Instead of having the cloud pass large references to its constructor, this has been reduced to actual objects.

Added a get template filename helper which can be used to locate template files for various handlers/transforms.
Ensured that the config that we give back out is copied, so that it can't be modified by any 'malicous' handlers/transforms.
Added helper method cycle_logging that can resetup logging, this is mainly used by the rsyslog transform.

cloudinit/cloud.py

@@ -20,6 +20,9 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import copy
+import os
+
 from cloudinit import distros
 from cloudinit import helpers
 from cloudinit import log as logging
@@ -28,18 +31,40 @@ LOG = logging.getLogger(__name__)
 
 
 class Cloud(object):
-    def __init__(self, datasource, paths, cfg):
+    def __init__(self, datasource, paths, cfg, distro, runners):
         self.datasource = datasource
         self.paths = paths
-        self.cfg = cfg
-        self.distro = distros.fetch(cfg, self)
-        self.runners = helpers.Runners(paths)
+        self.distro = distro
+        self._cfg = cfg
+        self._runners = runners
+
+    # If a transform manipulates logging or logging services
+    # it is typically useful to cause the logging to be
+    # setup again.
+    def cycle_logging(self):
+        logging.setupLogging(self.cfg)
+
+    @property
+    def cfg(self):
+        # Ensure that not indirectly modified
+        return copy.deepcopy(self._cfg)
 
     def run(self, name, functor, args, freq=None, clear_on_fail=False):
-        return self.runners.run(name, functor, args, freq, clear_on_fail)
+        return self._runners.run(name, functor, args, freq, clear_on_fail)
 
+    def get_template_filename(self, name):
+        fn = self.paths.template_tpl % (name)
+        if not os.path.isfile(fn):
+            LOG.warn("No template found at %s for template named %s", fn, name)
+            return None
+        return fn
+
+    # The rest of thes are just useful proxies
     def get_userdata(self):
         return self.datasource.get_userdata()
+    
+    def get_instance_id(self):
+        return self.datasource.get_instance_id()
 
     def get_public_ssh_keys(self):
         return self.datasource.get_public_ssh_keys()
@@ -47,7 +72,7 @@ class Cloud(object):
     def get_locale(self):
         return self.datasource.get_locale()
 
-    def get_mirror(self):
+    def get_local_mirror(self):
         return self.datasource.get_local_mirror()
 
     def get_hostname(self, fqdn=False):