1 # Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
2 # Use of this source code is governed by a BSD-style license that can be
3 # found in the LICENSE file.
5 """Module that contains meta-logic related to Cros Commands.
7 This module contains two important definitions used by all commands.
9 CrosCommand: The parent class of all cros commands.
10 CommandDecorator: Decorator that must be used to ensure that the command shows
11 up in _commands and is discoverable by cros.
18 class InvalidCommandError(Exception):
19 """Error that occurs when command class fails sanity checks."""
23 def CommandDecorator(command_name):
24 """Decorator that sanity checks and adds class to list of usable commands."""
26 def InnerCommandDecorator(original_class):
27 """"Inner Decorator that actually wraps the class."""
28 if not hasattr(original_class, '__doc__'):
29 raise InvalidCommandError('All handlers must have docstrings: %s' %
32 if not issubclass(original_class, CrosCommand):
33 raise InvalidCommandError('All Commands must derive from CrosCommand: '
34 '%s' % original_class)
36 _commands[command_name] = original_class
37 original_class.command_name = command_name
41 return InnerCommandDecorator
44 class CrosCommand(object):
45 """All CrosCommands must derive from this class.
47 This class provides the abstract interface for all Cros Commands. When
48 designing a new command, you must sub-class from this class and use the
49 CommandDecorator decorator. You must specify a class docstring as that will be
50 used as the usage for the sub-command.
52 In addition your command should implement AddParser which is passed in a
53 parser that you can add your own custom arguments. See argparse for more
56 # Indicates whether command stats should be uploaded for this command.
57 # Override to enable command stats uploading.
59 # We set the default timeout to 1 second, to prevent overly long waits for
60 # commands to complete. From manual tests, stat uploads usually take
61 # between 0.35s-0.45s in MTV.
62 upload_stats_timeout = 1
64 # Indicates whether command uses cache related commandline options.
65 use_caching_options = False
67 def __init__(self, options):
68 self.options = options
71 def AddParser(cls, parser):
72 """Add arguments for this command to the parser."""
73 parser.set_defaults(cros_class=cls)
76 """The command to run."""
77 raise NotImplementedError()