Why I am getting this error after upgrade from 2 16 6 to lat Prefect Community #ask-marvin

Why I am getting this error after upgrade from 2.1...

Xun Wang

07/16/2024, 5:16 PM

Why I am getting this error after upgrade from 2.16.6 to latest 2.19.8? Here is the stack trace. Traceback (most recent call last): File "/home/pentaho/anaconda3/envs/py310/lib/python3.10/site-packages/prefect/engine.py", line 454, in retrieve_flow_then_begin_flow_run parameters = flow.validate_parameters(flow_run.parameters) File "/home/pentaho/anaconda3/envs/py310/lib/python3.10/site-packages/prefect/flows.py", line 510, in validate_parameters args, kwargs = parameters_to_args_kwargs(self.fn, parameters) File "/home/pentaho/anaconda3/envs/py310/lib/python3.10/site-packages/prefect/utilities/callables.py", line 181, in parameters_to_args_kwargs raise SignatureMismatchError.from_bad_params( prefect.exceptions.SignatureMismatchError: Function expects parameters ['args', 'kwargs'] but was provided with parameters ['knownhosts', 'remote_file']

Nate

07/16/2024, 5:19 PM

hi @Xun Wang can you share your flow?

Xun Wang

07/16/2024, 5:22 PM

Copy code

@flow(name="ftp_mapping_source_into_db",
      description="Flow FTP to DB default remote file: /ftp/HotelContentExporter_FTPUpload/output/09",
      task_runner=SequentialTaskRunner())
def ftp_mapping_source_into_db(remote_file: str = '/ftp/HotelContentExporter_FTPUpload/output/09',
                               knownhosts: str = None):
        local_file = ftp_to_csv_flow(remote_file, knownhosts)
        source_to_db_task = source_to_db.submit(local_file)
        source_to_db_task.wait()
        summary_of_mapping_sync_src('workflow')

Xun Wang

07/16/2024, 5:25 PM

This is from the cloud console for the above error: Validation of flow parameters failed with error: Traceback (most recent call last): File "/home/pentaho/anaconda3/envs/py310/lib/python3.10/site-packages/prefect/engine.py", line 454, in retrieve_flow_then_begin_flow_run parameters = flow.validate_parameters(flow_run.parameters) File "/home/pentaho/anaconda3/envs/py310/lib/python3.10/site-packages/prefect/flows.py", line 510, in validate_parameters args, kwargs = parameters_to_args_kwargs(self.fn, parameters) File "/home/pentaho/anaconda3/envs/py310/lib/python3.10/site-packages/prefect/utilities/callables.py", line 181, in parameters_to_args_kwargs raise SignatureMismatchError.from_bad_params( prefect.exceptions.SignatureMismatchError: Function expects parameters ['args', 'kwargs'] but was provided with parameters ['knownhosts', 'remote_file']

Nate

07/16/2024, 5:26 PM

can you share the output of the following?

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prefect deployment inspect your-flow/your-deployment

Xun Wang

07/16/2024, 5:28 PM

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{
    'id': '439d81f7-5068-40e6-8227-69e211d9d9cf',
    'created': '2022-09-07T23:56:06.348366+00:00',
    'updated': '2023-10-24T22:05:33.055011+00:00',
    'infra_overrides': {},
    'name': 'vervotech-deployment',
    'version': 'e72dccecba11900b2fd166e5774a0468',
    'description': 'Flow (Vervotech): FTP to DB default remote file: /ftp/HotelContentExporter_FTPUpload/output/09',
    'flow_id': '02fd7e3f-c7e3-4323-b6d0-0da71dff7cb2',
    'schedule': None,
    'is_schedule_active': True,
    'paused': False,
    'schedules': [],
    'parameters': {},
    'pull_steps': None,
    'tags': [],
    'work_queue_name': 'cloud-beta',
    'last_polled': '2024-07-16T17:28:10.139769+00:00',
    'parameter_openapi_schema': {
        'type': 'object',
        'title': 'Parameters',
        'properties': {'knownhosts': {'title': 'knownhosts'}, 'remote_file': {'title': 'remote_file', 'default': '/ftp/HotelContentExporter_FTPUpload/output/09'}}
    },
    'path': '/home/pentaho/prefect2',
    'entrypoint': 'vervotech/vervotech_flow.py:ftp_mapping_source_into_db',
    'manifest_path': None,
    'storage_document_id': None,
    'infrastructure_document_id': '6760e295-85db-42da-9782-18ea923f7355',
    'created_by': None,
    'updated_by': None,
    'work_queue_id': None,
    'enforce_parameter_schema': False,
    'work_pool_name': 'default-agent-pool',
    'status': 'READY',
    'infrastructure': {
        'type': 'process',
        'env': {},
        'labels': {},
        'name': None,
        'command': ['python', '-m', 'prefect.engine'],
        'stream_output': True,
        'working_dir': None,
        'block_type_slug': 'process'
    },
    'automations': []
}

