The Amazon Kinesis Client Library for Java (Amazon KCL) enables Java developers to easily consume and process data from Amazon Kinesis.
- Provides an easy-to-use programming model for processing data using Amazon Kinesis
- Helps with scale-out and fault-tolerant processing
- Sign up for AWS — Before you begin, you need an AWS account. For more information about creating an AWS account and retrieving your AWS credentials, see AWS Account and Credentials in the AWS SDK for Java Developer Guide.
- Sign up for Amazon Kinesis — Go to the Amazon Kinesis console to sign up for the service and create an Amazon Kinesis stream. For more information, see Create an Amazon Kinesis Stream in the Amazon Kinesis Developer Guide.
- Minimum requirements — To use the Amazon Kinesis Client Library, you'll need Java 1.7+. For more information about Amazon Kinesis Client Library requirements, see Before You Begin in the Amazon Kinesis Developer Guide.
- Using the Amazon Kinesis Client Library — The best way to get familiar with the Amazon Kinesis Client Library is to read Developing Record Consumer Applications in the Amazon Kinesis Developer Guide.
After you've downloaded the code from GitHub, you can build it using Maven. To disable GPG signing in the build, use this command: mvn clean install -Dgpg.skip=true
For producer-side developers using the Kinesis Producer Library (KPL), the KCL integrates without additional effort. When the KCL retrieves an aggregated Amazon Kinesis record consisting of multiple KPL user records, it will automatically invoke the KPL to extract the individual user records before returning them to the user.
To make it easier for developers to write record processors in other languages, we have implemented a Java based daemon, called MultiLangDaemon that does all the heavy lifting. Our approach has the daemon spawn a sub-process, which in turn runs the record processor, which can be written in any language. The MultiLangDaemon process and the record processor sub-process communicate with each other over STDIN and STDOUT using a defined protocol. There will be a one to one correspondence amongst record processors, child processes, and shards. For Python developers specifically, we have abstracted these implementation details away and expose an interface that enables you to focus on writing record processing logic in Python. This approach enables KCL to be language agnostic, while providing identical features and similar parallel processing model across all languages.
- Support timeouts for calls to the MultiLang Daemon
This adds support for setting a timeout when dispatching records to the client record processor. If the record processor doesn't respond within the timeout the parent Java process will be terminated. This is a temporary fix to handle cases where the KCL becomes blocked while waiting for a client record processor.
The timeout for the this can be set by adding
timeoutInSeconds = <timeout value>
. The default for this is no timeout.
Setting this can cause the KCL to exit suddenly, before using this ensure that you have an automated restart for your application
- Execute graceful shutdown on its own thread
- Added support for controlling the size of the lease renewer thread pool
- Require Java 8 and later
Java 8 is now required for versions 1.8.0 of the amazon-kinesis-client and later.
- Added support for graceful shutdown in MultiLang Clients
- Updated documentation for
v2.IRecordProcessor#shutdown
, andKinesisClientLibConfiguration#idleTimeBetweenReadsMillis
- Updated to version 1.11.151 of the AWS Java SDK
- Correctly handle throttling for DescribeStream, and save accumulated progress from individual calls.
- Upgrade to version 1.11.115 of the AWS Java SDK
- Fixed an issue building JavaDoc for Java 8.
- Reduce Throttling Messages to WARN, unless throttling occurs 6 times consecutively.
- Fixed two bugs occurring in requestShutdown.
- Fixed a bug that prevented the worker from shutting down, via requestShutdown, when no leases were held.
- Fixed a bug that could trigger a NullPointerException if leases changed during requestShutdown.
- PR #139
- Upgraded the AWS SDK Version to 1.11.91
- Use an executor returned from
ExecutorService.newFixedThreadPool
instead of constructing it by hand. - Correctly initialize DynamoDB client, when endpoint is explicitly set.
- Upgrade to the newest AWS Java SDK.
- Added a direct dependency on commons-logging.
- Make ShardInfo public to allow for custom ShardPrioritization strategies.
