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Apache License
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APPENDIX: How to apply the Apache License to your work.
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75
README.md
Normal file
75
README.md
Normal file
@@ -0,0 +1,75 @@
|
|||||||
|
# Kakfa Python client
|
||||||
|
|
||||||
|
This module provides low-level protocol support Apache Kafka. It implements the five basic request types (and their responses): Produce, Fetch, MultiFetch, MultiProduce, and Offsets.
|
||||||
|
|
||||||
|
Compatible with Apache Kafka 0.7x.
|
||||||
|
|
||||||
|
# License
|
||||||
|
|
||||||
|
Copyright 2012, David Arthur under Apache License, v2.0. See `LICENSE`
|
||||||
|
|
||||||
|
# Usage
|
||||||
|
|
||||||
|
## Send a message to a topic
|
||||||
|
|
||||||
|
You need to specify the topic and partition
|
||||||
|
|
||||||
|
kafka = KafkaClient("localhost", 9092)
|
||||||
|
kafka.send_messages_simple("my-topic", 0, "some message")
|
||||||
|
kafka.close()
|
||||||
|
|
||||||
|
## Send several messages to a topic
|
||||||
|
|
||||||
|
Same as before, just add more arguments to `send_simple`
|
||||||
|
|
||||||
|
kafka = KafkaClient("localhost", 9092)
|
||||||
|
kafka.send_messages_simple("my-topic", 0, "some message", "another message", "and another")
|
||||||
|
kafka.close()
|
||||||
|
|
||||||
|
## Recieve some messages from a topic
|
||||||
|
|
||||||
|
Supply `get_message_set` with a `FetchRequest`, get back the messages and new `FetchRequest`
|
||||||
|
|
||||||
|
kafka = KafkaClient("localhost", 9092)
|
||||||
|
req = FetchRequest("my-topic", 0, 0, 1024*1024)
|
||||||
|
(messages, req1) = kafka.get_message_set(req)
|
||||||
|
kafka.close()
|
||||||
|
|
||||||
|
The returned `FetchRequest` includes the offset of the next message. This makes
|
||||||
|
paging through the queue very simple.
|
||||||
|
|
||||||
|
## Send multiple messages to multiple topics
|
||||||
|
|
||||||
|
For this we use the `send_multi_message_set` method along with `ProduceRequest` objects.
|
||||||
|
|
||||||
|
kafka = KafkaClient("localhost", 9092)
|
||||||
|
req1 = ProduceRequest("my-topic-1", 0, [
|
||||||
|
create_message_from_string("message one"),
|
||||||
|
create_message_from_string("message two")
|
||||||
|
])
|
||||||
|
req2 = ProduceRequest("my-topic-2", 0, [
|
||||||
|
create_message_from_string("nachricht ein"),
|
||||||
|
create_message_from_string("nachricht zwei")
|
||||||
|
])
|
||||||
|
kafka.sent_multi_message_set([req1, req1])
|
||||||
|
kafka.close()
|
||||||
|
|
||||||
|
## Iterate through all messages from an offset
|
||||||
|
|
||||||
|
The `iter_messages` method will make the underlying calls to `get_message_set`
|
||||||
|
to provide a generator that returns every message available.
