Kafka Rust Client

Project Status

This project is starting to be maintained by John Ward, the current status is that I am bringing the project up to date with the latest dependencies, removing deprecated Rust code and adjusting the tests.

New Home

Welcome to kafka-rust’s new home: https://github.com/kafka-rust

Documentation

This library is primarily documented through examples in its API documentation.
Documentation about Kafka itself can be found at its project home page.

Installation

This crate works with Cargo and is on crates.io. The API is currently under heavy movement although we do follow semantic versioning (but expect the version number to grow quickly).

[dependencies]
kafka = "0.9"

To build kafka-rust the usual cargo build should suffice. The crate supports various features which can be turned off at compile time. See kafka-rust’s Cargo.toml and cargo’s documentation.

Supported Kafka version

kafka-rust is tested for compatibility with a select few Kafka versions from 0.8.2 to 3.1.0. However, not all features from Kafka 0.9 and newer are supported yet.

Examples

As mentioned, the cargo generated documentation contains some examples. Further, standalone, compilable example programs are provided in the examples directory of the repository.

Consumer

This is a higher-level consumer API for Kafka and is provided by the module kafka::consumer. It provides convenient offset management support on behalf of a specified group. This is the API a client application of this library wants to use for receiving messages from Kafka.

Producer

This is a higher-level producer API for Kafka and is provided by the module kafka::producer. It provides convenient automatic partition assignment capabilities through partitioners. This is the API a client application of this library wants to use for sending messages to Kafka.

KafkaClient

KafkaClient in the kafka::client module is the central point of this API. However, this is a mid-level abstraction for Kafka rather suitable for building higher-level APIs. Applications typically want to use the already mentioned Consumer and Producer. Nevertheless, the main features or KafkaClient are:

Loading metadata
Fetching topic offsets
Sending messages
Fetching messages
Committing a consumer group’s offsets
Fetching a consumer group’s offsets

Bugs / Features / Contributing

There’s still a lot of room for improvement on kafka-rust. Not everything works right at the moment, and testing coverage could be better. Use it in production at your own risk. Have a look at the issue tracker and feel free to contribute by reporting new problems or contributing to existing ones. Any constructive feedback is warmly welcome!

As usually with open source, don’t hesitate to fork the repo and submit a pull request if you see something to be changed. We’ll be happy to see kafka-rust improving over time.

Integration tests

When working locally, the integration tests require that you must have Docker (1.10.0+) and docker-compose (1.6.0+) installed and run the tests via the included run-all-tests script in the tests directory. See the run-all-tests script itself for details on its usage.

Creating a topic

Note unless otherwise explicitly stated in the documentation, this library will ignore requests to topics which it doesn’t know about. In particular it will not try to retrieve messages from non-existing/unknown topics. (This behavior is very likely to change in future version of this library.)

Given a local kafka server installation you can create topics with the following command (where kafka-topics.sh is part of the Kafka distribution):

kafka-topics.sh --topic my-topic --create --zookeeper localhost:2181 --partitions 1 --replication-factor 1

See also Kafka’s quickstart guide for more information.

Alternative/Related projects

rust-rdkafka is an emerging alternative Kafka client library for Rust based on librdkafka. rust-rdkafka provides a safe Rust interface to librdkafka.