aiokafka

Kafka integration with asyncio.

Project description

asyncio client for Kafka

AIOKafkaProducer

AIOKafkaProducer is a high-level, asynchronous message producer.

Example of AIOKafkaProducer usage:

from aiokafka import AIOKafkaProducer
import asyncio

loop = asyncio.get_event_loop()

async def send_one():
    producer = AIOKafkaProducer(
        loop=loop, bootstrap_servers='localhost:9092')
    # Get cluster layout and initial topic/partition leadership information
    await producer.start()
    try:
        # Produce message
        await producer.send_and_wait("my_topic", b"Super message")
    finally:
        # Wait for all pending messages to be delivered or expire.
        await producer.stop()

loop.run_until_complete(send_one())

AIOKafkaConsumer

AIOKafkaConsumer is a high-level, asynchronous message consumer. It interacts with the assigned Kafka Group Coordinator node to allow multiple consumers to load balance consumption of topics (requires kafka >= 0.9.0.0).

Example of AIOKafkaConsumer usage:

from aiokafka import AIOKafkaConsumer
import asyncio

loop = asyncio.get_event_loop()

async def consume():
    consumer = AIOKafkaConsumer(
        'my_topic', 'my_other_topic',
        loop=loop, bootstrap_servers='localhost:9092',
        group_id="my-group")
    # Get cluster layout and join group `my-group`
    await consumer.start()
    try:
        # Consume messages
        async for msg in consumer:
            print("consumed: ", msg.topic, msg.partition, msg.offset,
                  msg.key, msg.value, msg.timestamp)
    finally:
        # Will leave consumer group; perform autocommit if enabled.
        await consumer.stop()

loop.run_until_complete(consume())

Running tests

Docker is required to run tests. See https://docs.docker.com/engine/installation for installation notes. Also note, that lz4 compression libraries for python will require python-dev package, or python source header files for compilation on Linux.

Setting up tests requirements (assuming you’re within virtualenv on ubuntu 14.04+):

sudo apt-get install -y libsnappy-dev
make setup

Running tests:

make cov

To run tests with a specific version of Kafka (default one is 0.10.1.0) use KAFKA_VERSION variable:

make cov KAFKA_VERSION=0.10.0.0

Test running cheatsheat:

make test FLAGS="-l -x --ff" - run until 1 failure, rerun failed tests fitst. Great for cleaning up a lot of errors, say after a big refactor.

make test FLAGS="-k consumer" - run only the consumer tests.

make test FLAGS="-m 'not ssl'" - run tests excluding ssl.

make test FLAGS="--no-pull" - do not try to pull new docker image before test run.

CHANGES

0.4.0 (2018-01-30)

Major changes:

Full refactor of the internals of AIOKafkaConsumer. Needed to avoid several race conditions in code (PR #286, fixes #258, #264 and #261)
Rewrote Records parsing protocol to allow implementation of newer protocol versions later
Added C extension for Records parsing protocol, boosting the speed of produce/consume routines significantly
Added an experimental batch producer API for unique cases, where user want’s to control batching himself (by @shargan)

Minor changes:

Add timestamp field to produced message’s metadata. This is needed to find LOG_APPEND_TIME configured timestamps.
Consumer.seek() and similar API’s now raise proper ValueError’s on validation failure instead of AssertionError.

Bug fixes:

Fix connections_max_idle_ms option, as earlier it was only applied to bootstrap socket. (PR #299)
Fix consumer.stop() side effect of logging an exception ConsumerStoppedError (issue #263)
Problem with Producer not able to recover from broker failure (issue #267)
Traceback containing duplicate entries due to exception sharing (PR #247 by @Artimi)
Concurrent record consumption rasing InvalidStateError(‘Exception is not set.’) (PR #249 by @aerkert)
Don’t fail GroupCoordinator._on_join_prepare() if commit_offset() throws exception (PR #230 by @shargan)
Send session_timeout_ms to GroupCoordinator constructor (PR #229 by @shargan)

Big thanks to:

@shargan for Producer speed enhancements and the batch produce API proposal/implementation.
@vineet-rh and other contributors for constant feedback on Consumer problems, leading to the refactor mentioned above.

