opencv-python-headless installation bug

[lgvaz]

Bug

Trying to install the newest version of opencv-python-headless from pypi (4.4.0.46) gets stuck at:

Building wheel for opencv-python-headless (PEP 517) ...

Steps to reproduce

• Create a fresh environment
• run pip install opencv-python-headless

Or simply, check this colab notebook.

Full stack trace

Collecting opencv-python-headless
  Downloading https://files.pythonhosted.org/packages/07/e3/db18943862e08f444718952ef8cf80ea5b847fa20894227a22f3a5478575/opencv-python-headless-4.4.0.46.tar.gz (88.9MB)
     |████████████████████████████████| 88.9MB 108kB/s 
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Requirement already satisfied, skipping upgrade: numpy>=1.13.3 in /usr/local/lib/python3.6/dist-packages (from opencv-python-headless) (1.18.5)
Building wheels for collected packages: opencv-python-headless

Issue submission checklist

• This is not a generic OpenCV usage question (looking for help for coding, other usage questions, homework etc.)
• I have read the README of this repository and understand that this repository provides only an automated build toolchain for OpenCV Python packages (there is no actual OpenCV code here)
• The issue is related to the build scripts in this repository, to the pre-built binaries or is a feature request (such as "please enable this additional dependency")
• I'm using the latest version of opencv-python

[overclock98]

install !pip install opencv-python-headless==4.2.0.34

[skvark]

It's not stuck, just building from source since there are no pre-built wheels published yet. OpenCV is a very heavy C++ project and it takes 10 minutes even on 8-core CPUs to build it - on a Raspberry Pi it takes over 2 hours.

I hit the PyPI 20 GB project size limit during last release so it's going to take some time to clean up old releases and upload the new pre-built wheels. Please pin your dependencies, opencv-python-headless==4.4.0.44 is the same release as 4.4.0.46 which just adds Python 3.9 wheels.

[skvark]

Most of the wheels are now up. Windows builds still take some time to finish: https://ci.appveyor.com/project/skvark/opencv-python/history