Complete initial cleanup for refactoring/rework.

Some of the cleanups were the following

1. Using standard (logged) utility functions for sub process work, writing, reading files, and other file system/operating system options
2. Having distrobutions impelement there own subclasses to handle system specifics (if applicable)
3. Having a cloud wrapper that provides just the functionality we want to expose (cloud.py)
4. Using a path class instead of globals for all cloud init paths (it is configured via config)
5. Removal of as much shared global state as possible (there should be none, minus a set of constants)
6. Other various cleanups that remove transforms/handlers/modules from reading/writing/chmoding there own files. 
 a. They should be using util functions to take advantage of the logging that is now enabled in those util functions (very useful for debugging)
7. Urls being read and checked from a single module that serves this and only this purpose (+1 for code organization)
8. Updates to log whenever a transform decides not to run
9. Ensure whenever a exception is thrown (and possibly captured) that the util.logexc function is called 
 a. For debugging, tracing this is important to not just drop them on the floor.
10. Code shuffling into utils.py where it makes sense (and where it could serve a benefit for other code now or in the future)

1 files changed, 29 insertions, 6 deletions

diff --git a/cloudinit/transforms/cc_foo.py b/cloudinit/transforms/cc_foo.py
index 35ec3fa7..8007f981 100644
--- a/cloudinit/transforms/cc_foo.py
+++ b/cloudinit/transforms/cc_foo.py
@@ -18,12 +18,35 @@
 #    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 cloudinit
-#import cloudinit.util as util
-from cloudinit.CloudConfig import per_instance
+from cloudinit.settings import PER_INSTANCE
 
-frequency = per_instance
+# Modules are expected to have the following attributes.
+# 1. A required 'handle' method which takes the following params.
+#    a) The name will not be this files name, but instead
+#    the name specified in configuration (which is the name
+#    which will be used to find this module).
+#    b) A configuration object that is the result of the merging
+#    of cloud configs configuration with legacy configuration
+#    as well as any datasource provided configuration
+#    c) A cloud object that can be used to access various
+#    datasource and paths for the given distro and data provided
+#    by the various datasource instance types. 
+#    d) A argument list that may or may not be empty to this module.
+#    Typically those are from module configuration where the module
+#    is defined with some extra configuration that will eventually
+#    be translated from yaml into arguments to this module.
+# 2. A optional 'frequency' that defines how often this module should be ran.
+#    Typically one of PER_INSTANCE, PER_ALWAYS, PER_ONCE. If not 
+#    provided PER_INSTANCE will be assumed. 
+#    See settings.py for these constants.
+# 3. A optional 'distros' array/set/tuple that defines the known distros
+#    this module will work with (if not all of them). This is used to write
+#    a warning out if a module is being ran on a untested distribution for
+#    informational purposes. If non existent all distros are assumed and 
+#    no warning occurs.
 
+frequency = settings.PER_INSTANCE
 
-def handle(_name, _cfg, _cloud, _log, _args):
-    print "hi"
+
+def handle(name, _cfg, _cloud, _log, _args):
+    print("Hi from %s" % (name))