AsyncIO Kinesis Library
Project description
async-kinesis
pip install async-kinesis
Features
- uses queues for both producer and consumer
- producer flushes with put_records() if has enough to flush or after "buffer_time" reached
- consumer iterates over msg queue independent of shard readers
- Configurable to handle Sharding limits but will throttle/retry if required
- ie multiple independent clients are saturating the Shards
- Checkpointing with heartbeats
- deadlock + reallocation of shards if checkpoint fails to heartbeat within "session_timeout"
- processors (aggregator + serializer)
- json line delimited, msgpack
See docs/design for more details. See docs/yetanother as to why reinvent the wheel.
Environment Variables
As required by boto3
AWS_ACCESS_KEY_ID
AWS_SECRET_ACCESS_KEY
Producer
from kinesis import Producer
async with Producer(stream_name="test") as producer:
# Put item onto queue to be flushed via put_records()
await producer.put({'my': 'data'})
Options:
(comments in quotes are Kinesis Limits as per AWS Docs)
Arg | Default | Description |
---|---|---|
session | None | AioSession (to use non default profile etc) |
region_name | None | AWS Region |
buffer_time | 0.5 | Buffer time in seconds before auto flushing records |
put_rate_limit_per_shard | 1000 | "A single shard can ingest up to 1 MiB of data per second (including partition keys) or 1,000 records per second for writes" |
put_bandwidth_limit_per_shard | 1024 | Kb per sec. max is 1024 per shard (ie 1 MiB). Keep below to minimize ProvisionedThroughputExceeded" errors * |
batch_size | 500 | "Each PutRecords request can support up to 500 records" |
max_queue_size | 10000 | put() method will block when queue is at max |
after_flush_fun | None | async function to call after doing a flush (err put_records()) call |
processor | JsonProcessor() | Record aggregator/serializer. Default is JSON without aggregation. Note this is highly inefficient as each record can be up to 1Mib |
retry_limit | None | How many connection attempts should be made before raising a exception |
expo_backoff | None | Exponential Backoff when connection attempt fails |
expo_backoff_limit | 120 | Max amount of seconds Exponential Backoff can grow |
create_stream | False | Creates a Kinesis Stream based on the stream_name keyword argument. Note if stream already existing it will ignore |
create_stream_shards | 1 | Sets the amount of shard you want for your new stream. Note if stream already existing it will ignore |
- Throughput exceeded. The docs (for Java/KPL see: https://docs.aws.amazon.com/streams/latest/dev/kinesis-producer-adv-retries-rate-limiting.html) state:
You can lower this limit to reduce spamming due to excessive retries. However, the best practice is for each producer is to retry for maximum throughput aggressively and to handle any resulting throttling determined as excessive by expanding the capacity of the stream and implementing an appropriate partition key strategy.
Even though our default here is to limit at this threshold (1024kb) in reality the threshold seems lower (~80%). If you wish to avoid excessive throttling or have multiple producers on a stream you will want to set this quite a bit lower.
Consumer
from kinesis import Consumer
async with Consumer(stream_name="test") as consumer:
while True:
async for item in consumer:
print(item)
# caught up.. take a breather~
Options:
(comments in quotes are Kinesis Limits as per AWS Docs)
Arg | Default | Description |
---|---|---|
session | None | AioSession (to use non default profile etc) |
region_name | None | AWS Region |
max_queue_size | 10000 | the fetch() task shard will block when queue is at max |
max_shard_consumers | None | Max number of shards to use. None = all |
record_limit | 10000 | Number of records to fetch with get_records() |
sleep_time_no_records | 2 | No of seconds to sleep when caught up |
iterator_type | TRIM_HORIZON | Default shard iterator type for new/unknown shards (ie start from start of stream). Alternatives are "LATEST" (ie end of stream), "AT_TIMESTAMP" (ie particular point in time, requires defining timestamp arg) |
shard_fetch_rate | 1 | No of fetches per second (max = 5). 1 is recommended as allows having multiple consumers without hitting the max limit. |
checkpointer | MemoryCheckPointer() | Checkpointer to use |
processor | JsonProcessor() | Record aggregator/serializer. Must Match processor used by Producer() |
retry_limit | None | How many connection attempts should be made before raising a exception |
expo_backoff | None | Exponential Backoff when connection attempt fails |
expo_backoff_limit | 120 | Max amount of seconds Exponential Backoff can grow |
create_stream | False | Creates a Kinesis Stream based on the stream_name keyword argument. Note if stream already existing it will ignore |
create_stream_shards | 1 | Sets the amount of shard you want for your new stream. Note if stream already existing it will ignore |
timestamp | None | Timestamp to start reading stream from. Used with iterator type "AT_TIMESTAMP" |
Checkpointers
- memory (the default but kinda pointless)
MemoryCheckPointer()
- redis
RedisCheckPointer(name, session_timeout=60, heartbeat_frequency=15, is_cluster=False)
Requires ENV:
REDIS_HOST
Requires pip install aredis
Processors (Aggregator + Serializer)
Aggregation enable batching up multiple records to more efficiently use the stream. Refer https://aws.amazon.com/blogs/big-data/implementing-efficient-and-reliable-producers-with-the-amazon-kinesis-producer-library/
Class | Aggregator | Serializer | Description |
---|---|---|---|
StringProcessor | SimpleAggregator | StringSerializer | Single String record |
JsonProcessor | SimpleAggregator | JsonSerializer | Single JSON record |
JsonLineProcessor | NewlineAggregator | JsonSerializer | Multiple JSON record separated by new line char |
JsonListProcessor | ListAggregator | JsonSerializer | Multiple JSON record returned by list |
MsgpackProcessor | NetstringAggregator | MsgpackSerializer | Multiple Msgpack record framed with Netstring Protocol (https://en.wikipedia.org/wiki/Netstring) |
KPLJsonProcessor | KPLAggregator | JsonSerializer | Multiple JSON record in a KPL Aggregated Record (https://github.com/awslabs/amazon-kinesis-producer/blob/master/aggregation-format.md) |
KPLStringProcessor | KPLAggregator | StringSerializer | Multiple String record in a KPL Aggregated Record (https://github.com/awslabs/amazon-kinesis-producer/blob/master/aggregation-format.md) |
Note you can define your own processor easily as it's simply a class inheriting the Aggregator + Serializer.
class MsgpackProcessor(Processor, NetstringAggregator, MsgpackSerializer):
pass
Just define a new Serializer class with serialize() and deserialize() methods.
Note:
- Json will use
pip install ujson
if installed - Msgpack requires
pip install msgpack
to be installed - KPL requires
pip install aws-kinesis-agg
to be installed
Benchmark/Example
See benchmark.py for code
50k items of approx 1k (python) in size, using single shard.
Unit Testing
Uses https://github.com/mhart/kinesalite for local testing.
Run tests via docker
docker-compose up --abort-on-container-exit --exit-code-from test
For local testing use
docker-compose up kinesis redis
then within your virtualenv
nosetests
# or run individual test
nosetests tests.py:KinesisTests.test_create_stream_shard_limit_exceeded
Note there are a few test cases using the actual AWS Kinesis (AWSKinesisTests) These require setting an env in order to run
Create an ".env" file with
TESTING_USE_AWS_KINESIS=1
Note you can ignore these tests if submitting PR unless core batching/processing behaviour is being changed.
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