Distutils2 provides a way of extending its commands by the use of pre- and post- command hooks. The hooks are simple Python functions (or any callable objects) and are specified in the config file using their full qualified names. The pre-hooks are run after the command is finalized (its options are processed), but before it is run. The post-hooks are run after the command itself. Both types of hooks receive an instance of the command object.
Firstly, you need to make sure your hook is present in the path. This is usually done by dropping them to the same folder where setup.py file lives
# file: myhooks.py
def my_install_hook(install_cmd):
print "Oh la la! Someone is installing my project!"
Then, you need to point to it in your setup.cfg file, under the appropriate command section
[install]
pre-hook.project = myhooks.my_install_hook
The hooks defined in different config files (system-wide, user-wide and package-wide) do not override each other as long as they are specified with different aliases (additional names after the dot). The alias in the example above is project.