python - Installing OpenCV fails because it cannot find "skbuild"

Question

I have a docker image that I need to install openCV in it and from yesterday it started to fail because it cannot find the "skbuild" module:

Step 12/24 : RUN pip install opencv-python opencv-contrib-python
 ---> Running in a0f746a23aed
Collecting opencv-python
  Downloading https://files.pythonhosted.org/packages/77/f5/49f034f8d109efcf9b7e98fbc051878b83b2f02a1c73f92bbd37f317288e/opencv-python-4.4.0.42.tar.gz (88.9MB)
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-cciracwm/opencv-python/setup.py", line 9, in <module>
        import skbuild
    ModuleNotFoundError: No module named 'skbuild'

And on the host also I cannot find that module and pip search is either return nothing or returns a server error:

sudo pip3 search skbuild
WARNING: The directory '/home/ali/.cache/pip' or its parent directory is not owned or is not writable by the current user. The cache has been disabled. Check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
ERROR: Exception:
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/pip/_internal/cli/base_command.py", line 216, in _main
    status = self.run(options, args)
  File "/usr/local/lib/python3.6/dist-packages/pip/_internal/commands/search.py", line 60, in run
    pypi_hits = self.search(query, options)
  File "/usr/local/lib/python3.6/dist-packages/pip/_internal/commands/search.py", line 80, in search
    hits = pypi.search({'name': query, 'summary': query}, 'or')
  File "/usr/lib/python3.6/xmlrpc/client.py", line 1112, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib/python3.6/xmlrpc/client.py", line 1452, in __request
    verbose=self.__verbose
  File "/usr/local/lib/python3.6/dist-packages/pip/_internal/network/xmlrpc.py", line 45, in request
    return self.parse_response(response.raw)
  File "/usr/lib/python3.6/xmlrpc/client.py", line 1342, in parse_response
    return u.close()
  File "/usr/lib/python3.6/xmlrpc/client.py", line 656, in close
    raise Fault(**self._stack[0])
xmlrpc.client.Fault: <Fault -32403: 'server error; service unavailable'>

Is this because their server has some problems or it is related to my pip?

Update

I tried it on different python and pip versions, python versions 3.6 and 3.7 and pip version 19.12 and 20.2.2 and 9.0.1 (the one inside image).

Update 2

I added pip install scikit-build one step before opencv installation but I get another error related to cmake:

