2 # Backupninja python reimplementation, based on original backupninja program
4 # Copyright (C) 2010 Matthijs Kooijman <matthijs@stdin.nl>
6 # This program is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 2 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful,
12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 # GNU General Public License for more details.
16 # You should have received a copy of the GNU General Public License along
17 # with this program; if not, write to the Free Software Foundation, Inc.,
18 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20 """ Action superclass with common functionality """
22 import sys, ConfigParser
25 from backupninja import config
27 def fail_on_exception(f):
29 This is a decorator meant for methods on the Action class. It
30 catches any exceptions thrown, sets the failed attribute to True and
31 rethrows the exception.
33 def inner(self, *args, **kwargs):
35 f(self, *args, **kwargs)
43 Subclasses of Action represent handlers for various action types.
44 This class is called Action instead of Handler, since even though the
45 classes could be referred to as handlers, the instances of this
46 class are really actions (i.e., it represents a specific action,
47 which is a combination of a action type and a specific action
51 # Subclasses should overwrite this with their default config
52 # See backupninja.config.load_config for the structure of this
54 self.default_config = {}
55 # Assume we'll run succesfully. If anything fails in the
56 # meanwhile, set this to True.
58 # A logger object for this action. In the future, this might
59 # become a specific logger, that includes the action name and
63 def run(self, **kwargs):
65 Run this action for a single target. Override this method
70 def finish(self, **kwargs):
72 Called when all targets have been processed. Can be overridden
77 def load_config(self, filename):
79 Load the configuration for this action from the given filename.
81 self.conf = config.load_config(filename, self.default_config)
83 def get_config_optional(self, section, option):
85 Returns the value of the given option. If the option was not set
86 (and no default was set in self.default_config), return None.
88 This is a convenience wrapper for ConfigParser.get(), since that
89 throws an exception on unset options.
92 return self.conf.get(section, option)
93 except ConfigParser.NoOptionError:
96 def get_config_mandatory(self, section, option):
98 Returns the value of the given option. If the option was not set
99 (and no default was set in self.default_config), raises a
100 backupninja.config.ConfigError.
102 This is a convenience wrapper for ConfigParser.get(), since that
103 has a very generic exception message on unknown options.
106 return self.conf.get(section, option)
107 except ConfigParser.NoOptionError:
108 raise config.ConfigError("Option '%s' in section '%s' is mandatory, please configure it" % (option, section))
110 def create_action(ty, **kwargs):
112 Create a new (subclass of) Action object for an action with the
113 given type. Any extra keyword arguments are passed to the
116 If the handler class for this type cannot be loaded, an exception is
119 modname = 'backupninja.handlers.%s' % ty
120 # Load the handler if it is not loaded yet
121 if not modname in sys.modules:
122 log.debug('Loading handler for type "%s"', ty)
124 __import__(modname, globals(), locals(), [])
125 except ImportError, e:
126 # Add some extra info, since the default exception does not
127 # show the full module name.
128 raise ImportError('Cannot load module %s: %s' % (modname, e))
129 log.debug('Loaded handler for type "%s" from "%s"', ty, sys.modules[modname].__file__)
130 # Get the module from the module table
131 module = sys.modules[modname]
133 # Check that the module has a "handler" top level function, which
134 # should create a new Action object.
135 if not hasattr(module, 'handler'):
136 raise ImportError('%s is not valid: it '
137 'does not have a "handler" top level function.'
140 # Call the "handler" function to create the actual action
141 action = module.handler(**kwargs)
143 # Check if the handler returned is really a subclass of Action
144 if not isinstance(action, Action):
145 raise TypeError('%s is not valid, %s.handler did not return a '
146 'subclass of backupninja.handlers.Handler.'
147 % (module.__file__, modname))