The opening section shows the copyright statement, which should tip you off that this is an official plugin.

__description__ is a required variable.

__description__ = "plugin to create skeleton CherryPy applications"

It contains the description displayed when a user runs:

% coily --help

Usage: coily [command]
...
        --gen-cherrypy-app [name]       plugin to create skeleton CherryPy applications
        

Opening line defines create with two arguments.

def create(plugin_path, name):

The arguments allow both the plugin path to be fed along with the command-line argument that is filled in when the user runs the command:

% coily --gen-cherrypy-app [name]

It is important to realize that plugin_path is needed in case the plugin needs to refer to any files inside its installed directory. This is because plugins are not installed anywhere on the PYTHONPATH, but instead, in the user's home directory underneath .springpython.

This mechanism was chosen because it gives users an easy ability to pick which plugins they wish to use, without requiring system admin power. It also eliminates the need to deal with multiple versions of plugins being installed on your PYTHONPATH. This provides maximum flexibility which is needed in a development environment.

This plugin works by creating a directory in the user's current working directory, and putting all relevant files into it. The argument passed into the command-line is used as the name of an application, and the directory created has the same name.

    if not os.path.exists(name):
        print "Creating CherryPy skeleton app %s" % name
        os.makedirs(name)

However, if the directory already exists, it won't proceed.

    else:
        print "There is already something called %s. ABORT!" % name

This plugin then iterates over a list of filenames, which happen to match the names of files found in the plugin's directory. These are essentially template files, intended to be copied into the target directory. However, the files are not copied directly. Instead they are opened and read into memory.

        # Copy/transform the template files
        for file_name in ["cherrypy-app.py", "controller.py", "view.py", "app_context.py"]:
            input_file = open(plugin_path + "/" + file_name).read()

Then, the contents are scanned for key phrases, and substituted. In this case, the substitution is a variant of the name of the application being generated.

            # Iterate over a list of patterns, performing string substitution on the input file
            patterns_to_replace = [("name", name), ("properName", name[0].upper() + name[1:])]
            for pattern, replacement in patterns_to_replace:
                input_file = re.compile(r"\$\{%s}" % pattern).sub(replacement, input_file)

The substituted content is written to a new output file. In most cases, the original filename is also the target filename. However, the key file, cherrypy-app.py is renamed to the application's name.

            output_filename = name + "/" + file_name
            if file_name == "cherrypy-app.py":
                output_filename = name + "/" + name + ".py"

            app = open(output_filename, "w")
            app.write(input_file)
            app.close()

Finally, the images directory is recursively copied into the target directory.

        # Recursively copy other parts
        shutil.copytree(plugin_path + "/images", name + "/" + "images")