Start allowing different merging types to be applied

After user data handling splits apart all the different
content types into there various mime messages it is
nice to be able to have each message specify how it should
be merged (mainly for cloud-config or cloud-archive) into
the single cloud config that is eventually used. This 
starts to add a plugable merging framework and the
needed components to activate said headers and merging.

1 files changed, 27 insertions, 22 deletions

diff --git a/cloudinit/handlers/__init__.py b/cloudinit/handlers/__init__.py
index 8d6dcd4d..bfccfd89 100644
--- a/cloudinit/handlers/__init__.py
+++ b/cloudinit/handlers/__init__.py
@@ -69,7 +69,6 @@ INCLUSION_SRCH = sorted(list(INCLUSION_TYPES_MAP.keys()),
 
 
 class Handler(object):
-
     __metaclass__ = abc.ABCMeta
 
     def __init__(self, frequency, version=2):
@@ -83,15 +82,12 @@ class Handler(object):
     def list_types(self):
         raise NotImplementedError()
 
-    def handle_part(self, data, ctype, filename, payload, frequency):
-        return self._handle_part(data, ctype, filename, payload, frequency)
-
     @abc.abstractmethod
-    def _handle_part(self, data, ctype, filename, payload, frequency):
+    def handle_part(self, *args, **kwargs):
         raise NotImplementedError()
 
 
-def run_part(mod, data, ctype, filename, payload, frequency):
+def run_part(mod, data, filename, payload, headers, frequency):
     mod_freq = mod.frequency
     if not (mod_freq == PER_ALWAYS or
             (frequency == PER_INSTANCE and mod_freq == PER_INSTANCE)):
@@ -102,19 +98,25 @@ def run_part(mod, data, ctype, filename, payload, frequency):
         mod_ver = int(mod_ver)
     except:
         mod_ver = 1
+    content_type = headers['Content-Type']
     try:
         LOG.debug("Calling handler %s (%s, %s, %s) with frequency %s",
-                  mod, ctype, filename, mod_ver, frequency)
-        if mod_ver >= 2:
+                  mod, content_type, filename, mod_ver, frequency)
+        if mod_ver == 3:
+            # Treat as v. 3 which does get a frequency + headers
+            mod.handle_part(data, content_type, filename,
+                            payload, frequency, headers)
+        elif mod_ver == 2:
             # Treat as v. 2 which does get a frequency
-            mod.handle_part(data, ctype, filename, payload, frequency)
+            mod.handle_part(data, content_type, filename,
+                            payload, frequency)
         else:
             # Treat as v. 1 which gets no frequency
-            mod.handle_part(data, ctype, filename, payload)
+            mod.handle_part(data, content_type, filename, payload)
     except:
         util.logexc(LOG, ("Failed calling handler %s (%s, %s, %s)"
                          " with frequency %s"),
-                    mod, ctype, filename,
+                    mod, content_type, filename,
                     mod_ver, frequency)
 
 
@@ -173,26 +175,27 @@ def _escape_string(text):
     return text
 
 
-def walker_callback(pdata, ctype, filename, payload):
-    if ctype in PART_CONTENT_TYPES:
-        walker_handle_handler(pdata, ctype, filename, payload)
+def walker_callback(data, filename, payload, headers):
+    content_type = headers['Content-Type']
+    if content_type in PART_CONTENT_TYPES:
+        walker_handle_handler(data, content_type, filename, payload)
         return
-    handlers = pdata['handlers']
-    if ctype in pdata['handlers']:
-        run_part(handlers[ctype], pdata['data'], ctype, filename,
-                 payload, pdata['frequency'])
+    handlers = data['handlers']
+    if content_type in handlers:
+        run_part(handlers[content_type], data['data'], filename,
+                 payload, headers, data['frequency'])
     elif payload:
         # Extract the first line or 24 bytes for displaying in the log
         start = _extract_first_or_bytes(payload, 24)
         details = "'%s...'" % (_escape_string(start))
         if ctype == NOT_MULTIPART_TYPE:
             LOG.warning("Unhandled non-multipart (%s) userdata: %s",
-                        ctype, details)
+                        content_type, details)
         else:
             LOG.warning("Unhandled unknown content-type (%s) userdata: %s",
-                        ctype, details)
+                        content_type, details)
     else:
-        LOG.debug("empty payload of type %s" % ctype)
+        LOG.debug("Empty payload of type %s", content_type)
 
 
 # Callback is a function that will be called with
@@ -212,7 +215,9 @@ def walk(msg, callback, data):
         if not filename:
             filename = PART_FN_TPL % (partnum)
 
-        callback(data, ctype, filename, part.get_payload(decode=True))
+        callback(data, ctype, filename,
+                 part.get_payload(decode=True),
+                 dict(part))
         partnum = partnum + 1