UnicodeEncodeError while deploying flows via code. #19083
Description
Bug summary
I have a script that deploys multiple flows into my Prefect server:
# Upload the flow file and configure deployments:
for flow_function, flow_file in FLOWS:
flow_function_name = flow_function.__name__
print(f"Deploying {flow_function_name} to process work pool")
# To run the file from Minio with a specific image:
flow_function.from_source(
source=flow_files_storage,
entrypoint=f"{flow_file}:{flow_function_name}",
).deploy(
name=f"{flow_function_name} process deployment",
work_pool_name=PROCESS_WORK_POOL,
job_variables={
"env": dict(os.environ),
},
)
Suddenly, after changing my environment, I get the following error when attempting to deploy the flows:
Looks like you're deploying to a process work pool. If you're creating a
deployment for local development, calling `.serve` on your flow is a great way
to get started. See the documentation for more information:
https://docs.prefect.io/latest/how-to-guides/deployments/run-flows-in-local-pro
cesses Set `ignore_warnings=True` to suppress this message.
Successfully created/updated all deployments!
Deployments
┌──────────────────────────────────────────────────────────────┬─────────┬────┐
│ Name │ Status │ D… │
├──────────────────────────────────────────────────────────────┼─────────┼────┤
│ Minio to Bronze Sync/sync_minio_to_bronze process deployment │ applied │ │
└──────────────────────────────────────────────────────────────┴─────────┴────┘
python-BaseException
Traceback (most recent call last):
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\utilities\asyncutils.py", line 207, in run_coro_as_sync
return call.result()
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\_internal\concurrency\calls.py", line 365, in result
return self.future.result(timeout=timeout)
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\_internal\concurrency\calls.py", line 192, in result
return self.__get_result()
File "C:\Users\User\AppData\Local\Programs\Python\Python39\lib\concurrent\futures\_base.py", line 390, in __get_result
raise self._exception
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\_internal\concurrency\calls.py", line 441, in _run_async
result = await coro
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\utilities\asyncutils.py", line 188, in coroutine_wrapper
return await task
File "C:\Users\User\AppData\Local\Programs\Python\Python39\lib\asyncio\futures.py", line 284, in __await__
yield self # This tells Task to wait for completion.
File "C:\Users\User\AppData\Local\Programs\Python\Python39\lib\asyncio\tasks.py", line 328, in __wakeup
future.result()
File "C:\Users\User\AppData\Local\Programs\Python\Python39\lib\asyncio\futures.py", line 201, in result
raise self._exception
File "C:\Users\User\AppData\Local\Programs\Python\Python39\lib\asyncio\tasks.py", line 256, in __step
result = coro.send(None)
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\utilities\asyncutils.py", line 341, in ctx_call
result = await async_fn(*args, **kwargs)
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\flows.py", line 1558, in deploy
deployment_ids = await deploy_coro
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\utilities\asyncutils.py", line 341, in ctx_call
result = await async_fn(*args, **kwargs)
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\prefect\deployments\runner.py", line 1323, in deploy
console.print(table)
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\rich\console.py", line 1740, in print
self._buffer.extend(new_segments)
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\rich\console.py", line 866, in __exit__
self._exit_buffer()
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\rich\console.py", line 824, in _exit_buffer
self._check_buffer()
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\rich\console.py", line 2033, in _check_buffer
self._write_buffer()
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\rich\console.py", line 2081, in _write_buffer
write(text)
File "C:\Projects\BullzAI\NewETLPilot\venv\lib\site-packages\win32\scripts\pywin32_postinstall.py", line 33, in write
tee_f.write(what)
File "C:\Users\User\AppData\Local\Programs\Python\Python39\lib\encodings\cp1252.py", line 19, in encode
return codecs.charmap_encode(input,self.errors,encoding_table)[0]
UnicodeEncodeError: 'charmap' codec can't encode characters in position 81-159: character maps to <undefined>
*** You may need to add PYTHONIOENCODING=utf-8 to your environment ***
I have attempted to debug the issue and see if there are any problematic characters in any of my files by placing a breakpoint and viewing the input value in the cp1252.py file in the encoding library:
class IncrementalEncoder(codecs.IncrementalEncoder):
def encode(self, input, final=False):
return codecs.charmap_encode(input,self.errors,encoding_table)[0]
The input value that caused the exception was actually the table that prefect generates:
Deployments
┌──────────────────────────────────────────────────────────────┬─────────┬────┐
│ Name │ Status │ D… │
├──────────────────────────────────────────────────────────────┼─────────┼────┤
│ Minio to Bronze Sync/sync_minio_to_bronze process deployment │ applied │ │
└──────────────────────────────────────────────────────────────┴─────────┴────┘
Version info
Version: 3.4.7
API version: 0.8.4
Python version: 3.9.7
Git commit: cd81d15a
Built: Thu, Jun 26, 2025 09:16 PM
OS/Arch: win32/AMD64
Profile: ephemeral
Server type: server
Pydantic version: 2.11.7
Integrations:
prefect-aws: 0.5.11
prefect-github: 0.3.1
Additional context
No response