Fixed merging capabilities.

Instead of previously having merging which was not backwards compatible
with the 0.7.1 and prior methods this patch works to ensure said backwards
compatible while at the same time making the new merging functionality
work in a more customizable manner.

1 files changed, 30 insertions, 14 deletions

diff --git a/cloudinit/handlers/cloud_config.py b/cloudinit/handlers/cloud_config.py
index d30d6338..c97ca3e8 100644
--- a/cloudinit/handlers/cloud_config.py
+++ b/cloudinit/handlers/cloud_config.py
@@ -30,7 +30,25 @@ from cloudinit.settings import (PER_ALWAYS)
 LOG = logging.getLogger(__name__)
 
 MERGE_HEADER = 'Merge-Type'
-DEF_MERGERS = mergers.default_mergers()
+
+# Due to the way the loading of yaml configuration was done previously,
+# where previously each cloud config part was appended to a larger yaml
+# file and then finally that file was loaded as one big yaml file we need
+# to mimic that behavior by altering the default strategy to be replacing
+# keys of prior merges.
+#
+#
+# For example
+# #file 1
+# a: 3
+# #file 2
+# a: 22
+# #combined file (comments not included)
+# a: 3
+# a: 22
+#
+# This gets loaded into yaml with final result {'a': 22}
+DEF_MERGERS = mergers.string_extract_mergers('dict(replace)+list()+str()')
 
 
 class CloudConfigPartHandler(handlers.Handler):
@@ -39,7 +57,6 @@ class CloudConfigPartHandler(handlers.Handler):
         self.cloud_buf = None
         self.cloud_fn = paths.get_ipath("cloud_config")
         self.file_names = []
-        self.mergers = [DEF_MERGERS]
 
     def list_types(self):
         return [
@@ -54,6 +71,8 @@ class CloudConfigPartHandler(handlers.Handler):
         if self.file_names:
             file_lines.append("# from %s files" % (len(self.file_names)))
             for fn in self.file_names:
+                if not fn:
+                    fn = '?'
                 file_lines.append("# %s" % (fn))
             file_lines.append("")
         if self.cloud_buf is not None:
@@ -86,26 +105,20 @@ class CloudConfigPartHandler(handlers.Handler):
         all_mergers.extend(mergers_header)
         if not all_mergers:
             all_mergers = DEF_MERGERS
-        return all_mergers
+        return (payload_yaml, all_mergers)
 
     def _merge_part(self, payload, headers):
-        next_mergers = self._extract_mergers(payload, headers)
-        # Use the merger list from the last call, since it is the one
-        # that will be defining how to merge with the next payload.
-        curr_mergers = list(self.mergers[-1])
-        LOG.debug("Merging by applying %s", curr_mergers)
-        self.mergers.append(next_mergers)
-        merger = mergers.construct(curr_mergers)
+        (payload_yaml, my_mergers) = self._extract_mergers(payload, headers)
+        LOG.debug("Merging by applying %s", my_mergers)
+        merger = mergers.construct(my_mergers)
         if self.cloud_buf is None:
             # First time through, merge with an empty dict...
             self.cloud_buf = {}
-        self.cloud_buf = merger.merge(self.cloud_buf,
-                                      util.load_yaml(payload))
+        self.cloud_buf = merger.merge(self.cloud_buf, payload_yaml)
 
     def _reset(self):
         self.file_names = []
         self.cloud_buf = None
-        self.mergers = [DEF_MERGERS]
 
     def handle_part(self, _data, ctype, filename,  # pylint: disable=W0221
                     payload, _frequency, headers):  # pylint: disable=W0613
@@ -118,7 +131,10 @@ class CloudConfigPartHandler(handlers.Handler):
             return
         try:
             self._merge_part(payload, headers)
-            self.file_names.append(filename)
+            # Ensure filename is ok to store
+            for i in ("\n", "\r", "\t"):
+                filename = filename.replace(i, " ")
+            self.file_names.append(filename.strip())
         except:
             util.logexc(LOG, "Failed at merging in cloud config part from %s",
                         filename)