Step 12/25 : RUN pip install scikit-build
 ---> Running in afe0c5c0fca0
Collecting scikit-build
  Downloading https://files.pythonhosted.org/packages/78/c9/7c2c7397ea64e36ebb292446896edcdecbb8c1aa6b9a1a32f6f67984c3df/scikit_build-0.11.1-py2.py3-none-any.whl (72kB)
Collecting packaging (from scikit-build)
  Downloading https://files.pythonhosted.org/packages/46/19/c5ab91b1b05cfe63cccd5cfc971db9214c6dd6ced54e33c30d5af1d2bc43/packaging-20.4-py2.py3-none-any.whl
Requirement already satisfied: wheel>=0.29.0 in /usr/lib/python3/dist-packages (from scikit-build)
Collecting distro (from scikit-build)
  Downloading https://files.pythonhosted.org/packages/25/b7/b3c4270a11414cb22c6352ebc7a83aaa3712043be29daa05018fd5a5c956/distro-1.5.0-py2.py3-none-any.whl
Requirement already satisfied: setuptools>=28.0.0; python_version >= "3" in /usr/lib/python3/dist-packages (from scikit-build)
Requirement already satisfied: six in /usr/lib/python3/dist-packages (from packaging->scikit-build)
Collecting pyparsing>=2.0.2 (from packaging->scikit-build)
  Downloading https://files.pythonhosted.org/packages/8a/bb/488841f56197b13700afd5658fc279a2025a39e22449b7cf29864669b15d/pyparsing-2.4.7-py2.py3-none-any.whl (67kB)
Installing collected packages: pyparsing, packaging, distro, scikit-build
Successfully installed distro-1.5.0 packaging-20.4 pyparsing-2.4.7 scikit-build-0.11.1
Removing intermediate container afe0c5c0fca0
 ---> 533658ddf26d
Step 13/25 : RUN pip install opencv-python opencv-contrib-python
 ---> Running in 0f2c03bc042a
Collecting opencv-python
  Downloading https://files.pythonhosted.org/packages/77/f5/49f034f8d109efcf9b7e98fbc051878b83b2f02a1c73f92bbd37f317288e/opencv-python-4.4.0.42.tar.gz (88.9MB)
Collecting opencv-contrib-python
  Downloading https://files.pythonhosted.org/packages/48/98/05bd8e00c71b66c4e7847cc051cac404191d904df58b51a7dcc3767ff747/opencv_contrib_python-4.2.0.34-cp37-cp37m-manylinux1_x86_64.whl (34.2MB)
Collecting numpy>=1.14.5 (from opencv-python)
  Downloading https://files.pythonhosted.org/packages/3d/d1/90cd7e0b27ee86d77f5386d38b74520486100286d50772377791b6ef22ff/numpy-1.19.1-cp37-cp37m-manylinux1_x86_64.whl (13.4MB)
Building wheels for collected packages: opencv-python
  Running setup.py bdist_wheel for opencv-python: started
  Running setup.py bdist_wheel for opencv-python: finished with status 'error'
  Complete output from command /usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-w49xv99a/opencv-python/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('
', '
');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /tmp/tmpycj03zlwpip-wheel- --python-tag cp37:
  /usr/lib/python3.7/distutils/dist.py:274: UserWarning: Unknown distribution option: 'long_description_content_type'
    warnings.warn(msg)
  Traceback (most recent call last):
    File "/usr/local/lib/python3.7/dist-packages/skbuild/setuptools_wrap.py", line 560, in setup
      cmkr = cmaker.CMaker(cmake_executable)
    File "/usr/local/lib/python3.7/dist-packages/skbuild/cmaker.py", line 95, in __init__
      self.cmake_version = get_cmake_version(self.cmake_executable)
    File "/usr/local/lib/python3.7/dist-packages/skbuild/cmaker.py", line 82, in get_cmake_version
      "Problem with the CMake installation, aborting build. CMake executable is %s" % cmake_executable)
  
  Problem with the CMake installation, aborting build. CMake executable is cmake
  
  ----------------------------------------
  Failed building wheel for opencv-python
  Running setup.py clean for opencv-python
Failed to build opencv-python
Installing collected packages: numpy, opencv-python, opencv-contrib-python
  Found existing installation: numpy 1.13.3
    Not uninstalling numpy at /usr/lib/python3/dist-packages, outside environment /usr
  Running setup.py install for opencv-python: started
    Running setup.py install for opencv-python: finished with status 'error'
    Complete output from command /usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-w49xv99a/opencv-python/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('
', '
');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-maky1uyw-record/install-record.txt --single-version-externally-managed --compile:
    /usr/lib/python3.7/distutils/dist.py:274: UserWarning: Unknown distribution option: 'long_description_content_type'
      warnings.warn(msg)
    Traceback (most recent call last):
      File "/usr/local/lib/python3.7/dist-packages/skbuild/setuptools_wrap.py", line 560, in setup
        cmkr = cmaker.CMaker(cmake_executable)
      File "/usr/local/lib/python3.7/dist-packages/skbuild/cmaker.py", line 95, in __init__
        self.cmake_version = get_cmake_version(self.cmake_executable)
      File "/usr/local/lib/python3.7/dist-packages/skbuild/cmaker.py", line 82, in get_cmake_version
        "Problem with the CMake installation, aborting build. CMake executable is %s" % cmake_executable)
    
    Problem with the CMake installation, aborting build. CMake executable is cmake

Answer 1

If you read the opencv-python package FAQ in PyPI, it clearly provides an answer for this specific issue: you must run pip install --upgrade pip. Check pip version afterwards with pip -V.

This is because your pip is too old to understand the new manylinux2014 package format and tries to compile from source. That will also fail because pip is too old to understand how to use pyproject.toml to install build dependencies such as scikit-build.

Another issue I'm spotting is that you install both opencv-python and opencv-contrib-python. You should not do this. It's also explained in the PyPI page of the packages. Most likely you should be using just opencv-contrib-python-headless package since you are using Docker and I assume you do not use the GUI functionalities of OpenCV.