1. Add an importer function that will search for a given module in a set of search module 'prefixes'

   that also has a potential set of required attributes.
2. Use this new importer to find the distro class, the userdata handler modules, the config modules
   and the datasource modules, if none can be found error out accordingly.

1 files changed, 10 insertions, 13 deletions

diff --git a/cloudinit/distros/__init__.py b/cloudinit/distros/__init__.py
index 25a60c52..e0ef6ee0 100644
--- a/cloudinit/distros/__init__.py
+++ b/cloudinit/distros/__init__.py
@@ -144,16 +144,13 @@ class Distro(object):
             return False
 
 
-def fetch(distro_name, mods=(__name__, )):
-    mod = None
-    for m in mods:
-        mod_name = "%s.%s" % (m, distro_name)
-        try:
-            mod = importer.import_module(mod_name)
-        except ImportError:
-            pass
-    if not mod:
-        raise RuntimeError("No distribution found for distro %s"
-                           % (distro_name))
-    distro_cls = getattr(mod, 'Distro')
-    return distro_cls
+def fetch(name):
+    locs = importer.find_module(name,
+                                ['', __name__],
+                                ['Distro'])
+    if not locs:
+        raise ImportError("No distribution found for distro %s"
+                           % (name))
+    mod = importer.import_module(locs[0])
+    cls = getattr(mod, 'Distro')
+    return cls