yolk-acme example plugin
========================

The purpose of this plugin is to show which packages were installed via an 
external package manager or directly by distutils/setuptools.

This plugin example shows how to use the `add_column` method 
to add this information to the output of -l, -a, or -n.

To actually make this plugin work you will need to be able to determine if
a file was installed by your package manager.  An actual working plugin that
does this is the `yolk-portage` plugin included in the examples folder. It
determines if a file was installed by Gentoo's `portage` package manager by
using the program `qfile` available from app-portage/portage-utils.

You'll need to put the actual name of your package manager
here:

    class PackageManagerPlugin:
        name = "pkg-manager-name"

By doing that you have a new --pkg-manager-name option availabe to yolk.

Next, you'll need to return a string you want added to
the output if your package manager installed the package
or return "" if not.

    def package_manager_owns(self, dist):
       if your pkg manager owns file:
           return "(acme)"
       else:
           return ""


The text you return can be the name of the package manager
or the full package name your package manager used to install it,
for example.

Normal output of yolk -l looks like:

python-fchksum  - 1.7.1        - active
python-openid   - 1.2.0        - active
python-xlib     - 0.12         - active
pyvorbis        - 1.4          - active
rope            - 0.4          - active

With your plugin it may look like:

python-fchksum  - 1.7.1        - active (acme)
python-openid   - 1.2.0        - active (acme)
python-xlib     - 0.12         - active
pyvorbis        - 1.4          - active (acme)
rope            - 0.4          - active (acme)


Here is the code from Gentoo's yolk-portage plugin:

    def package_manager_owns(self, dist):
        """
        `dist` is a setuptools Distribution object passed by yolk
        when using the options -l, -n or -a

        Returns True if package manager installed the package
        Returns False if package manager did not install the package

        """

        #Find full path to a file in the Python package
        #If location is in site-packages dir, check for .egg-info file

        if dist.location.lower() == get_python_lib().lower():
            filename = os.path.join(dist.location, dist.egg_name() + ".egg-info")
        else:
            filename = dist.location

        #Determine if external package manager installed it

        status, output = getstatusoutput("/usr/bin/qfile -q %s" % filename)

        #status == 0 (file was installed by Gentoo Portage)
        #status == 256 (file was not installed by Gentoo Portage)

        if status == 0:
            return output.split()[0]
        else:
            return ""