pip install numpyused to take ages, and now it’s super fast thanks to piwheels.
The Python Package Index (PyPI) is a package repository for Python modules. Members of the Python community publish software and libraries in it as an easy method of distribution. If you’ve ever used
pip install, PyPI is the service that hosts the software you installed. You may have noticed that some installations can take a long time on the Raspberry Pi. That usually happens when modules have been implemented in C and require compilation.
Pip works by browsing PyPI for a wheel matching the user’s architecture — and if it doesn’t find one, it falls back to the source distribution (usually a tarball or zip of the source code). Then the user has to build it themselves, which can take a long time, or may require certain dependencies. And if pip can’t find a source distribution, the installation fails.
In order to solve this problem, I decided to build wheels of every package on PyPI. I wrote some tooling for automating the process and used a postgres database to monitor the status of builds and log the output. Using a Pi 3 in my living room, I attempted to build wheels of the latest version of all 100 000 packages on PyPI and to host them on a web server on the Pi. This took a total of ten days, and my proof-of-concept seemed to show that it generally worked and was likely to be useful! You could install packages directly from the server, and installations were really fast.
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