'Retrieve JSON metadata from container metadata.
:type full_url: str
:param full_url: The full URL of the metadata service.
This should include the scheme as well, e.g
"http://localhost:123/foo"'

def retrieve_full_uri(self, full_url, headers=None):

    self._validate_allowed_url(full_url)
    return self._retrieve_credentials(full_url, headers)
