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.
14 from __future__ import print_function
20 class InvalidCommandError(Exception):
21 """Error that occurs when command class fails sanity checks."""
25 def CommandDecorator(command_name):
26 """Decorator that sanity checks and adds class to list of usable commands."""
28 def InnerCommandDecorator(original_class):
29 """"Inner Decorator that actually wraps the class."""
30 if not hasattr(original_class, '__doc__'):
31 raise InvalidCommandError('All handlers must have docstrings: %s' %
34 if not issubclass(original_class, CrosCommand):
35 raise InvalidCommandError('All Commands must derive from CrosCommand: '
36 '%s' % original_class)
38 _commands[command_name] = original_class
39 original_class.command_name = command_name
43 return InnerCommandDecorator
46 class CrosCommand(object):
47 """All CrosCommands must derive from this class.
49 This class provides the abstract interface for all Cros Commands. When
50 designing a new command, you must sub-class from this class and use the
51 CommandDecorator decorator. You must specify a class docstring as that will be
52 used as the usage for the sub-command.
54 In addition your command should implement AddParser which is passed in a
55 parser that you can add your own custom arguments. See argparse for more
58 # Indicates whether command stats should be uploaded for this command.
59 # Override to enable command stats uploading.
61 # We set the default timeout to 1 second, to prevent overly long waits for
62 # commands to complete. From manual tests, stat uploads usually take
63 # between 0.35s-0.45s in MTV.
64 upload_stats_timeout = 1
66 # Indicates whether command uses cache related commandline options.
67 use_caching_options = False
69 def __init__(self, options):
70 self.options = options
73 def AddParser(cls, parser):
74 """Add arguments for this command to the parser."""
75 parser.set_defaults(cros_class=cls)
78 """The command to run."""
79 raise NotImplementedError()