[BUG] AsgiFunctionApp is missing BindingApi and SettingsApi mixins

[mortendaehli]

Investigative information

• Timestamp: 2024-02-05T08:28:51.887Z
• Core Tools version: 4.0.5455

Repro steps

1. Create Azure Functions Python V2 docker template
2. Create AsgiFunctionApp using FastAPI
3. Add any BindingApi functions such as queue_output
4. Run the application in Docker (need to install Core tools and run in verbose to get the actual Exception. Without it, it fails silently)

Expected behavior

I should be able to add BindingApi and SettingsApi such as queue output, function name, etc. to my application while running FastAPI.

Actual behavior

No functions are loaded when running in Docker.

If I add the Core Tools and run --verbose:

[2024-02-05T08:29:00.675Z] Worker failed to index functions
[2024-02-05T08:29:00.676Z] Result: Failure
[2024-02-05T08:29:00.677Z] Exception: AttributeError: 'AsgiFunctionApp' object has no attribute 'queue_output'
[2024-02-05T08:29:00.677Z] Stack:   File "/usr/lib/azure-functions-core-tools-4/workers/python/3.11/LINUX/X64/azure_functions_worker/dispatcher.py", line 345, in _handle__functions_metadata_request
[2024-02-05T08:29:00.677Z]     fx_metadata_results = self.index_functions(function_path)
[2024-02-05T08:29:00.677Z]                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[2024-02-05T08:29:00.677Z]   File "/usr/lib/azure-functions-core-tools-4/workers/python/3.11/LINUX/X64/azure_functions_worker/dispatcher.py", line 617, in index_functions
[2024-02-05T08:29:00.677Z]     indexed_functions = loader.index_function_app(function_path)
[2024-02-05T08:29:00.677Z]                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[2024-02-05T08:29:00.677Z]   File "/usr/lib/azure-functions-core-tools-4/workers/python/3.11/LINUX/X64/azure_functions_worker/utils/wrappers.py", line 44, in call
[2024-02-05T08:29:00.677Z]     return func(*args, **kwargs)
[2024-02-05T08:29:00.677Z]            ^^^^^^^^^^^^^^^^^^^^^
[2024-02-05T08:29:00.677Z]   File "/usr/lib/azure-functions-core-tools-4/workers/python/3.11/LINUX/X64/azure_functions_worker/loader.py", line 214, in index_function_app
[2024-02-05T08:29:00.677Z]     imported_module = importlib.import_module(module_name)
[2024-02-05T08:29:00.677Z]                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[2024-02-05T08:29:00.677Z]   File "/usr/local/lib/python3.11/importlib/__init__.py", line 126, in import_module
[2024-02-05T08:29:00.677Z]     return _bootstrap._gcd_import(name[level:], package, level)
[2024-02-05T08:29:00.677Z]            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[2024-02-05T08:29:00.677Z]   File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
[2024-02-05T08:29:00.677Z]   File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
[2024-02-05T08:29:00.677Z]   File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
[2024-02-05T08:29:00.677Z]   File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
[2024-02-05T08:29:00.677Z]   File "<frozen importlib._bootstrap_external>", line 940, in exec_module
[2024-02-05T08:29:00.677Z]   File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
[2024-02-05T08:29:00.677Z]   File "/home/site/wwwroot/function_app.py", line 35, in <module>
[2024-02-05T08:29:00.677Z]     ingestion.app_factory(app)
[2024-02-05T08:29:00.677Z]   File "/home/site/wwwroot/src/data_hub/ingestion.py", line 22, in app_factory
[2024-02-05T08:29:00.677Z]     @app.queue_output(arg_name="msg", queue_name="model-data-ingestion-queue", connection="AzureWebJobsStorage")  # type: ignore[misc]
[2024-02-05T08:29:00.677Z]      ^^^^^^^^^^^^^^^^
[2024-02-05T08:29:00.677Z] .
[2024-02-05T08:29:00.683Z] 0 functions found (Worker)
[2024-02-05T08:29:00.699Z] 0 functions loaded

Known workarounds

This monkey patch works:

class FastAPIFunctionApp(func.AsgiFunctionApp, func.BindingApi, func.SettingsApi):
    """
    Adding missing BindingApi and SettingsApi to the AsgiFunctionApp
    """
    pass

Contents of the requirements.txt file:

azure-functions
fastapi

Related information

• BindingApi in general
• SettingsApi in general