Failing to install on Python3.8

[elfsonix]

Expected behaviour:

I want to install OpenCv for python3.8 on RaspberryPi.

Actual behaviour:

Installation fails with message:

 Collecting opencv-python
   Using cached opencv-python-4.4.0.44.tar.gz (88.9 MB)
   Installing build dependencies ... error
   ERROR: Command errored out with exit status 1:
    command: /usr/local/bin/python3.8 /usr/local/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-g177ilu2/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- setuptools wheel scikit-build cmake pip 'numpy==1.11.3; python_version=='"'"'3.5'"'"'' 'numpy==1.13.3; python_version=='"'"'3.6'"'"'' 'numpy==1.14.5; python_version=='"'"'3.7'"'"'' 'numpy==1.17.3; python_version>='"'"'3.8'"'"''
        cwd: None
   Complete output (22 lines):
   Ignoring numpy: markers 'python_version == "3.5"' don't match your environment
   Ignoring numpy: markers 'python_version == "3.6"' don't match your environment
   Ignoring numpy: markers 'python_version == "3.7"' don't match your environment
   Collecting setuptools
     Using cached setuptools-50.3.0-py3-none-any.whl (785 kB)
   Collecting wheel
     Using cached wheel-0.35.1-py2.py3-none-any.whl (33 kB)
   Collecting scikit-build
     Using cached scikit_build-0.11.1-py2.py3-none-any.whl (72 kB)
   Collecting cmake
     Using cached cmake-3.18.2.post1.tar.gz (28 kB)
       ERROR: Command errored out with exit status 1:
        command: /usr/local/bin/python3.8 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-1wr5nb2g/cmake/setup.py'"'"'; __file__='"'"'/tmp/pip-install-1wr5nb2g/cmake/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-dhutnjw4
            cwd: /tmp/pip-install-1wr5nb2g/cmake/
       Complete output (5 lines):
       Traceback (most recent call last):
         File "<string>", line 1, in <module>
         File "/tmp/pip-install-1wr5nb2g/cmake/setup.py", line 7, in <module>
           from skbuild import setup
       ModuleNotFoundError: No module named 'skbuild'
       ----------------------------------------
   ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
   ----------------------------------------
 ERROR: Command errored out with exit status 1: /usr/local/bin/python3.8 /usr/local/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-g177ilu2/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- setuptools wheel scikit-build cmake pip 'numpy==1.11.3; python_version=='"'"'3.5'"'"'' 'numpy==1.13.3; python_version=='"'"'3.6'"'"'' 'numpy==1.14.5; python_version=='"'"'3.7'"'"'' 'numpy==1.17.3; python_version>='"'"'3.8'"'"'' Check the logs for full command output.

Steps to reproduce:

operating system: RaspberryPi OS (32-bit) (https://www.raspberrypi.org/downloads/raspberry-pi-os/)
I am using the newest pip version (20.2.3) and command "python3.8 -m pip install opencv-python" (I also have python 3.7 installed, it works fine with 3.7 but I need to work with 3.8)

How can I fix this?

[skvark]

This project does not support ARM platforms due to various issues. You're seeing one of them, and it's caused by the cmake dependency:

File "/tmp/pip-install-1wr5nb2g/cmake/setup.py", line 7, in <module>
-------------------------------------^^^^

cmake has issues with ARM systems. See this issue for more info: scikit-build/cmake-python-distributions#103

Python 3.7 works because PiWheels provides a pre-built packages for that version (Python 3.8 is not supported): https://www.piwheels.org/project/opencv-python/

arm64 support tracking issue for opencv-python (also blocked by cmake issues): #366

Your options are:

• Use Python 3.7 and wait for a fix to the cmake issue
• Build OpenCV by hand (without the toolchain provided by this repository): https://docs.opencv.org/master/d2/de6/tutorial_py_setup_in_ubuntu.html