Hi all! Trying to construct some simple pipeline. One of tasks return dict, that I want to unpack in another one:

with Flow("Data collection") as flow:
    params = task(params)
    another_task(**params)

but python raise an error

TypeError: FunctionTask object argument after ** must be a mapping, not FunctionTask

Is there any way to unpack dict from task?

@Artem Andrienko, when you call

task(params)

inside your

with Flow

block, you are not actually calling your task function quite yet. Instead, Prefect is observing that call and building up a computational graph that will be executed later. Therefore, the resulting variable that you called

params

is not actually a dictionary, but a Prefect

Task

object; the dictionary will not be produced until you actually call

flow.run()

. What you should probably do in your flow definition is pass the entire

params

variable to

another_task

like this:

another_task(params)

and unpack the dictionary inside the task, where you can provide any custom logic. When the flow is run, Prefect will collect the dictionary output from

task

and pass it to

another_task

appropriately.

@Artem Andrienko a task can return a dict. see if this example helps you