def _try_parse_data(self, node, piece):
"""Using the format in the given node, try to parse the given piece and re-acquire the data that created it
originally.
@return True on parse-success, False on failure.
@param node a `StringFormatNode` compatible node
@param piece a string which was previously returned by `iterate_consumption_candidates`
"""
try:
result = parse.parse(node.format_string(), piece, re_flags=0)
if result is None:
return False
if result.fixed:
raise ValueError("Format shouldn't have fixed arguments")
#end make assertion
except ValueError:
self.log.error("Ignored format as it could not be parsed: '%s'" % node.format_string(), exc_info=True)
return False
#end handle exceptions
# put keys into our data - its okay to have no keys, not all formats have them
if result.named:
kvstore = UnorderedKeyValueStoreModifier(self._parsed_data)
for nested_key, value in result.named.iteritems():
kvstore.set_value(nested_key, value)
#end for each key to store
# kvstore copies the data, therefore we have to get it back - its somewhat inefficient, but good
# enough for now. Could use the private API, _data(), to get a reference, but lets not go there.
self._parsed_data = kvstore.data()
#end fill data dict by keys
return True
def _apply_format(self, data, index=None):
"""@return a string which is the result of the substitution
@param data see the `format()` method
@param index a dict that will be used similarly to the `validate()` method of the `ValidatedElementNode`
to track format errors (which can only be cought when actually applying the format).
If None, these issues will not be recorded.
@return a new string with all substitutions applied successfully, or None string if there was insufficient data
or if we didn't have the format attribute.
And a (nested) data dictionary instance which contains all the data strings actually used. It will be empty
if there was no format.
"""
# determine if all named fields are actually available in data
invalid = (None, dict())
if not self._has_required_keys(data):
return invalid
# end
msg = None
try:
assert self.format_string(), "node '%s': Format should not be empty" % self.key()
res = self.format_string().format(**data)
# still here ? Store the data we actually used
kvmod = UnorderedKeyValueStoreModifier(dict())
kvprovider = RelaxedKeyValueStoreProvider(DictObject(data).to_dict(recursive=True))
for key in self.format_keys():
kvmod.set_value(key, kvprovider.value(key, dict()))
# end for each key
return res, kvmod.data()
except KeyError:
# apparently, someone used an alternate form, otherwise the _has_required_keys would have cought this
msg = "Use the dot-separated form to access members, not the dict one, in format '%s'" % self.format_string()
self.log.error(msg, exc_info=True)
except Exception:
# catch all - this is a serious issue though
msg = "Failed to apply format '%s'" % self.format_string()
self.log.error(msg, exc_info=True)
# end handle insufficient data for format
if msg and index:
index[self._to_fq_meta_key('format')] = msg
# end keep track of issues
return invalid
