Optimizing buildouts with shared eggs and download caches¶
Most users should have this user-default configuration containing option settings that make Buildout work better:
[buildout] eggs-directory = ~/.buildout/eggs download-cache = ~/.buildout/download-cache abi-tag-eggs = true
You might be wondering why these settings aren’t the default, if they’re recommended for everyone. They probably should be the default, and perhaps will be in version 3 of buildout. Making them the default now might break existing buildouts.
Shared eggs directory¶
You can save a lot of time and disk space by sharing eggs between
buildouts. You can do this by setting the
as shown above. This will override the default value for this option
which puts eggs in the
eggs buildout subdirectory. By sharing
eggs, you can avoid reinstalling the same popular packages in each
and every buildout that uses them.
ABI tag eggs¶
If you use a shared eggs directory, it’s a good idea to set the
abi-tag-eggs option to
true. This causes eggs to be
segregated by ABI tag. This has two
- If you alternate between Python implementations (PyPy versus C Python) or between build configurations (normal versus debug), ABI tagging eggs will avoid mixing incompatible eggs.
- ABI tagging eggs makes Buildout run faster. Because ABI tags include Python version information, eggs for different Python versions are kept separate, causing the shared eggs directory for a given Python version to be smaller, making it faster to search for installed eggs.
When buildout installs distributions, it has to download them first.
download-cache option in your user-default
configuration causes the download to be
cached. This can be helpful when multiple installations might be
performed for a source distribution.
Some recipes download information. For example, a number of recipes download non-Python source archives and user configure, and make to install them. Most of these recipes can leverage a download cache to avoid downloading the same information over and over.