|
||||||
|
|
||||||
|
kafka = KafkaClient("localhost", 9092)
|
||||||
|
for msg in kafka.iter_messages(FetchRequest("my-topic", 0, 0, 1024*1024)):
|
||||||
|
print(msg.payload)
|
||||||
|
kafka.close()
|
||||||
|
|
||||||
|
An optional `auto` argument will control auto-paging through results
|
||||||
|
|
||||||
|
kafka = KafkaClient("localhost", 9092)
|
||||||
|
for msg in kafka.iter_messages(FetchRequest("my-topic", 0, 0, 1024*1024), False):
|
||||||
|
print(msg.payload)
|
||||||
|
kafka.close()
|
||||||
|
|
||||||
|
This will only iterate through messages in the first byte range of
|
||||||
|
(0, 1024\*1024)
|
29
example.py
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29
example.py
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|
|||||||
|
import logging
|
||||||
|
|
||||||
|
from kafka import KafkaClient, FetchRequest, ProduceRequest
|
||||||
|
from kafka import create_message_from_string
|
||||||
|
|
||||||
|
def produce_example(kafka):
|
||||||
|
message = create_message_from_string("test")
|
||||||
|
request = ProduceRequest("my-topic", 0, [message])
|
||||||
|
print("Sending %s" % str(request))
|
||||||
|
kafka.send_message_set(request)
|
||||||
|
|
||||||
|
def consume_example(kafka):
|
||||||
|
request = FetchRequest("my-topic", 0, 0, 64)
|
||||||
|
print("Sending %s" % str(request))
|
||||||
|
(messages, nextRequest) = kafka.get_message_set(request)
|
||||||
|
print("Got %d messages:" % len(messages))
|
||||||
|
for message in messages:
|
||||||
|
print("\t%s" % message.payload)
|
||||||
|
print("Next request %s" % str(nextRequest))
|
||||||
|
|
||||||
|
def main():
|
||||||
|
kafka = KafkaClient("localhost", 9092)
|
||||||
|
produce_example(kafka)
|
||||||
|
consume_example(kafka)
|
||||||
|
|
||||||
|
|
||||||
|
if __name__ == "__main__":
|
||||||
|
logging.basicConfig(level=logging.DEBUG)
|
||||||
|
main()
|
475
kafka.py
Normal file
475
kafka.py
Normal file
@@ -0,0 +1,475 @@
|
|||||||
|
from collections import namedtuple
|
||||||
|
import logging
|
||||||
|
import select
|
||||||
|
import socket
|
||||||
|
import struct
|
||||||
|
import zlib
|
||||||
|
|
||||||
|
log = logging.getLogger("org.apache.kafka")
|
||||||
|
|
||||||
|
def length_prefix_message(msg):
|
||||||
|
"""
|
||||||
|
Prefix a message with it's length as an int
|
||||||
|
"""
|
||||||
|
return struct.pack('>i', len(msg)) + msg
|
||||||
|
|
||||||
|
|
||||||
|
def create_message_from_string(payload):
|
||||||
|
return Message(1, 0, zlib.crc32(payload), payload)
|
||||||
|
|
||||||
|
error_codes = {
|
||||||
|
-1: "UnknownError",
|
||||||
|
0: None,
|
||||||
|
1: "OffsetOutOfRange",
|
||||||
|
2: "InvalidMessage",
|
||||||
|
3: "WrongPartition",
|
||||||
|
4: "InvalidFetchSize"
|
||||||
|
}
|
||||||
|
|
||||||
|
class KafkaException(Exception):
|
||||||
|
def __init__(self, errorType):
|
||||||
|
self.errorType = errorType
|
||||||
|
def __str__(self):
|
||||||
|
return str(errorType)
|
||||||
|
|
||||||
|
|
||||||
|
Message = namedtuple("Message", ["magic", "attributes", "crc", "payload"])
|
||||||
|
FetchRequest = namedtuple("FetchRequest", ["topic", "partition", "offset", "size"])
|
||||||
|
ProduceRequest = namedtuple("ProduceRequest", ["topic", "partition", "messages"])
|
||||||
|
OffsetRequest = namedtuple("OffsetRequest", ["topic", "partition", "time", "maxOffsets"])
|
||||||
|
|
||||||
