blob: ff664f85168b5ee25784610c1bec576896c824fc [file] [log] [blame]
# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Module that contains meta-logic related to Cros Commands.
This module contains two important definitions used by all commands.
CrosCommand: The parent class of all cros commands.
CommandDecorator: Decorator that must be used to ensure that the command shows
up in _commands and is discoverable by cros.
from __future__ import print_function
_commands = dict()
class InvalidCommandError(Exception):
"""Error that occurs when command class fails sanity checks."""
def CommandDecorator(command_name):
"""Decorator that sanity checks and adds class to list of usable commands."""
def InnerCommandDecorator(original_class):
""""Inner Decorator that actually wraps the class."""
if not hasattr(original_class, '__doc__'):
raise InvalidCommandError('All handlers must have docstrings: %s' %
if not issubclass(original_class, CrosCommand):
raise InvalidCommandError('All Commands must derive from CrosCommand: '
'%s' % original_class)
_commands[command_name] = original_class
original_class.command_name = command_name
return original_class
return InnerCommandDecorator
class CrosCommand(object):
"""All CrosCommands must derive from this class.
This class provides the abstract interface for all Cros Commands. When
designing a new command, you must sub-class from this class and use the
CommandDecorator decorator. You must specify a class docstring as that will be
used as the usage for the sub-command.
In addition your command should implement AddParser which is passed in a
parser that you can add your own custom arguments. See argparse for more
# Indicates whether command stats should be uploaded for this command.
# Override to enable command stats uploading.
upload_stats = False
# We set the default timeout to 1 second, to prevent overly long waits for
# commands to complete. From manual tests, stat uploads usually take
# between 0.35s-0.45s in MTV.
upload_stats_timeout = 1
# Indicates whether command uses cache related commandline options.
use_caching_options = False
def __init__(self, options):
self.options = options
def AddParser(cls, parser):
"""Add arguments for this command to the parser."""
def Run(self):
"""The command to run."""
raise NotImplementedError()