handlers: Make create_action pass any kwargs to the constructor.

[matthijs/projects/backupninja.git] / src / lib / backupninja / handlers / __init__.py

diff --git a/src/lib/backupninja/handlers/__init__.py b/src/lib/backupninja/handlers/__init__.py
index 72b30179a3a0017f9bfe3447b60d9e5d5365922a..50abb41307c9078444200c86c731e9de284a1cb7 100644 (file)
--- a/src/lib/backupninja/handlers/__init__.py
+++ b/src/lib/backupninja/handlers/__init__.py
@@ -19,11 +19,25 @@
 
 """ Action superclass with common functionality """
 
-import sys
+import sys, ConfigParser
 import logging as log
 
 from backupninja import config
 
+def fail_on_exception(f):
+    """
+    This is a decorator meant for methods on the Action class. It
+    catches any exceptions thrown, sets the failed attribute to True and
+    rethrows the exception.
+    """
+    def inner(self, *args, **kwargs):
+        try:
+            f(self, *args, **kwargs)
+        except:
+            self.failed = True
+            raise
+    return inner
+
 class Action(object):
     """
     Subclasses of Action represent handlers for various action types.
@@ -38,6 +52,13 @@ class Action(object):
         # See backupninja.config.load_config for the structure of this
         # value.
         self.default_config = {}
+        # Assume we'll run succesfully. If anything fails in the
+        # meanwhile, set this to True.
+        self.failed = False
+        # A logger object for this action. In the future, this might
+        # become a specific logger, that includes the action name and
+        # type.
+        self.log = log
 
     def run(self, **kwargs):
         """
@@ -59,12 +80,38 @@ class Action(object):
         """
         self.conf = config.load_config(filename, self.default_config)
 
-        
+    def get_config_optional(self, section, option):
+        """
+        Returns the value of the given option. If the option was not set
+        (and no default was set in self.default_config), return None.
+
+        This is a convenience wrapper for ConfigParser.get(), since that
+        throws an exception on unset options.
+        """
+        try:
+            return self.conf.get(section, option)
+        except ConfigParser.NoOptionError:
+            return None
+
+    def get_config_mandatory(self, section, option):
+        """
+        Returns the value of the given option. If the option was not set
+        (and no default was set in self.default_config), raises a
+        backupninja.config.ConfigError.
+
+        This is a convenience wrapper for ConfigParser.get(), since that
+        has a very generic exception message on unknown options.
+        """
+        try:
+            return self.conf.get(section, option)
+        except ConfigParser.NoOptionError:
+            raise config.ConfigError("Option '%s' in section '%s' is mandatory, please configure it" % (option, section))
 
-def create_action(ty):
+def create_action(ty, **kwargs):
     """
     Create a new (subclass of) Action object for an action with the
-    given type.
+    given type. Any extra keyword arguments are passed to the
+    constructor.
 
     If the handler class for this type cannot be loaded, an exception is
     thrown.
@@ -91,7 +138,7 @@ def create_action(ty):
                           % (module.__file__))
 
     # Call the "handler" function to create the actual action
-    action = module.handler()
+    action = module.handler(**kwargs)
    
     # Check if the handler returned is really a subclass of Action
     if not isinstance(action, Action):