|
class KafkaClient(object):
|
||||||
|
"""
|
||||||
|
Request Structure
|
||||||
|
=================
|
||||||
|
|
||||||
|
<Request> ::= <len> <request-key> <payload>
|
||||||
|
<len> ::= <int32>
|
||||||
|
<request-key> ::= 0 | 1 | 2 | 3 | 4
|
||||||
|
<payload> ::= <ProduceRequest> | <FetchRequest> | <MultiFetchRequest> | <MultiProduceRequest> | <OffsetRequest>
|
||||||
|
|
||||||
|
Response Structure
|
||||||
|
==================
|
||||||
|
|
||||||
|
<Response> ::= <len> <err> <payload>
|
||||||
|
<len> ::= <int32>
|
||||||
|
<err> ::= -1 | 0 | 1 | 2 | 3 | 4
|
||||||
|
<payload> ::= <ProduceResponse> | <FetchResponse> | <MultiFetchResponse> | <MultiProduceResponse> | <OffsetResponse>
|
||||||
|
|
||||||
|
Messages are big-endian byte order
|
||||||
|
"""
|
||||||
|
|
||||||
|
PRODUCE_KEY = 0
|
||||||
|
FETCH_KEY = 1
|
||||||
|
MULTIFETCH_KEY = 2
|
||||||
|
MULTIPRODUCE_KEY = 3
|
||||||
|
OFFSET_KEY = 4
|
||||||
|
|
||||||
|
def __init__(self, host, port):
|
||||||
|
self.host = host
|
||||||
|
self.port = port
|
||||||
|
self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
|
||||||
|
self._sock.connect((host, port))
|
||||||
|
log.debug("Connected to %s on %d", host, port)
|
||||||
|
|
||||||
|
######################
|
||||||
|
# Protocol Stuff #
|
||||||
|
######################
|
||||||
|
|
||||||
|
def _consume_response_iter(self):
|
||||||
|
"""
|
||||||
|
This method handles the response header and error messages. It
|
||||||
|
then returns an iterator for the chunks of the response
|
||||||
|
"""
|
||||||
|
log.debug("Handling response from Kafka")
|
||||||
|
# Header
|
||||||
|
resp = self._sock.recv(6)
|
||||||
|
if resp == "":
|
||||||
|
raise Exception("Got no response from Kafka")
|
||||||
|
(size, err) = struct.unpack('>iH', resp)
|
||||||
|
|
||||||
|
log.debug("About to read %d bytes from Kafka", size-2)
|
||||||
|
# Handle error
|
||||||
|
error = error_codes.get(err)
|
||||||
|
if error is not None:
|
||||||
|
raise KafkaException(error)
|
||||||
|
|
||||||
|
# Response iterator
|
||||||
|
total = 0
|
||||||
|
while total < (size-2):
|
||||||
|
resp = self._sock.recv(1024)
|
||||||
|
log.debug("Read %d bytes from Kafka", len(resp))
|
||||||
|
if resp == "":
|
||||||
|
raise Exception("Underflow")
|
||||||
|
total += len(resp)
|
||||||
|
yield resp
|
||||||
|
|
||||||
|
def _consume_response(self):
|
||||||
|
"""
|
||||||
|
Fully consumer the response iterator
|
||||||
|
"""
|
||||||
|
data = ""
|
||||||
|
for chunk in self._consume_response_iter():
|
||||||
|
data += chunk
|
||||||
|
return data
|
||||||
|
|
||||||
|
|
||||||
|
def create_message(self, message):
|
||||||
|
"""
|
||||||
|
Create a Message from a Message tuple
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
message: Message
|
||||||
|
|
||||||
|
Wire Format
|
||||||
|
===========
|
||||||
|
<Message> ::= <Message-0> | <Message-1>
|
||||||
|
<Message-0> ::= <N> 0 <header-0> <payload>
|
||||||
|
<Message-1> ::= <N> 1 <header-1> <payload>
|
||||||
|
<N> ::= <int32>
|
||||||
|
<header-0> ::= <crc>
|
||||||
|
<header-1> ::= <attributes><crc>
|
||||||
|
<crc> ::= <int32>
|
||||||
|
<payload> ::= <bytes>
|
||||||
|
<attributes> ::= <int8>
|
||||||
|
|
||||||
|
The crc is a crc32 checksum of the message payload. The attributes are bitmask
|
||||||
|
used for indicating the compression algorithm.
