I've just upgraded from Python 2.6.1 to 2.6.4 on my development machine and upon starting a python script was presented with the following message:
Can't extract file(s) to egg cache
The following error occurred while trying to extract file(s) to the Python egg cache:
[Errno 13] Permission denied: '/var/www/.python-eggs'
The Python egg cache directory is currently set to:
/var/www/.python-eggs
Perhaps your account does not have write access to this directory? You can change the cache directory by setting the PYTHON_EGG_CACHE environment variable to point to an accessible directory.
There isn't anything in the python docs so I'm at a bit of a loss regarding best-practices on where to put this directory and what it's used for.
Can someone explain what the Python egg cache is?
Also, can you explain why/how it is different to the site-packages
directory Python uses to store eggs (as I understand it)?
A "Python egg" is a logical structure embodying the release of a specific version of a Python project, comprising its code, resources, and metadata. There are multiple formats that can be used to physically encode a Python egg, and others can be developed.
From my investigations it turns out that some eggs are packaged as zip files, and are saved as such in Python's site-packages
directory.
These zipped eggs need to be unzipped before they can be executed, so are expanded into the PYTHON_EGG_CACHE
directory which by default is ~/.python-eggs
(located in the user's home directory). If this doesn't exist it causes problems when trying to run applications.
There are a number of fixes:
.python-eggs
directory in the user's home directory and make it writable for the user./tmp/python-eggs
) and set the environment variable PYTHON_EGG_CACHE
to this directory.-Z
switch when using easy_install
to unzip the package when installing.If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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