diff options
Diffstat (limited to 'cloudinit/mergers')
| -rw-r--r-- | cloudinit/mergers/__init__.py | 59 | ||||
| -rw-r--r-- | cloudinit/mergers/dict.py | 11 | ||||
| -rw-r--r-- | cloudinit/mergers/list.py | 21 | ||||
| -rw-r--r-- | cloudinit/mergers/str.py | 5 |
4 files changed, 76 insertions, 20 deletions
diff --git a/cloudinit/mergers/__init__.py b/cloudinit/mergers/__init__.py index 20658edc..4a112165 100644 --- a/cloudinit/mergers/__init__.py +++ b/cloudinit/mergers/__init__.py @@ -34,6 +34,13 @@ class UnknownMerger(object): def _handle_unknown(self, meth_wanted, value, merge_with): return value + # This merging will attempt to look for a '_on_X' method + # in our own object for a given object Y with type X, + # if found it will be called to perform the merge of a source + # object and a object to merge_with. + # + # If not found the merge will be given to a '_handle_unknown' + # function which can decide what to do wit the 2 values. def merge(self, source, merge_with): type_name = util.obj_name(source) type_name = type_name.lower() @@ -56,6 +63,11 @@ class LookupMerger(UnknownMerger): else: self._lookups = lookups + # For items which can not be merged by the parent this object + # will lookup in a internally maintained set of objects and + # find which one of those objects can perform the merge. If + # any of the contained objects have the needed method, they + # will be called to perform the merge. def _handle_unknown(self, meth_wanted, value, merge_with): meth = None for merger in self._lookups: @@ -70,8 +82,33 @@ class LookupMerger(UnknownMerger): return meth(value, merge_with) -def _extract_merger_names(merge_how): - names = [] +def dict_extract_mergers(config): + parsed_mergers = [] + raw_mergers = config.get('merger_how') + if raw_mergers is None: + raw_mergers = config.get('merge_type') + if raw_mergers is None: + return parsed_mergers + if isinstance(raw_mergers, (str, basestring)): + return string_extract_mergers(raw_mergers) + for m in raw_mergers: + if isinstance(m, (dict)): + name = m['name'] + name = name.replace("-", "_").strip() + opts = m['settings'] + else: + name = m[0] + if len(m) >= 2: + opts = m[1:] + else: + opts = [] + if name: + parsed_mergers.append((name, opts)) + return parsed_mergers + + +def string_extract_mergers(merge_how): + parsed_mergers = [] for m_name in merge_how.split("+"): # Canonicalize the name (so that it can be found # even when users alter it in various ways) @@ -79,20 +116,20 @@ def _extract_merger_names(merge_how): m_name = m_name.replace("-", "_") if not m_name: continue - names.append(m_name) - return names - - -def construct(merge_how): - mergers_to_be = [] - for name in _extract_merger_names(merge_how): - match = NAME_MTCH.match(name) + match = NAME_MTCH.match(m_name) if not match: - msg = "Matcher identifer '%s' is not in the right format" % (name) + msg = "Matcher identifer '%s' is not in the right format" % (m_name) raise ValueError(msg) (m_name, m_ops) = match.groups() m_ops = m_ops.strip().split(",") m_ops = [m.strip().lower() for m in m_ops if m.strip()] + parsed_mergers.append((m_name, m_ops)) + return parsed_mergers + + +def construct(parsed_mergers): + mergers_to_be = [] + for (m_name, m_ops) in parsed_mergers: merger_locs = importer.find_module(m_name, [__name__], ['Merger']) diff --git a/cloudinit/mergers/dict.py b/cloudinit/mergers/dict.py index bc392afa..45a7d3a5 100644 --- a/cloudinit/mergers/dict.py +++ b/cloudinit/mergers/dict.py @@ -22,6 +22,17 @@ class Merger(object): self._merger = merger self._overwrite = 'overwrite' in opts + # This merging algorithm will attempt to merge with + # another dictionary, on encountering any other type of object + # it will not merge with said object, but will instead return + # the original value + # + # On encountering a dictionary, it will create a new dictionary + # composed of the original and the one to merge with, if 'overwrite' + # is enabled then keys that exist in the original will be overwritten + # by keys in the one to merge with (and associated values). Otherwise + # if not in overwrite mode the 2 conflicting keys themselves will + # be merged. def _on_dict(self, value, merge_with): if not isinstance(merge_with, (dict)): return value diff --git a/cloudinit/mergers/list.py b/cloudinit/mergers/list.py index a848b8d6..a56ff007 100644 --- a/cloudinit/mergers/list.py +++ b/cloudinit/mergers/list.py @@ -26,21 +26,24 @@ class Merger(object): def _on_tuple(self, value, merge_with): return self._on_list(list(value), merge_with) + # On encountering a list or tuple type this action will be applied + # a new list will be returned, if the value to merge with is itself + # a list and we have been told to 'extend', then the value here will + # be extended with the other list. If in 'extend' mode then we will + # attempt to merge instead, which means that values from the list + # to merge with will replace values in te original list (they will + # also be merged recursively). + # + # If the value to merge with is not a list, and we are set to discared + # then no modifications will take place, otherwise we will just append + # the value to merge with onto the end of our own list. def _on_list(self, value, merge_with): new_value = list(value) if isinstance(merge_with, (tuple, list)): if self._extend: new_value.extend(merge_with) else: - # Merge instead - for m_v in merge_with: - m_am = 0 - for (i, o_v) in enumerate(new_value): - if m_v == o_v: - new_value[i] = self._merger.merge(o_v, m_v) - m_am += 1 - if m_am == 0: - new_value.append(m_v) + return new_value else: if not self._discard_non: new_value.append(merge_with) diff --git a/cloudinit/mergers/str.py b/cloudinit/mergers/str.py index 14bc46ec..f1534c5b 100644 --- a/cloudinit/mergers/str.py +++ b/cloudinit/mergers/str.py @@ -21,9 +21,14 @@ class Merger(object): def __init__(self, merger, opts): self._append = 'append' in opts + # On encountering a unicode object to merge value with + # we will for now just proxy into the string method to let it handle it. def _on_unicode(self, value, merge_with): return self._on_str(value, merge_with) + # On encountering a string object to merge with we will + # perform the following action, if appending we will + # merge them together, otherwise we will just return value. def _on_str(self, value, merge_with): if not self._append: return value |