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Strange behaviour with multiple `upstream_tasks` o...
# ask-community
p
Strange behaviour with multiple 
upstream_tasks
on a ShellTask This works:
Copy code
brt_commands = create_brt_command.map(adoc_fp=updated_adocs)
        brt_commands_logged = log(item=brt_commands, desc="BRT commands")
        brts = shell_task.map(
            command=brt_commands, upstream_tasks=[tomogram_fps]
        )
This fails:
Copy code
brt_commands = create_brt_command.map(adoc_fp=updated_adocs)
        brt_commands_logged = log(item=brt_commands, desc="BRT commands")
        brts = shell_task.map(
            command=brt_commands, upstream_tasks=[tomogram_fps, brt_commands_logged]
        )
discourse 1
k
Not 100% sure what the issue is, but the top example likely works if you add 
unmapped(tomogram_fps)
to the upstream_task. Its kind of an interesting edge case between 
.map
and 
upstream_tasks
n
can you describe the failure or share logs?
p
Just to be clear - the top example appears to work already.
Copy code
[2022-04-19 12:56:09-0600] INFO - prefect.TaskRunner | Task 'create_brt_command[0]': Starting task run...
[2022-04-19 12:56:09-0600] INFO - prefect.TaskRunner | Task 'create_brt_command[0]': Finished task run for task with final state: 'Success'
[2022-04-19 12:56:10-0600] INFO - prefect.TaskRunner | Task 'log': Starting task run...
[2022-04-19 12:56:10-0600] INFO - prefect.log | BRT commands : ['/opt/rml/imod/bin/batchruntomo -di /gs1/home/macmenaminpe/tmp/tmpovrvi7nb/dirTemplate.adoc -cp 8 -gpu 1']
[2022-04-19 12:56:10-0600] INFO - prefect.TaskRunner | Task 'log': Finished task run for task with final state: 'Success'
[2022-04-19 12:56:10-0600] INFO - prefect.TaskRunner | Task 'ShellTask': Starting task run...
[2022-04-19 12:56:10-0600] INFO - prefect.TaskRunner | Task 'ShellTask': Finished task run for task with final state: 'Failed'
[2022-04-19 12:56:10-0600] INFO - prefect.TaskRunner | Task 'log': Starting task run...
[2022-04-19 12:56:10-0600] INFO - prefect.log | updated Adoc files : [PosixPath('/gs1/home/macmenaminpe/tmp/tmpovrvi7nb/dirTemplate.adoc')]
[2022-04-19 12:56:10-0600] INFO - prefect.TaskRunner | Task 'log': Finished task run for task with final state: 'Success'
[2022-04-19 12:56:10-0600] INFO - prefect.FlowRunner | Flow run FAILED: some reference tasks failed.
@Kyle McChesney - this idea of doing 
unmapped()
stuff in the upstream_tasks is interesting. I think I have to get my head around that for a second.
k
@Kevin Kho we discussed this at somepoint, do you happen to have the link around
p
ahh... ok, so the upstream_tasks should not be included within the map
n
hold on, because if your first example works then I'm wrong, one sec
k
upstream_tasks=[unmnapped(tomogram_fps), unmapped(brt_commands_logged)]
?
upvote 2
does that work? If I recall the issue was that an upstream task parameter needed to get passed to each mapped instance. By specifying unmapped, you ensure that the same one is used.
p
right - within the map? OK, hold on. I have to get into an annoying VPN and it kills Slack. BRB.
k
Kyle is right
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mapped_task = task_one.map(.., upstream_tasks=[unmnapped(tomogram_fps), unmapped(brt_commands_logged)])
should work if 
tomogram_fps
and 
brt_commands_logged
are not mapped tasks
Making them mapped will map element 1 of the upstream list to element 1 of the downstream list as a dependency so you get weirdness is the lists are not the same length
p
can confirm. @Kyle McChesney is correct. Nice
d
Needed this for my own project so thank you.
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