https://prefect.io logo
Join Slack
Powered by
Hello Prefect team :wave:, I'm adding `S3Result` t...
# ask-community
l
Hello Prefect team 👋, I'm adding 
S3Result
to my flows and I have encountered a weird error (template issue?), which I tried to replicate in a minimal example fashion. I'm running the flow through Prefect server which I set up using 
prefect server start
and using local agent 
prefect agent start
. More info in thread
Copy code
3 November 2020,06:11:19 	agent	INFO	Submitted for execution: PID: 12005
3 November 2020,06:11:20 	prefect.CloudFlowRunner	INFO	Beginning Flow run for 'test_flow'
3 November 2020,06:11:20 	prefect.CloudFlowRunner	DEBUG	Using executor type LocalExecutor
3 November 2020,06:11:20 	prefect.CloudFlowRunner	DEBUG	Flow 'test_flow': Handling state change from Scheduled to Running
3 November 2020,06:11:20 	prefect.CloudTaskRunner	INFO	Task 'A': Starting task run...
3 November 2020,06:11:20 	prefect.CloudTaskRunner	DEBUG	Task 'A': Handling state change from Pending to Running
3 November 2020,06:11:20 	prefect.CloudTaskRunner	DEBUG	Task 'A': Calling task.run() method...
3 November 2020,06:11:20 	prefect.S3Result	DEBUG	Starting to upload result to prefect_results/test_flow/03-11_17-11-14/A-3d92ad1d-7818-4d72-8894-58bb01d3cb69.prefect_result...
3 November 2020,06:11:21 	prefect.S3Result	DEBUG	Finished uploading result to prefect_results/test_flow/03-11_17-11-14/A-3d92ad1d-7818-4d72-8894-58bb01d3cb69.prefect_result.
3 November 2020,06:11:21 	prefect.CloudTaskRunner	DEBUG	Task 'A': Handling state change from Running to Success
3 November 2020,06:11:21 	prefect.CloudTaskRunner	INFO	Task 'A': Finished task run for task with final state: 'Success'
3 November 2020,06:11:21 	prefect.CloudTaskRunner	INFO	Task 'B': Starting task run...
3 November 2020,06:11:21 	prefect.CloudTaskRunner	DEBUG	Task 'B': Handling state change from Pending to Running
3 November 2020,06:11:21 	prefect.CloudTaskRunner	DEBUG	Task 'B': Calling task.run() method...
3 November 2020,06:11:21 	prefect.B	INFO	Task B [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
3 November 2020,06:11:21 	prefect.CloudTaskRunner	DEBUG	Task 'B': Handling state change from Running to Success
3 November 2020,06:11:21 	prefect.CloudTaskRunner	INFO	Task 'B': Finished task run for task with final state: 'Success'
3 November 2020,06:11:21 	prefect.CloudTaskRunner	INFO	Task 'C': Starting task run...
3 November 2020,06:11:21 	prefect.S3Result	DEBUG	Starting to download result from prefect_results/{flow_name}/{scheduled_start_time:%d-%m_%H-%M-%S}/{task_full_name}-{task_run_id}.prefect_result...
3 November 2020,06:11:21 	prefect.S3Result	ERROR	Unexpected error while reading from result handler: ClientError('An error occurred (404) when calling the HeadObject operation: Not Found',)
Traceback (most recent call last):
  File "/home/novotl/.cache/pypoetry/virtualenvs/flows-aRCZ5YQu-py3.6/lib/python3.6/site-packages/prefect/engine/results/s3_result.py", line 136, in read
    Bucket=self.bucket, Key=location, Fileobj=stream
  File "/home/novotl/.cache/pypoetry/virtualenvs/flows-aRCZ5YQu-py3.6/lib/python3.6/site-packages/boto3/s3/inject.py", line 678, in download_fileobj
    return future.result()
  File "/home/novotl/.cache/pypoetry/virtualenvs/flows-aRCZ5YQu-py3.6/lib/python3.6/site-packages/s3transfer/futures.py", line 106, in result
    return self._coordinator.result()
  File "/home/novotl/.cache/pypoetry/virtualenvs/flows-aRCZ5YQu-py3.6/lib/python3.6/site-packages/s3transfer/futures.py", line 265, in result
    raise self._exception
  File "/home/novotl/.cache/pypoetry/virtualenvs/flows-aRCZ5YQu-py3.6/lib/python3.6/site-packages/s3transfer/tasks.py", line 255, in _main
    self._submit(transfer_future=transfer_future, **kwargs)
  File "/home/novotl/.cache/pypoetry/virtualenvs/flows-aRCZ5YQu-py3.6/lib/python3.6/site-packages/s3transfer/download.py", line 345, in _submit
    **transfer_future.meta.call_args.extra_args
  File "/home/novotl/.cache/pypoetry/virtualenvs/flows-aRCZ5YQu-py3.6/lib/python3.6/site-packages/botocore/client.py", line 357, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/home/novotl/.cache/pypoetry/virtualenvs/flows-aRCZ5YQu-py3.6/lib/python3.6/site-packages/botocore/client.py", line 661, in _make_api_call
    raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (404) when calling the HeadObject operation: Not Found
3 November 2020,06:11:21 	prefect.CloudTaskRunner	DEBUG	Task 'C': Handling state change from Pending to Failed
3 November 2020,06:11:22 	prefect.CloudTaskRunner	INFO	Task 'C': Finished task run for task with final state: 'Failed'
3 November 2020,06:11:22 	prefect.CloudFlowRunner	DEBUG	Checking flow run state...
3 November 2020,06:11:22 	prefect.CloudFlowRunner	INFO	Flow run FAILED: some reference tasks failed.
3 November 2020,06:11:22 	prefect.CloudFlowRunner	DEBUG	Flow 'test_flow': Handling state change from Running to Failed
Here is the log from the flow, the read from S3 fails, because the location is wrong
And here is the sample flow
Copy code
import os
from typing import List

import prefect
from prefect import Flow, task
from prefect.engine.results import S3Result


@task(name='A')
def task_a() -> List[int]:
    return [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]


@task(name='B')
def task_b(foo: List) -> None:
    <http://prefect.context.logger.info|prefect.context.logger.info>(f'Task B {foo}')


@task(name='C')
def task_c(foo: List[int]) -> None:
    <http://prefect.context.logger.info|prefect.context.logger.info>(f'Task C {foo}')


result = S3Result(
    bucket=os.environ.get('DATA_BUCKET'),
    location='prefect_results/{flow_name}/'
    '{scheduled_start_time:%d-%m_%H-%M-%S}/'
    '{task_full_name}-{task_run_id}.prefect_result',
)

with Flow(name='test_flow', result=result) as flow:
    a = task_a()
    b = task_b(a)
    c = task_c(a)

    flow.set_dependencies(task=c, upstream_tasks=[b])

if __name__ == "__main__":
    flow.register(project_name='default')
Any idea what I'm doing wrong 🙏? When I tested the flow with 
flow.run()
it finished successfully.
b
Running it locally with flow.run may be using your personal .toml file, while the server may be using a different toml file. For us there is a prod.toml that gets baked in.
Oh, I see, you’re using env vars for the bucket. Hmm.
l
Yeah, and actually the local 
flow.run()
and the local agent are run from the same environment
m
Hi Lukas, I run the flow you posted above, it looks like the issue with value for 
location
, but still didn't figure out what's the problem
l
Looks like there is a bug, if you're interested in this you can follow the github issue -> https://github.com/PrefectHQ/prefect/issues/3618
m
Thanks for opening the issue and letting me know 🙏
😉 1
5 Views
Open in Slack
PreviousNext
Powered by