def _encode_message(cls, message):
"""
Encode a single message.
The magic number of a message is a format version number.
The only supported magic number right now is zero
Format
======
Message => Crc MagicByte Attributes Key Value
Crc => int32
MagicByte => int8
Attributes => int8
Key => bytes
Value => bytes
"""
if message.magic == 0:
msg = b''.join([
struct.pack('>BB', message.magic, message.attributes),
write_int_string(message.key),
write_int_string(message.value)
])
crc = crc32(msg)
msg = struct.pack('>I%ds' % len(msg), crc, msg)
else:
raise ProtocolError("Unexpected magic number: %d" % message.magic)
return msg
def _encode_message(cls, message):
"""
Encode a single message.
The magic number of a message is a format version number.
The only supported magic number right now is zero
Format
======
Message => Crc MagicByte Attributes Key Value
Crc => int32
MagicByte => int8
Attributes => int8
Key => bytes
Value => bytes
"""
if message.magic == 0:
msg = b''.join([
struct.pack('>BB', message.magic, message.attributes),
write_int_string(message.key),
write_int_string(message.value)
])
crc = crc32(msg)
msg = struct.pack('>I%ds' % len(msg), crc, msg)
else:
raise ProtocolError("Unexpected magic number: %d" % message.magic)
return msg
def encode_metadata_request(cls, client_id, correlation_id, topics=None,
payloads=None):
"""
Encode a MetadataRequest
Arguments:
client_id: string
correlation_id: int
topics: list of strings
"""
if payloads is None:
topics = [] if topics is None else topics
else:
topics = payloads
message = []
message.append(cls._encode_message_header(client_id, correlation_id,
KafkaProtocol.METADATA_KEY))
message.append(struct.pack('>i', len(topics)))
for topic in topics:
message.append(struct.pack('>h%ds' % len(topic), len(topic), topic))
msg = b''.join(message)
return write_int_string(msg)
def encode_metadata_request(cls, client_id, correlation_id, topics=None,
payloads=None):
"""
Encode a MetadataRequest
Arguments:
client_id: string
correlation_id: int
topics: list of strings
"""
if payloads is None:
topics = [] if topics is None else topics
else:
topics = payloads
message = []
message.append(cls._encode_message_header(client_id, correlation_id,
KafkaProtocol.METADATA_KEY))
message.append(struct.pack('>i', len(topics)))
for topic in topics:
message.append(struct.pack('>h%ds' % len(topic), len(topic), topic))
msg = b''.join(message)
return write_int_string(msg)
def encode_consumer_metadata_request(cls, client_id, correlation_id, payloads):
"""
Encode a ConsumerMetadataRequest
Arguments:
client_id: string
correlation_id: int
payloads: string (consumer group)
"""
message = []
message.append(cls._encode_message_header(client_id, correlation_id,
KafkaProtocol.CONSUMER_METADATA_KEY))
message.append(struct.pack('>h%ds' % len(payloads), len(payloads), payloads))
msg = b''.join(message)
return write_int_string(msg)
def encode_consumer_metadata_request(cls, client_id, correlation_id, payloads):
"""
Encode a ConsumerMetadataRequest
Arguments:
client_id: string
correlation_id: int
payloads: string (consumer group)
"""
message = []
message.append(cls._encode_message_header(client_id, correlation_id,
KafkaProtocol.CONSUMER_METADATA_KEY))
message.append(struct.pack('>h%ds' % len(payloads), len(payloads), payloads))
msg = b''.join(message)
return write_int_string(msg)