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Failed executing Azure App Function (Python) after publishing to Azure. 'No module named <n>'. Works locally

I have a python function that I've created as an Azure App Function. It works on my local machine fine, however fails with no descriptive error when executed after a successful publishing.

Originally, it failed with 500 internal server error due to:

Result: Failure
Exception: ModuleNotFoundError: No module named 'pandas'
Stack:   File "/root/.pyenv/versions/3.6.8/lib/python3.6/site-packages/azure/functions_worker/dispatcher.py", line 218, in _handle__function_load_request
    func_request.metadata.entry_point)
  File "/root/.pyenv/versions/3.6.8/lib/python3.6/site-packages/azure/functions_worker/loader.py", line 66, in load_function
    mod = importlib.import_module(fullmodname)
  File "/root/.pyenv/versions/3.6.8/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 941, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/site/wwwroot/generateGraph/__init__.py", line 2, in <module>
    import pandas as pd

I thought this was me not publishing with the --build-native-deps switch. So I republished with this switch: (.env) C:\Temp\python_function>func azure functionapp publish httpGenGraph --build-native-deps

And publishing was successful. Now, when I execute the Http Trigger, I get the same error again. Is there something I'm missing? I'm new to Python so it could be not understanding the packaging requirements or something. The function does work within my local virtual python environment.

Solution

  • Figured it out. I needed to pipe the output of pip freeze to the requirements.txt file. This allowed the packages to be properly referenced when publishing.

    For reference: 

    (.env) C:\Temp\python_function>pip freeze > requirements.txt

    Then:

    (.env) C:\Temp\python_function>func azure functionapp publish httpGenGraph --build-native-deps