|
||||||
|
"""
|
||||||
|
if message.magic == 0:
|
||||||
|
return struct.pack('>Bi%ds' % len(message.payload),
|
||||||
|
message.magic, message.crc, message.payload)
|
||||||
|
elif message.magic == 1:
|
||||||
|
return struct.pack('>BBi%ds' % len(message.payload),
|
||||||
|
message.magic, message.attributes, message.crc, message.payload)
|
||||||
|
else:
|
||||||
|
raise Exception("Unknown message version: %d" % message.magic)
|
||||||
|
|
||||||
|
def create_message_set(self, messages):
|
||||||
|
message_set = ""
|
||||||
|
for message in messages:
|
||||||
|
encoded_message = self.create_message(message)
|
||||||
|
message_set += length_prefix_message(encoded_message)
|
||||||
|
return message_set
|
||||||
|
|
||||||
|
def create_produce_request(self, produceRequest):
|
||||||
|
"""
|
||||||
|
Create a ProduceRequest
|
||||||
|
|
||||||
|
Wire Format
|
||||||
|
===========
|
||||||
|
<ProduceRequest> ::= <request-key> <topic> <partition> <len> <MessageSet>
|
||||||
|
<request-key> ::= 0
|
||||||
|
<topic> ::= <topic-length><string>
|
||||||
|
<topic-length> ::= <int16>
|
||||||
|
<partition> ::= <int32>
|
||||||
|
<len> ::= <int32>
|
||||||
|
|
||||||
|
The request-key (0) is encoded as a short (int16). len is the length of the proceeding MessageSet
|
||||||
|
"""
|
||||||
|
(topic, partition, messages) = produceRequest
|
||||||
|
message_set = self.create_message_set(messages)
|
||||||
|
req = struct.pack('>HH%dsii%ds' % (len(topic), len(message_set)),
|
||||||
|
KafkaClient.PRODUCE_KEY, len(topic), topic, partition, len(message_set), message_set)
|
||||||
|
return req
|
||||||
|
|
||||||
|
def create_multi_produce_request(self, produceRequests):
|
||||||
|
req = struct.pack('>HH', KafkaClient.MULTIPRODUCE_KEY, len(produceRequests))
|
||||||
|
for (topic, partition, messages) in produceRequests:
|
||||||
|
message_set = self.create_message_set(messages)
|
||||||
|
req += struct.pack('>H%dsii%ds' % (len(topic), len(message_set)),
|
||||||
|
len(topic), topic, partition, len(message_set), message_set)
|
||||||
|
return req
|
||||||
|
|
||||||
|
def create_fetch_request(self, fetchRequest):
|
||||||
|
"""
|
||||||
|
Create a FetchRequest message
|
||||||
|
|
||||||
|
Wire Format
|
||||||
|
===========
|
||||||
|
<FetchRequest> ::= <request-key> <topic> <partition> <offset> <size>
|
||||||
|
<request-key> ::= 1
|
||||||
|
<topic> ::= <topic-length><string>
|
||||||
|
<topic-length> ::= <int16>
|
||||||
|
<partition> ::= <int32>
|
||||||
|
<offset> ::= <int64>
|
||||||
|
<size> ::= <int32>
|
||||||
|
|
||||||
|
The request-key (1) is encoded as a short (int16).
|
||||||
|
"""
|
||||||
|
(topic, partition, offset, size) = fetchRequest
|
||||||
|
req = struct.pack('>HH%dsiqi' % len(topic),
|
||||||
|
KafkaClient.FETCH_KEY, len(topic), topic, partition, offset, size)
|
||||||
|
return req
|
||||||
|
|
||||||
|
def create_multi_fetch_request(self, fetchRequests):
|
||||||
|
"""
|
||||||
|
Create the MultiFetchRequest message from a list of FetchRequest objects
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
fetchRequests: list of FetchRequest
|
||||||
|
|
||||||
|
Returns
|
||||||
|
=======
|
||||||
|
req: bytes, The message to send to Kafka
|
||||||
|
|
||||||
|
Wire Format
|
||||||
|
===========
|
||||||
|
<MultiFetchRequest> ::= <request-key> <num> [ <FetchRequests> ]
|
||||||
|
<request-key> ::= 2
|
||||||
|
<num> ::= <int16>
|
||||||
|
<FetchRequests> ::= <FetchRequest> [ <FetchRequests> ]
|
||||||
|
<FetchRequest> ::= <topic> <partition> <offset> <size>
|
||||||
|
<topic> ::= <topic-length><string>
|
||||||
|
<topic-length> ::= <int16>
|
||||||
|
<partition> ::= <int32>
|
||||||
|
<offset> ::= <int64>
|
||||||
|
<size> ::= <int32>
|
||||||
|
|
||||||
|
The request-key (2) is encoded as a short (int16).
