Hi everyone 😄 We've recently upgraded to the 0.15.6 Prefect version (both server and flows), but if we use start a flow by another flow by using the

StartFlowRun.run()

this error is shown:

Error during execution of task: ClientError([{'message': '[{\'extensions\': {\'path\': \'$.selectionSet.insert_task_run_artifact.args.objects\', \'code\': \'constraint-violation\'}, \'message\': \'Not-NULL violation. null value in column "tenant_id" violates not-null constraint\'}]', 'locations': [{'line': 2, 'column': 5}], 'path': ['create_task_run_artifact'], 'extensions': {'code': 'INTERNAL_SERVER_ERROR', 'exception': {'message': '[{\'extensions\': {\'path\': \'$.selectionSet.insert_task_run_artifact.args.objects\', \'code\': \'constraint-violation\'}, \'message\': \'Not-NULL violation. null value in column "tenant_id" violates not-null constraint\'}]'}}}])

We are migrating from

0.14.22

version, we are using

server

as the backend in local Can anybody help?

Hi @Stefano Cascavilla when it comes to changes to Server, I’m only aware of an additional --expose flag that you need to add when starting server since 0.15.5: https://docs.prefect.io/orchestration/server/deploy-local

Thanks! I've tried again registering them but still get the same issue

I’m not that familiar with Server, but by looking at the error, perhaps you need to create a tenant?

prefect server create-tenant

Already tried this solution, but with no luck 😞 I created a tenant, I started the flows from that custom new tenant, but still got the same issue

I think I know what’s the issue. You’re probably calling

StartFlowRun

from another task. Have a look at this: https://prefect-community.slack.com/archives/CL09KU1K7/p1632911162461300?thread_ts=1632754964.329100&cid=CL09KU1K7

Actually I'm calling the StartFlowRun.run() inside another task. Would we call it with mapped params if we need? (without calling it into another task?)

@Stefano Cascavilla if all your child flows are within the same project, this is how you could map over flows:

from prefect import Flow, unmapped
from prefect.tasks.prefect import create_flow_run
from prefect.executors import LocalDaskExecutor


with Flow("MasterFlow_Mapped", executor=LocalDaskExecutor()) as flow:
    mapped_flows = create_flow_run.map(
        flow_name=["flow_name_1", "flow_name_2", "flow_name_3"],
        project_name=unmapped("Flow_of_Flows"),
    )

if __name__ == "__main__":
    flow.run()

I tested this and it works - they are ran in parallel. But I’m using the create_flow_run task rather than StartFlowRun. Could you give it a try?

Hi @Anna Geller, thanks for the answer. This was the same situation we already have. I've tried adding the

idempotency_key

param to the

run

invocation, but received the same error.

@Stefano Cascavilla Did you try both versions with

StartFlowRun

and

create_flow_run

above and none of that worked? Can you share your flow code so that we can reproduce the issue?

Just tried with the

create_flow_run

along with

wait_for_flow_run

and worked fine! Thank you so much! 😄

@Anna Geller would you suggest using

create_flow_run

instead of

StartFlowRun

as a best practice?

@ale, at Prefect, we don’t want to give opinionated recommendations 🙂 But overall,

StartFlowRun

was initially built to manage subflows but it did it in a way which combines multiple actions in one task. The new tasks

create_flow_run

,

wait_for_flow_run

and

get_task_run_result

separate the concerns, and are much easier to combine with other tasks - you can read more here.

Hey @Anna Geller thanks for sharing! We’ll definitely look into these new tasks 🙌

I opened an issue for this here