Hi! is it possible to pass some information to the flow run in the UI? Often there is problem, that run depends on current time: for example it downloads data with timestamp equals to previous day and if this run fails and you find later than that day, you have to run the script manually with the appropriate arguments

You could make use of a parameter: https://docs.prefect.io/core/concepts/parameters.html The parameter value can be specified in the UI when running a flow.

@Daniil Ponizov yes, it is possible to pass custom parameter values to any flow run from the UI. You can use Parameter task to do that: • https://docs.prefect.io/core/about_prefect/thinking-prefectly.html#parameters • https://docs.prefect.io/api/latest/core/parameters.html#parameter If you are looking specifically into the backfilling process using Parameters, you can use something like this:

import pendulum
from prefect import task, Flow, Parameter

@task
def get_start_date(param_start_date: str) -> str:
    if param_start_date is None:
        param_start_date = pendulum.yesterday(tz="America/New_York").isoformat()
    return param_start_date

@task
def get_end_date(param_end_date: str) -> str:
    if param_end_date is None:
        param_end_date = pendulum.today(tz="America/New_York").isoformat()
    return param_end_date

@task(log_stdout=True)
def extract_data(start_date: str, end_date: str):
    # your extract logic based on those dates
    print(f"Backloading data for the interval {start_date} - {end_date}")

with Flow("backfilling_flow") as flow:
    custom_start_date = Parameter("start_date", default=None)
    custom_end_date = Parameter("end_date", default=None)
    start_date = get_start_date(custom_start_date)
    end_date = get_end_date(custom_end_date)
    extract_data(start_date=start_date, end_date=end_date)

And to backfill specific dates, you can use

from prefect import task, Flow, unmapped
from prefect.tasks.prefect import create_flow_run

with Flow("trigger") as flow:
    backfill_intervals = [
        dict(
            start_date="2021-11-11T00:00:00-05:00", end_date="2021-11-12T00:00:00-05:00"
        ),
        dict(
            start_date="2021-11-12T00:00:00-05:00", end_date="2021-11-13T00:00:00-05:00"
        ),
        dict(
            start_date="2021-11-13T00:00:00-05:00", end_date="2021-11-14T00:00:00-05:00"
        ),
        dict(
            start_date="2021-11-14T00:00:00-05:00", end_date="2021-11-15T00:00:00-05:00"
        ),
        dict(
            start_date="2021-11-15T00:00:00-05:00", end_date="2021-11-16T00:00:00-05:00"
        ),
        dict(
            start_date="2021-11-16T00:00:00-05:00", end_date="2021-11-17T00:00:00-05:00"
        ),
    ]
    create_flow_run.map(
        flow_name=unmapped("backfilling_flow"),
        project_name=unmapped("p"),
        parameters=backfill_intervals,
    )

Alternatively, you can use the KV store for that purpose: https://docs.prefect.io/orchestration/concepts/kv_store.html#using-key-value-pairs-in-flows

thanks!

if you have some Parameter tasks, you can adjust the inputs as follows:

yeah, this works. Thanks!