handlers: Add fail_on_exception handler.

[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..29dc75631823ed79d5ecda18b99698d6dcacb782 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 +52,9 @@ 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
 
     def run(self, **kwargs):
         """
@@ -59,7 +76,32 @@ 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):
     """