Hi @Marvin, on the flow run UI, there is a Retry button that I can retry the current failed flow run. How can I use API to trigger the same behavior as I click the Retry button?

To trigger a retry for a failed flow run using the Prefect API, you need to interact with the Prefect Client to modify the state of the flow run. Unfortunately, the documentation excerpts did not provide a direct function for retrying a flow run, but generally, you would set the flow run's state back to a running or pending state to initiate a retry. Here's a general approach using the Prefect Client: 1. Get the Prefect Client: Use

get_client()

to connect to the Prefect API. 2. Set the Flow Run State: Use the client to set the flow run's state to a state that will trigger a retry, such as

Scheduled

or

Pending

. Here's a mock-up of how you might do this:

python
from prefect.client.orchestration import get_client
from prefect.states import Scheduled
from uuid import UUID

async def retry_flow_run(flow_run_id: UUID):
    async with get_client() as client:
        await client.set_flow_run_state(
            flow_run_id=flow_run_id,
            state=Scheduled()
        )

You should replace

Scheduled()

with the appropriate state that matches the retry behavior you desire. You may need to consult further Prefect documentation or source code to ensure this aligns with your specific needs. For more details, you can explore the Prefect source code or look into the Prefect Client's capabilities.

Hi @Marvin, can I retry a failed flow run of a flow associated with a deployment using API?

To retry a failed flow run associated with a deployment using the Prefect API, you can use the

PrefectClient

to interact with the flow run's state. Here's a general approach: 1. Initialize the Prefect Client: Use

get_client()

to connect to the Prefect API. 2. Set the Flow Run State: Use the client to set the flow run's state to a state that will trigger a retry, such as

Scheduled

. Here's a mock-up of how you might do this:

python
from prefect.client.orchestration import get_client
from prefect.states import Scheduled
from uuid import UUID

async def retry_deployment_flow_run(flow_run_id: UUID):
    async with get_client() as client:
        await client.set_flow_run_state(
            flow_run_id=flow_run_id,
            state=Scheduled()
        )

This code snippet assumes that setting the state to

Scheduled

will effectively retry the flow run. You may need to adjust the state according to your specific deployment setup. For more information, you can explore the Prefect documentation on deployments to understand how deployments interact with flow runs and the API capabilities.

@Marvin Can I use the API

/api/flow_runs/{id}/set_state

to update the failed flow_run state from Failed to Scheduled to achieve retry failed flow run?

Yes, you can use the API endpoint

/api/flow_runs/{id}/set_state

to update the state of a failed flow run to

Scheduled

, which should trigger a retry. This action effectively changes the flow run's state from

Failed

to

Scheduled

, allowing it to be re-executed. Here's a general approach: 1. Make an API Request: Send a POST request to

/api/flow_runs/{id}/set_state

with the appropriate payload to set the state to

Scheduled

. 2. Payload Structure: The payload should specify the new state you want to set. Ensure that the state transition is valid according to Prefect's state management rules. Here's a conceptual example of how you might structure the request:

json
POST /api/flow_runs/{id}/set_state
Content-Type: application/json

{
  "state": {
    "type": "Scheduled",
    "name": "Retry"
  }
}

Make sure to replace

{id}

with the actual flow run ID you wish to retry. This operation assumes you have the necessary permissions and the API is configured to accept such state transitions. For more detailed information, you might want to consult the Prefect documentation on managing states.