hey everyone, beginner question: i have a flow that looks like this:

with Flow('fiege_po_uploads', schedule=cron_schedule) as fiege_po_uploads:
    po_nos_query = build_po_nos_query.map(brand=brands)
    po_nos = snowflake_queryfetch.map(
        query=po_nos_query, upstream_tasks=[po_nos_query])
    po_query = build_po_data_query.map(
        po_no=po_nos, brand=brands, upstream_tasks=[po_nos])

brands is a list of 2 strings. in the third task I'm trying to use 2 mapped arguments and i can kinda understand that this doesn't really work. however what is the proper way to do something like this? i'm a complete beginner to both prefect and anything functional, so i probably have a conceptual misunderstanding here. essentially what i'm trying to do here is having an outside loop over

brands

, an inside loop over

po_nos

, and be able to use the value of

brands

in every inner iteration.

is the list of brands something you want to parameterize? did you consider just making a list of queries and then mapping that?

the list of queries approach doesn't really work in my case cause i have a few more tasks further down in the flow that also want to use

brand

. i ended up just making a copy of the flow and hardcoding the brand in both, but that doesn't feel right 😅

would you be able to show the snowflake_queryfetch function? just be sure to take out credentials (if they are there)

Got it. Will digest this and get back to you

thanks 🙂 time for weekend for me anyways xD

from typing import Tuple, List from prefect import Flow, task @task def func_one(x): return f”func_one {x}” @task def func_two(y): return f”func_two {y}” @task def func_three(other_string, x): print(f”{x}, {other_string}“) return f”{x}, {other_string}” @task def cross_prod(x_list, y_list) -> Tuple[List, List]: test = [(x, y) for x in x_list for y in y_list] return [x[0] for x in test], [x[1] for x in test] with Flow(“test”) as flow: brands = [“a”, “b”, “c”] po_nos_query = func_one.map(x=brands) po_nos = func_two.map(y=po_nos_query, upstream_tasks=[po_nos_query]) new_list, new_list2 = cross_prod(po_nos, brands) po_query = func_three.map(other_string=new_list, x=new_list2) flow.run()

hmm, i think this would work if the values of

po_nos

is the same for every value of brand, which in my case is unfortunately not the case. e.g. on any given run i might get

[1, 2]

for brand

a

and

[4, 6, 8]

for brand

b

.

Yeah I think this sounds like it would need some restructuring unfortunately. I don’t think Parameters is the answer. It’s probably editing the Python functions. I’ll reply here if I have an idea.