|
||||||
|
"""
|
||||||
|
req = struct.pack('>HH', KafkaClient.MULTIFETCH_KEY, len(fetchRequests))
|
||||||
|
for (topic, partition, offset, size) in fetchRequests:
|
||||||
|
req += struct.pack('>H%dsiqi' % len(topic), len(topic), topic, partition, offset, size)
|
||||||
|
return req
|
||||||
|
|
||||||
|
def create_offset_request(self, offsetRequest):
|
||||||
|
"""
|
||||||
|
Create an OffsetRequest message
|
||||||
|
|
||||||
|
Wire Format
|
||||||
|
===========
|
||||||
|
<OffsetRequest> ::= <request-key> <topic> <partition> <time> <max-offsets>
|
||||||
|
<request-key> ::= 4
|
||||||
|
<topic> ::= <topic-length><string>
|
||||||
|
<topic-length> ::= <int16>
|
||||||
|
<partition> ::= <int32>
|
||||||
|
<time> ::= <epoch>
|
||||||
|
<epoch> ::= <int64>
|
||||||
|
<max-offsets> ::= <int32>
|
||||||
|
|
||||||
|
The request-key (4) is encoded as a short (int16).
|
||||||
|
"""
|
||||||
|
(topic, partition, offset, maxOffsets) = offsetRequest
|
||||||
|
req = struct.pack('>HH%dsiqi' % len(topic), KafkaClient.OFFSET_KEY, len(topic), topic, partition, offset, maxOffsets)
|
||||||
|
return req
|
||||||
|
|
||||||
|
def read_message_set(self, data):
|
||||||
|
"""
|
||||||
|
Read a MessageSet
|
||||||
|
|
||||||
|
Wire Format
|
||||||
|
===========
|
||||||
|
<MessageSet> ::= <len> <Message> [ <MessageSet> ]
|
||||||
|
<len> ::= <int32>
|
||||||
|
|
||||||
|
len is the length of the proceeding Message
|
||||||
|
"""
|
||||||
|
|
||||||
|
# Read the MessageSet
|
||||||
|
cur = 0
|
||||||
|
msgs = []
|
||||||
|
size = len(data)
|
||||||
|
while cur < size:
|
||||||
|
if (cur + 5) > size:
|
||||||
|
# Underflow for the Header
|
||||||
|
if len(msgs) == 0:
|
||||||
|
raise Exception("Message underflow. Did not request enough bytes to consume a single message")
|
||||||
|
else:
|
||||||
|
log.debug("Not enough data to read header of next message")
|
||||||
|
break
|
||||||
|
# Read a Message header (length, magic byte)
|
||||||
|
(N, magic) = struct.unpack('>iB', data[cur:(cur+5)])
|
||||||
|
|
||||||
|
if (cur + N + 4) > size:
|
||||||
|
# Underflow for this Message
|
||||||
|
log.debug("Not enough data to read next message")
|
||||||
|
break
|
||||||
|
cur += 5
|
||||||
|
|
||||||
|
if magic == 0: # v0 Message
|
||||||
|
# Read crc; check the crc; append the message
|
||||||
|
(crc,) = struct.unpack('>i', data[cur:(cur+4)])
|
||||||
|
cur += 4
|
||||||
|
payload = data[cur:(cur+N-5)]
|
||||||
|
assert zlib.crc32(payload) == crc
|
||||||
|
cur += (N-5)
|
||||||
|
log.debug("Got v0 Message, %d bytes", len(payload))
|
||||||
|
msgs.append(Message(magic, None, crc, payload))
|
||||||
|
elif magic == 1: # v1 Message
|
||||||
|
# Read attributes, crc; check the crc; append the message
|
