows(
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app_version="1.0.0",
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status=["PENDING", "ENQUEUED"]
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)
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if len(old_workflows) == 0:
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# Safe to retire old version
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pass
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```
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Fork a workflow to run on a new version:
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```python
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# Fork workflow from step 5 on version 2.0.0
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new_handle = DBOS.fork_workflow(
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workflow_id="old-workflow-id",
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start_step=5,
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application_version="2.0.0"
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)
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```
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Reference: [Versioning](https://docs.dbos.dev/python/tutorials/upgrading-workflows#versioning)
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