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>
2.0 KiB
2.0 KiB
title, impact, impactDescription, tags
| title | impact | impactDescription | tags |
|---|---|---|---|
| Cancel, Resume, and Fork Workflows | MEDIUM | Control running workflows and recover from failures | workflow, cancel, resume, fork, control |
Cancel, Resume, and Fork Workflows
Use these methods to control workflow execution: stop runaway workflows, retry failed ones, or restart from a specific step.
Incorrect (expecting immediate cancellation):
DBOS.cancel_workflow(workflow_id)
# Wrong: assuming the workflow stopped immediately
cleanup_resources() # May race with workflow still running its current step
Correct (wait for cancellation to complete):
DBOS.cancel_workflow(workflow_id)
# Cancellation happens at the START of the next step
# Wait for workflow to actually stop
handle = DBOS.retrieve_workflow(workflow_id)
status = handle.get_status()
while status.status == "PENDING":
time.sleep(0.5)
status = handle.get_status()
# Now safe to clean up
cleanup_resources()
Cancel
Stop a workflow and remove it from its queue:
DBOS.cancel_workflow(workflow_id) # Cancels workflow and all children
Resume
Restart a stopped workflow from its last completed step:
# Resume a cancelled or failed workflow
handle = DBOS.resume_workflow(workflow_id)
result = handle.get_result()
# Can also bypass queue for an enqueued workflow
handle = DBOS.resume_workflow(enqueued_workflow_id)
Fork
Start a new workflow from a specific step of an existing one:
# Get steps to find the right starting point
steps = DBOS.list_workflow_steps(workflow_id)
for step in steps:
print(f"Step {step['function_id']}: {step['function_name']}")
# Fork from step 3 (skips steps 1-2, uses their saved results)
new_handle = DBOS.fork_workflow(workflow_id, start_step=3)
# Fork to run on a new application version (useful for patching bugs)
new_handle = DBOS.fork_workflow(
workflow_id,
start_step=3,
application_version="2.0.0"
)
Reference: Workflow Management