||||||
|
(att, crc) = struct.unpack('>Bi', data[cur:(cur+5)])
|
||||||
|
cur += 5
|
||||||
|
payload = data[cur:(cur+N-6)]
|
||||||
|
assert zlib.crc32(payload) == crc
|
||||||
|
cur += (N-6)
|
||||||
|
log.debug("Got v1 Message, %d bytes", len(payload))
|
||||||
|
msgs.append(Message(magic, att, crc, payload))
|
||||||
|
|
||||||
|
# Return the retrieved messages and the cursor position
|
||||||
|
return (msgs, cur)
|
||||||
|
|
||||||
|
#########################
|
||||||
|
# Advanced User API #
|
||||||
|
#########################
|
||||||
|
|
||||||
|
def send_message_set(self, produceRequest):
|
||||||
|
"""
|
||||||
|
Send a ProduceRequest
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
produceRequest: ProduceRequest
|
||||||
|
"""
|
||||||
|
req = length_prefix_message(self.create_produce_request(produceRequest))
|
||||||
|
log.debug("Sending %d bytes to Kafka", len(req))
|
||||||
|
self._sock.send(req)
|
||||||
|
|
||||||
|
def send_multi_message_set(self, produceRequests):
|
||||||
|
"""
|
||||||
|
Send a MultiProduceRequest
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
produceRequests: list of ProduceRequest
|
||||||
|
"""
|
||||||
|
req = length_prefix_message(self.create_multi_produce_request(produceRequests))
|
||||||
|
log.debug("Sending %d bytes to Kafka", len(req))
|
||||||
|
self._sock.send(req)
|
||||||
|
|
||||||
|
def get_message_set(self, fetchRequest):
|
||||||
|
"""
|
||||||
|
Send a FetchRequest and return the Messages
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
fetchRequest: FetchRequest named tuple
|
||||||
|
|
||||||
|
Returns
|
||||||
|
=======
|
||||||
|
A tuple of (list(Message), FetchRequest). This FetchRequest will have the offset
|
||||||
|
starting at the next message.
|
||||||
|
"""
|
||||||
|
|
||||||
|
req = length_prefix_message(self.create_fetch_request(fetchRequest))
|
||||||
|
log.debug("Sending %d bytes to Kafka", len(req))
|
||||||
|
self._sock.send(req)
|
||||||
|
data = self._consume_response()
|
||||||
|
(messages, read) = self.read_message_set(data)
|
||||||
|
|
||||||
|
# Return the retrieved messages and the next FetchRequest
|
||||||
|
return (messages, FetchRequest(fetchRequest.topic, fetchRequest.partition, (fetchRequest.offset + read), fetchRequest.size))
|
||||||
|
|
||||||
|
def get_multi_message_set(self, fetchRequests):
|
||||||
|
"""
|
||||||
|
Send several FetchRequests in a single pipelined request.
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
fetchRequests: list of FetchRequest
|
||||||
|
|
||||||
|
Returns
|
||||||
|
=======
|
||||||
|
list of tuples of (list(Message), FetchRequest). This FetchRequest will have the offset
|
||||||
|
starting at the next message.
