My Parameter is not being turned into the underlying value inside my task functions

[sierrezinal]

I am using prefect 0.13.12

destdir = '/mnt/users'

@task
def download_from_S3(destdir, day) -> Path:
    newdir = Path(destdir) / day   #   <-- exception here
    newdir.mkdir(parents=False, exist_ok=True)
    newfile = newdir / 'foo'
    with open(newfile, 'w') as outfile:
        outfile.write("hello\nworlds\n123")        
    return newfile

...

with Flow("ETL") as flow:
    destdir = Parameter("destdir")
    day = Parameter("day")

    newfile = download_from_S3(destdir, day)
    res = count_lines(newfile)

flowres = flow.run(
    destdir=destdir,
    day='2020-10-26',
    executor=LocalExecutor())

In the first line of my task download_from_S3, destdir is of type Parameter. Why is it not of type str ?
The execution logs:

[2020-10-28 00:35:28] INFO - prefect.FlowRunner | Beginning Flow run for 'ETL'
[2020-10-28 00:35:28] DEBUG - prefect.FlowRunner | Using executor type LocalExecutor
[2020-10-28 00:35:28] DEBUG - prefect.FlowRunner | Flow 'ETL': Handling state change from Scheduled to Running
[2020-10-28 00:35:28] INFO - prefect.TaskRunner | Task 'destdir': Starting task run...
[2020-10-28 00:35:28] DEBUG - prefect.TaskRunner | Task 'destdir': Handling state change from Pending to Running
[2020-10-28 00:35:28] DEBUG - prefect.TaskRunner | Task 'destdir': Calling task.run() method...
[2020-10-28 00:35:28] DEBUG - prefect.TaskRunner | Task 'destdir': Handling state change from Running to Success
[2020-10-28 00:35:28] INFO - prefect.TaskRunner | Task 'destdir': Finished task run for task with final state: 'Success'
[2020-10-28 00:35:28] INFO - prefect.TaskRunner | Task 'day': Starting task run...
[2020-10-28 00:35:28] DEBUG - prefect.TaskRunner | Task 'day': Handling state change from Pending to Running
[2020-10-28 00:35:28] DEBUG - prefect.TaskRunner | Task 'day': Calling task.run() method...
[2020-10-28 00:35:28] DEBUG - prefect.TaskRunner | Task 'day': Handling state change from Running to Success
[2020-10-28 00:35:28] INFO - prefect.TaskRunner | Task 'day': Finished task run for task with final state: 'Success'
[2020-10-28 00:35:28] INFO - prefect.TaskRunner | Task 'download_from_S3': Starting task run...
[2020-10-28 00:35:28] DEBUG - prefect.TaskRunner | Task 'download_from_S3': Handling state change from Pending to Running
[2020-10-28 00:35:28] DEBUG - prefect.TaskRunner | Task 'download_from_S3': Calling task.run() method...
[2020-10-28 00:35:28] ERROR - prefect.TaskRunner | Unexpected error: TypeError('expected str, bytes or os.PathLike object, not Parameter',)

[cicdw]

Hi @sierrezinal I cannot reproduce; based on the logs you've provided it seems that the code does not match the code that you ran on your machine:

[2020-10-28 00:35:28] INFO - prefect.TaskRunner | Task 'dl': Starting task run...

This suggests another task that isn't in your code snippet - perhaps you might have accidentally hardcoded a Parameter somewhere?

[sierrezinal]

Sorry I updated my comment. I originally had:

@task(name="dl")
def download_from_S3(destdir, day) -> Path:
     pass

[sierrezinal]

Ok. I found the problem.

destdir=destdir,

This is passing in the Parameter.
It is working now