Writing scap plugins

As of version 3.3.0, scap supports a rudimentary plugin API to allow users to build their own command line interfaces utilizing scap’s argument parser and rich set of utility methods.

Features

Scap provides a robust command line tool with infrastructure for easily defining and validating arguments. In addition to validation, scap will handle generating –help documentation for your commands and comprehensive bash autocompletion of complex argument values.

How it works

  1. At runtime, scap calls scap.plugins.find_plugins() which scans for any *.py files in a couple of standard locations:
  • the current project ./scap/plugins/*.py
  • the current user’s home directory ~/.scap/plugins/*.py
  1. Any matching files are loaded by scap.plugins.load_plugins() and the code evaluated in the context of the scap.plugins package namespace.
  2. Finally, any classes within a plugin module which inherit from scap.cli.Application are registered as scap subcommands (see scap.cli.subcommand()).

So, for example, if you have a file named scap/plugins/hello.py relative to either the current working directory or your user’s home directory, then scap will evaluate hello.py as a module named scap.plugins.hello. Now if you want it to actually work, then hopefully you have included a class inside hello.py, defined similarly to the following example.

Subcommand Example:

from scap import cli

@cli.command('hello', subcommands=True,
             help='prints "hello world" and exits',)
class HelloCommand(cli.Application):
    @cli.subcommand('world')
    def world_subcommand(extra_args):
        print('hello world')

See also