|
||||||
|
|
||||||
|
Wire Format
|
||||||
|
===========
|
||||||
|
<MultiFetchResponse> ::= <MultiMessageSet>
|
||||||
|
<MultiMessageSet> ::= <MultiMessage> [ <MultiMessageSet> ]
|
||||||
|
<MultiMessage> ::= <len> 0 <MessageSet>
|
||||||
|
<len> ::= <int32>
|
||||||
|
"""
|
||||||
|
req = length_prefix_message(self.create_multi_fetch_request(fetchRequests))
|
||||||
|
log.debug("Sending %d bytes to Kafka", len(req))
|
||||||
|
self._sock.send(req)
|
||||||
|
data = self._consume_response()
|
||||||
|
cur = 0
|
||||||
|
responses = []
|
||||||
|
for request in fetchRequests:
|
||||||
|
(size, _) = struct.unpack('>iH', data[cur:(cur+6)])
|
||||||
|
cur += 6
|
||||||
|
(messages, read) = self.read_message_set(data[cur:(cur+size-2)])
|
||||||
|
cur += size-2
|
||||||
|
responses.append((messages, FetchRequest(request.topic, request.partition, request.offset+read, request.size)))
|
||||||
|
return responses
|
||||||
|
|
||||||
|
def get_offsets(self, offsetRequest):
|
||||||
|
"""
|
||||||
|
Get the offsets for a topic
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
offsetRequest: OffsetRequest
|
||||||
|
|
||||||
|
Returns
|
||||||
|
=======
|
||||||
|
offsets: tuple of offsets
|
||||||
|
|
||||||
|
Wire Format
|
||||||
|
===========
|
||||||
|
<OffsetResponse> ::= <num> [ <offsets> ]
|
||||||
|
<num> ::= <int32>
|
||||||
|
<offsets> ::= <offset> [ <offsets> ]
|
||||||
|
<offset> ::= <int64>
|
||||||
|
|
||||||
|
"""
|
||||||
|
req = length_prefix_message(create_offset_request(offsetRequest))
|
||||||
|
log.debug("Sending %d bytes to Kafka", len(req))
|
||||||
|
self._sock.send(req)
|
||||||
|
|
||||||
|
data = self._consume_response()
|
||||||
|
(num,) = struct.unpack('>i', data[0:4])
|
||||||
|
offsets = struct.unpack('>%dq' % num, data[4:])
|
||||||
|
return offsets
|
||||||
|
|
||||||
|
#######################
|
||||||
|
# Simple User API #
|
||||||
|
#######################
|
||||||
|
|
||||||
|
def send_messages_simple(self, topic, partition, *payloads):
|
||||||
|
"""
|
||||||
|
Send one or more strings to Kafka
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
topic: string
|
||||||
|
partition: int
|
||||||
|
payloads: strings
|
||||||
|
"""
|
||||||
|
messages = tuple([create_message_from_string(payload) for payload in payloads])
|
||||||
|
self.send_message_set(ProduceRequest(topic, partition, messages))
|
||||||
|
|
||||||
|
def iter_messages(self, topic, partition, offset, size, auto=True):
|
||||||
|
"""
|
||||||
|
Helper method that iterates through all messages starting at the offset
|
||||||
|
in the given FetchRequest
|
||||||
|
|
||||||
|
Params
|
||||||
|
======
|
||||||
|
topic: string
|
||||||
|
partition: int
|
||||||
|
offset: int, offset to start consuming from
|
||||||
|
size: number of bytes to initially fetch
|
||||||
|
auto: boolean, indicates whether or not to automatically make the next
|
||||||
|
FetchRequest for more messages
|
||||||
|
|
||||||
|
Returns
|
||||||
|
=======
|
||||||
|
A generator of Messages
|
||||||
|
"""
|
||||||
|
fetchRequest = FetchRequest(topic, partition, offset, size)
|
||||||
|
while True:
|
||||||
|
lastOffset = fetchRequest.offset
|
||||||
|
(messages, fetchRequest) = self.get_message_set(fetchRequest)
|
||||||
|
if fetchRequest.offset == lastOffset:
|
||||||
|
break
|
||||||
|
for message in messages:
|
||||||
|
yield message
|
||||||
|
if auto == False:
|
||||||
|
break
|
||||||
|
|
||||||
|
def close(self):
|
||||||
|
self._sock.close()
|
Reference in New Issue
Block a user