Hi folks, if I return a dictionary from a task, is there a way to unpack that result into

kwargs

for the next task downstream? Something like;

# returns {"path": "some/restapi/path", "start_time": datetime...}
tasks = generate_tasks(first_set)

# Needs a path and start_time argument
histories = fetch_history.map(**tasks)

But this gives me the error

expression after ** must be a mapping with a "str" key

Hey @Aiden Price, the quick answer is no and you'd need to pass the whole dictionary to the downstream task. The long answer is that tasks are executed in a deferred fashion. But the list access and dictionary access like

x[0]

are evaluated during build time, when that

Task

hasn't resolved yet which causes this error. So you can't perform stuff like tuple unpacking because the values don't exist during build time. You either need an intermediate task to plug out the values, or pass the whole dictionary, but something seems off here. If you perform the

map

, it has to be over a list. If you are supplying a

kwarg

that is the same for all mapped tasks, you mapped need to wrapped it with

unmapped

.

Ah whoops yes I should have removed that

map

call when I simplified my example. In actuality I'm returning a list of dictionaries and wanted to unpack each in the

map

.

Ah that makes sense. I think unpacking it inside the task would be the right approach here

Fair enough, thanks for clarifying that