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Building Packages #

• A source distribution sdist is a build of a Python package that includes all the source code, and any relevant C/C++ exenstions
  • This is shipped in a tar.gz file
  • Includes .py files, C++, C files for binary modules which can then be used to recompile on any platform
  • When pip retrieves a source distrubtion, it first creates a wheel from it, then installs it
• bdist_* means built distribution
  • This includes .pyc files, .so, .dll, etc. and no setup.py
  • This package is specific to a platform (e.g. linux x86) and to the version of Python
  • From this archive you can just extract it into the relavant parts of your filesystem (e.g. packages) and it will will
• Built distributions are much faster than source distributions because the install doesn’t need to go through setup.py

Note:

• .pyc files are python files compiled to bytecode. After importing a module, Python will often build these .pyc files to make importing the module much faster the next tie

Wheels #

• A wheel is a standard PEP format, egg is not
• Wheels do not include .pyc files
  • Thus, when a wheel only contains .py files it can be “universal” and work on any platform
• Eggs are the older version of wheels
• To build a universal wheel (Python 2 and Python 3 compatible) you pass the universal flag to setup.py
  • e.g. python setup.py bdist_wheel --universal
  • This is a Pure Python wheel
• Non-universal wheels (the default) support one major version of Python
  • 1. If the code is pure Python (e.g. no compiled extensions - .pyc files), it will build a package compatible with the major Python version (e.g. Python 2 or 3)
    • python setup.py bdist_wheel
• Platform wheels only support one platform (e.g. Linux)
  • These will be automatically created if there are .pyc files
    • setup.py automatically determines when to build a platform wheel when running python setup.by bdist_wheel
• To install a wheel file you can just do pip install <file>.whl

Naming Convention #

e.g. mypackage-0.0.1-py3-none-any.whl

• Automatically created by the build process
• Broken down as follows:
  • <package_name>---<ABI_tag>-
  • So the above would translate as mypackage, version 0.0.1, for Python 3, no ABI requirements, any platform