kafka-large-message-serde

A Kafka Serde that reads and writes records from and to a blob storage, such as Amazon S3, Azure Blob Storage, and Google Cloud Storage, transparently. Formerly known as kafka-s3-backed-serde.

Getting Started

Serde

You can add kafka-large-message-serde via Maven Central.

Gradle

implementation group: 'com.bakdata.kafka', name: 'large-message-serde', version: '2.0.0'

Maven

<dependency>
    <groupId>com.bakdata.kafka</groupId>
    <artifactId>large-message-serde</artifactId>
    <version>2.0.0</version>
</dependency>

For other build tools or versions, refer to the latest version in MvnRepository.

Make sure to also add Confluent Maven Repository to your build file.

Usage

You can use it from your Kafka Streams application like any other Serde

final Serde<String> serde = new LargeMessageSerde<>();
serde.configure(Map.of(AbstractLargeMessageConfig.BASE_PATH_CONFIG, "s3://my-bucket/",
        LargeMessageSerdeConfig.VALUE_SERDE_CLASS_CONFIG, Serdes.StringSerde.class), false);

The following configuration options are available:

large.message.key.serde Key serde class to use. All serde configurations are also delegated to this serde.

• Type: class
• Default: org.apache.kafka.common.serialization.Serdes$ByteArraySerde
• Importance: high

large.message.value.serde Value serde class to use. All serde configurations are also delegated to this serde.

• Type: class
• Default: org.apache.kafka.common.serialization.Serdes$ByteArraySerde
• Importance: high

large.message.base.path Base path to store data. Must include bucket and any prefix that should be used, e.g., s3://my-bucket/my/prefix/. Available protocols: s3, abs.

• Type: string
• Default: ""
• Importance: high

large.message.max.byte.size Maximum serialized message size in bytes before messages are stored on blob storage.

• Type: int
• Default: 1000000
• Importance: medium

large.message.use.headers Enable if Kafka message headers should be used to distinguish blob storage backed messages. This is disabled by default for backwards compatibility but leads to increased memory usage. It is recommended to enable this option.

• Type: boolean
• Default: false
• Importance: medium

large.message.accept.no.headers Enable if messages read with no headers should be treated as non-backed messages. This allows enabling of large message behavior for data that has been serialized using the wrapped serializer.

• Type: boolean
• Default: false
• Importance: medium

large.message.id.generator Class to use for generating unique object IDs. Available generators are: com.bakdata.kafka.RandomUUIDGenerator, com.bakdata.kafka.Sha256HashIdGenerator, com.bakdata.kafka.MurmurHashIdGenerator.

• Type: class
• Default: com.bakdata.kafka.RandomUUIDGenerator
• Importance: medium

large.message.s3.access.key AWS access key to use for connecting to S3. Leave empty if AWS credential provider chain or STS Assume Role provider should be used.

• Type: password
• Default: ""
• Importance: low

large.message.s3.secret.key AWS secret key to use for connecting to S3. Leave empty if AWS credential provider chain or STS Assume Role provider should be used.

• Type: password
• Default: ""
• Importance: low

large.message.s3.sts.role.arn AWS STS role ARN to use for connecting to S3. Leave empty if AWS Basic provider or AWS credential provider chain should be used.

• Type: string
• Default: ""
• Importance: low

large.message.s3.role.external.id AWS STS role external ID used when retrieving session credentials under an assumed role. Leave empty if AWS Basic provider or AWS credential provider chain should be used.

• Type: string
• Default: ""
• Importance: low

large.message.s3.role.session.name AWS STS role session name to use when starting a session. Leave empty if AWS Basic provider or AWS credential provider chain should be used.

• Type: string
• Default: ""
• Importance: low

large.message.s3.jwt.path Path to an OIDC token file in JSON format (JWT) used to authenticate before AWS STS role authorisation, e.g. for EKS /var/run/secrets/eks.amazonaws.com/serviceaccount/token.

• Type: string
• Default: ""
• Importance: low

large.message.s3.region S3 region to use. Leave empty if default S3 region should be used.

• Type: string
• Default: ""
• Importance: low

large.message.s3.endpoint Endpoint to use for connection to Amazon S3. Leave empty if default S3 endpoint should be used.

• Type: string
• Default: ""
• Importance: low

large.message.s3.path.style.access Enable path-style access for S3 client.

• Type: boolean
• Default: false
• Importance: low

large.message.abs.connection.string Azure connection string for connection to blob storage. Leave empty if Azure credential provider chain should be used.

• Type: password
• Default: ""
• Importance: low

large.message.gs.key.path Google service account key JSON path. Leave empty If the environment variable GOOGLE_APPLICATION_CREDENTIALS is set or if you want to use the default service account provided by your computer engine. For more information about authenticating as a service account please refer to the main documentation.

• Type: string
• Default: ""
• Importance: low

large.message.compression.type The compression type for data stored in blob storage. The default is none (i.e. no compression). Valid values are none, gzip, snappy, lz4 and zstd. Note: this option is only available when large.message.use.headers is enabled.

• Type: string
• Default: "none"
• Importance: low

Kafka Connect

This serde also comes with support for Kafka Connect. You can add kafka-large-message-connect via Maven Central.

Gradle

implementation group: 'com.bakdata.kafka', name: 'large-message-connect', version: '1.1.6'

Maven

<dependency>
    <groupId>com.bakdata.kafka</groupId>
    <artifactId>large-message-connect</artifactId>
    <version>2.0.0</version>
</dependency>

For other build tools or versions, refer to the latest version in MvnRepository.

Usage

To use it with your Kafka Connect jobs, just configure your converter as com.bakdata.kafka.LargeMessageConverter.

In addition to the configurations available for the serde (except large.message.key.serde and large.message.value.serde), you can configure the following:

large.message.converter Converter to use. All converter configurations are also delegated to this converter.

• Type: class
• Default: org.apache.kafka.connect.converters.ByteArrayConverter
• Importance: high

For general guidance on how to configure Kafka Connect converters, please have a look at the official documentation.

Cleaning up the bucket

We also provide a method for cleaning up all files on the blob storage associated with a topic:

final Map<String, Object> properties = ...;
final AbstractLargeMessageConfig config = new AbstractLargeMessageConfig(properties);
final LargeMessageStoringClient storer = config.getStorer()
storer.deleteAllFiles("topic");

Development

If you want to contribute to this project, you can simply clone the repository and build it via Gradle. All dependencies should be included in the Gradle files, there are no external prerequisites.

> git clone git@github.com:bakdata/kafka-large-message-serde.git
> cd kafka-large-message-serde && ./gradlew build

Please note, that we have code styles for Java. They are basically the Google style guide, with some small modifications.

Contributing

We are happy if you want to contribute to this project. If you find any bugs or have suggestions for improvements, please open an issue. We are also happy to accept your PRs. Just open an issue beforehand and let us know what you want to do and why.

License

This project is licensed under the MIT license. Have a look at the LICENSE for more details.