Nate

07/16/2024, 5:31 PM

hmm thats odd

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'parameter_openapi_schema': {
        'type': 'object',
        'title': 'Parameters',
        'properties': {'knownhosts': {'title': 'knownhosts'}, 'remote_file': {'title': 'remote_file', 'default': '/ftp/HotelContentExporter_FTPUpload/output/09'}}
    },

this looks right, which makes this error confusing

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Function expects parameters ['args', 'kwargs']

I will try to reproduce this

🙏 1

Xun Wang

07/16/2024, 9:44 PM

FYI I have run locally and get pass this particular flow param issue. Since there are many other failures in additional to this one. I rolled back to version 2.17.1 which seems to help. At this moment I have to make the flow to run successfully. Will comeback and check on these errors later. I wonder if the original deployment done long time ago has anything to do with this issue since I noticed the way to perform deployment has changed. Please advise if you have found anything to fix on my side. Also any advice to redeploy those flows developed long time ago (during early release of prefect 2.0).

🙏 1

07/19/2024, 5:08 PM

Running into this as well, but on 3.0.0rc11

07/19/2024, 5:57 PM

Untitled.txt

07/19/2024, 5:57 PM

This is weird tbh. I tried to walk through the steps that happen when

engine.py

is ran, which is: 1. using client to load flow run 2. pulling code via

run_steps(deployment.pull_steps)

3. importing flow via

load_flow_from_entrypoint

4. calling

flow_engine._flow_parameters

the way it's called in

run_flow

(passing

flow

and

flow_run

) The last step returns the parameters that were specified in UI when the run was created.

inspect.signature(fn).parameters

(called in

parameters_to_args_kwargs

fn=flow.fn

) returns the actual parameters of the function, not args/kwargs.

07/19/2024, 6:54 PM

Indeed, I just ran

python -m prefect.engine FLOW_RUN_ID

on my machine and it succeeded..

07/19/2024, 7:13 PM

Alright, figured it out When

load_flow_from_entrypoint

cannot load a flow (due to a missing dependency for me) it returns a placeholder flow, which, according to a comment is supposed to reraise an exception when ran, but it never gets to since the confusing

SignatureMismatchError

is raised before that moment 🙂

👍 1

Xun Wang

07/19/2024, 7:17 PM

So it has nothing to do with the parameters passed in. I just didn’t find time to recheck the issue I reported. But will try to redeploy some flowswot 3.0rc once I have a chance. I suspect my flows were deployed long time ago with old ways which the latest >= 2.18 version running with cloud won’t be able to handle.

Nate

07/19/2024, 8:40 PM

hi all, this should be fixed on main and 2.x via https://github.com/PrefectHQ/prefect/pull/14669 and the corresponding PR for 3.x so once we release next, this change should take affect

Tom Matthews

07/25/2024, 9:36 PM

I'm still experiencing this issue on

2.17.1

, is that expected? Is there any recommendation for resolving this?

Nate

07/25/2024, 9:37 PM

hi @Tom Matthews - do you have an MRE for whats going wrong here? i dont totally remember the details here just yet

Nate

07/25/2024, 9:38 PM

ahh nevermind

Nate

07/25/2024, 9:38 PM

yes that is expected, you'd need to upgrade to the newer version of prefect 2.x that has the fix

Nate

07/25/2024, 9:39 PM

2.19.9 or above

Tom Matthews

07/25/2024, 9:49 PM

Perfect thanks, just bumping up to 2.19.9 now

Nate

07/25/2024, 9:50 PM

👍

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