envelope.py 文件源码

def pack(self, message, ascii_encoded=False):
        """Packs a message for transport as described in y/cep342.

        Use :func:`unpack` to decode the packed message.

        Args:
            message (data_pipeline.message.Message): The message to pack
            ascii_decoded (Optional[bool]): Set to True if message is not valid ASCII

        Returns:
            bytes: Avro byte string prepended by magic envelope version byte

        The initial "magic byte" is meant to specify the envelope schema version.
        See y/cep342 for details.  In other words, the version number of the current
        schema is the null byte.  In the event we need to add additional envelope
        versions, we'll use this byte to identify it.

        In addition, the "magic byte" is used as a protocol to encode the serialized
        message in base64. See DATAPIPE-1350 for more detail. This option has been
        added because as of now, yelp_clog only supports sending valid ASCII strings.
        Producer/Consumer registration will make use of this to instead send base64
        encoded strings.
        """
        msg = bytes(0) + self._avro_string_writer.encode(message.avro_repr)

        if ascii_encoded:
            return self.ASCII_MAGIC_BYTE + base64.urlsafe_b64encode(msg)
        else:
            return msg