- MultiLangDaemon Feature Updates The MultiLangDaemon has been upgraded to use the v2 interfaces, which allows access to enhanced checkpointing, and more information during record processor initialization. The MultiLangDaemon clients must be updated before they can take advantage of these new features.
- General
- Allow disabling shard synchronization at startup.
- Applications can disable shard synchronization at startup. Disabling shard synchronization can application startup times for very large streams.
- PR #102
- Applications can now request a graceful shutdown, and record processors that implement the IShutdownNotificationAware will be given a chance to checkpoint before being shutdown.
- This adds a new interface, and a new method on Worker.
- PR #109
- Solves Issue #79
- Allow disabling shard synchronization at startup.
- MultiLangDaemon
- Add support for time based iterators (See GetShardIterator Documentation)
- Allow Prioritization of Parent Shards for Task Assignment
- PR #95
The
KinesisClientLibconfiguration
now supports providing aShardPrioritization
strategy. This strategy controls how theWorker
determines whichShardConsumer
to call next. This can improve processing for streams that split often, such as DynamoDB Streams.
- PR #95
The
- Remove direct dependency on
aws-java-sdk-core
, to allow independent versioning.- PR #92 You may need to add a direct dependency on aws-java-sdk-core if other dependencies include an older version.
- Change LeaseManager to call DescribeTable before attempting to create the lease table.
- Allow DynamoDB lease table name to be specified
- Add approximateArrivalTimestamp for JsonFriendlyRecord
- Shutdown lease renewal thread pool on exit.
- Wait for CloudWatch publishing thread to finish before exiting.
- Added unit, and integration tests for the library.
- Upgrade to AWS SDK for Java 1.11.14
- Maven Artifact Signing Change
- Artifacts are now signed by the identity
Amazon Kinesis Tools <amazon-kinesis-tools@amazon.com>
- Artifacts are now signed by the identity
- Fix format exception caused by DEBUG log in LeaseTaker Issue # 68
- Support for specifying max leases per worker and max leases to steal at a time.
- Support for specifying initial DynamoDB table read and write capacity.
- Support for parallel lease renewal.
- Support for graceful worker shutdown.
- Change DefaultCWMetricsPublisher log level to debug. PR # 49
- Avoid NPE in MLD record processor shutdown if record processor was not initialized. Issue # 29
- Expose approximateArrivalTimestamp for Records in processRecords API call.
- Restores compatibility with dynamodb-streams-kinesis-adapter (which was broken in 1.4.0).
- KCL maven artifact 1.5.0 does not work with JDK 7. This release addresses this issue.
- Metrics Enhancements
- Support metrics level and dimension configurations to control CloudWatch metrics emitted by the KCL.
- Add new metrics that track time spent in record processor methods.
- Disable WorkerIdentifier dimension by default.
- Exception Reporting — Do not silently ignore exceptions in ShardConsumer.
- AWS SDK Component Dependencies — Depend only on AWS SDK components that are used.
- Integration with the Kinesis Producer Library (KPL)
- Automatically de-aggregate records put into the Kinesis stream using the KPL.
- Support checkpointing at the individual user record level when multiple user records are aggregated into one Kinesis record using the KPL.
See Consumer De-aggregation with the KCL for details.
- A new metric called "MillisBehindLatest", which tracks how far consumers are from real time, is now uploaded to CloudWatch.
- MultiLangDaemon — Changes to the MultiLangDaemon to make it easier to provide a custom worker.
- Multi-Language Support — Amazon KCL now supports implementing record processors in any language by communicating with the daemon over STDIN and STDOUT. Python developers can directly use the Amazon Kinesis Client Library for Python to write their data processing applications.
- Checkpointing at a specific sequence number — The IRecordProcessorCheckpointer interface now supports checkpointing at a sequence number specified by the record processor.
- Set region — KinesisClientLibConfiguration now supports setting the region name to indicate the location of the Amazon Kinesis service. The Amazon DynamoDB table and Amazon CloudWatch metrics associated with your application will also use this region setting.