Why few packages of python doesn't support in Azure Function V2?

Question

I'm trying to publish my app to azure function from visual studio code, and the following are my dependencies,

    pyodbc==4.0.26
pandas==0.25.0
numpy==1.16.4
azure-eventhub==1.3.1

and when I'm publishing my app I get the following error, ERROR: cannot install cryptography-2.7 dependency: binary dependencies without wheels are not supported. Use the --build-native-deps option to automatically build and configure the dependencies using a Docker container. More information at https://aka.ms/func-python-publish

Answer 1

This is a limitation of the way azure functions uses pip to download wheels. cryptography uploads an abi3 manylinux wheel, but this command can't successfully download it. For more information (and a workaround) see: https://github.com/Azure/azure-functions-core-tools/issues/1150

Answer 2

The link in the error message does answer your exact question:

If you're using a package that requires a compiler and does not support the installation of many linux-compatible wheels from PyPI, publishing to Azure will fail

If you ask for the "why was it designed in this way?" - that's a different question and out of scope for StackOverflow. You might want to try on the Functions Github