from prefect import flow
@flow(flow_run_name="{name}-on-{date:%A}")
def my_flow(name: str, date: datetime.datetime):
    pass
# creates a flow run called 'marvin-on-Thursday'
my_flow(name="marvin", date=datetime.datetime.utcnow())

19:24:18.752 | INFO    | prefect.engine - Created flow run 'petite-coucal' for flow 'my-flow'
19:24:20.586 | INFO    | Flow run 'petite-coucal' - Finished in state Completed()

from prefect import flow
def generate_flow_run_name():
    date = datetime.datetime.utcnow()
    return f"{date:%A}-is-a-nice-day"
@flow(flow_run_name=generate_flow_run_name)
def my_flow(name: str):
    pass
# creates a flow run called 'Thursday-is-a-nice-day'
my_flow(name="marvin")

19:24:40.895 | INFO    | prefect.engine - Created flow run 'furry-quail' for flow 'my-flow'
19:24:42.444 | INFO    | Flow run 'furry-quail' - Finished in state Completed()

def get_flow_run_name() -> str:
    flow_name = flow_run.flow_name
    flow_time = datetime.now().strftime("%Y%m%dZ%H%M%S")
    return f"{flow_name}-{flow_time}"