def get_key_reference(scope, name, user=None):
"""
Given a key name and user this method returns a new name (string ref)
to address the key value pair in the context of that user.
:param user: User to whom key belongs.
:type user: ``str``
:param name: Original name of the key.
:type name: ``str``
:rtype: ``str``
"""
if scope == SYSTEM_SCOPE or scope == FULL_SYSTEM_SCOPE:
return name
elif scope == USER_SCOPE or scope == FULL_USER_SCOPE:
if not user:
raise InvalidUserException(
"A valid user must be specified for user key ref."
)
return UserKeyReference(name=name, user=user).ref
else:
raise InvalidScopeException(
'Scope "%s" is not valid. Allowed scopes are %s.' % (scope, ALLOWED_SCOPES)
)
def _get(self, name):
# get the value for this key and save in value_cache
if self._key_prefix:
key = "%s.%s" % (self._key_prefix, name)
else:
key = UserKeyReference(name=name, user=self._user).ref
if self._prefix:
kvp_key = DATASTORE_KEY_SEPARATOR.join([self._prefix, key])
else:
kvp_key = key
value = self._get_kv(kvp_key)
self._value_cache[key] = value
# return a KeyValueLookup as response since the lookup may not be complete e.g. if
# the lookup is for 'key_base.key_value' it is likely that the calling code, e.g. Jinja,
# will expect to do a dictionary style lookup for key_base and key_value as subsequent
# calls. Saving the value in cache avoids extra DB calls.
return UserKeyValueLookup(
prefix=self._prefix,
user=self._user,
key_prefix=key,
cache=self._value_cache,
scope=self._scope,
)