0.3.1 (2017-09-19)

Added AIOKafkaProducer.flush() method. (PR #209 by @vineet-rh)
Fixed a bug with uvloop involving float(“inf”) for timeout. (PR #210 by

dmitry-moroz)
Changed test runner to allow running tests on OSX. (PR #213 by @shargan)

0.3.0 (2017-08-17)

Moved all public structures and errors to aiokafka namespace. You will no longer need to import from kafka namespace.
Changed ConsumerRebalanceListener to support either function or coroutine for on_partitions_assigned and on_partitions_revoked callbacks. (PR #190 by @ask)
Added support for offsets_for_times, beginning_offsets, end_offsets API’s. (issue #164)
Coordinator requests are now sent using a separate socket. Fixes slow commit issue. (issuer #137, issue #128)
Added seek_to_end, seek_to_beginning API’s. (issue #154)
Updated documentation to provide more useful usage guide on both Consumer and Producer interface.

0.2.3 (2017-07-23)

Fixed retry problem in Producer, when buffer is not reset to 0 offset. Thanks to @ngavrysh for the fix in Tubular/aiokafka fork. (issue #184)
Fixed how Producer handles retries on Leader node failure. It just did not work before… Thanks to @blugowski for the help in locating the problem. (issue #176, issue #173)
Fixed degrade in v0.2.2 on Consumer with no group_id. (issue #166)

0.2.2 (2017-04-17)

Reconnect after KafkaTimeoutException. (PR #149 by @Artimi)
Fixed compacted topic handling. It could skip messages if those were compacted (issue #71)
Fixed old issue with new topics not adding to subscription on pattern (issue #46)
Another fix for Consumer race condition on JoinGroup. This forces Leader to wait for new metadata before assigning partitions. (issue #118)
Changed metadata listener in Coordinator to avoid 2 rejoins in a rare condition (issue #108)
getmany will not return 0 results until we hit timeout. (issue #117)

Big thanks to @Artimi for pointing out several of those issues.

0.2.1 (2017-02-19)

Add a check to wait topic autocreation in Consumer, instead of raising UnknownTopicOrPartitionError (PR #92 by fabregas)
Consumer now stops consumption after consumer.stop() call. Any new get* calls will result in ConsumerStoppedError (PR #81)
Added exclude_internal_topics option for Consumer (PR #111)
Better support for pattern subscription when used with group_id (part of PR #111)
Fix for Consumer subscribe and JoinGroup race condition (issue #88). Coordinator will now notice subscription changes during rebalance and will join group again. (PR #106)
Changed logging messages according to KAFKA-3318. Now INFO level should be less messy and more informative. (PR #110)
Add support for connections_max_idle_ms config (PR #113)

0.2.0 (2016-12-18)

Added SSL support. (PR #81 by Drizzt1991)
Fixed UnknownTopicOrPartitionError error on first message for autocreated topic (PR #96 by fabregas)
Fixed next_record recursion (PR #94 by fabregas)
Fixed Heartbeat fail if no consumers (PR #92 by fabregas)
Added docs addressing kafka-python and aiokafka differences (PR #70 by Drizzt1991)
Added max_poll_records option for Consumer (PR #72 by Drizzt1991)
Fix kafka-python typos in docs (PR #69 by jeffwidman)
Topics and partitions are now randomized on each Fetch request (PR #66 by Drizzt1991)

0.1.4 (2016-11-07)

Bumped kafka-python version to 1.3.1 and Kafka to 0.10.1.0.
Fixed auto version detection, to correctly handle 0.10.0.0 version
Updated Fetch and Produce requests to use v2 with v0.10.0 message format on brokers. This allows a timestamp to be associated with messages.
Changed lz4 compression framing, as it was changed due to KIP-57 in new message format.
Minor refactorings

Big thanks to @fabregas for the hard work on this release (PR #60)