MongoFlink is a connector between MongoDB and Apache Flink. It acts as a Flink sink (and an experimental Flink source), and provides transaction mode(which ensures exactly-once semantics) for MongoDB 4.2 above, and non-transaction mode for MongoDB 3.0 above.

MongoFlink is in its early phase, and any use, feedback or contribution is welcome!

• Flink 1.12 above. MongoFlink is built on top of the new sink API added in FLIP-143 or Flink 1.12.0.
• MongoDB 3.0 above. The official MongoDB Java driver supports 3.0 above.
• JDK 1.8 above.

For Maven users, add the following dependency in your project's pom.xml.

<dependency>
    <groupId>org.mongoflink</groupId>
    <artifactId>mongo-flink</artifactId>
    <version>0.1</version>
</dependency>

MongoFlink heavily relies on Flink connector interfaces, but Flink interfaces may not have good cross version compatibility, thus it's recommended to choose the version of MongoFlink that matches the version of Flink in your project.

In case there's no version that fits your need, it's recommended to build your own one. See [Build from source] section below.

Use MongoSink in your Flink application.

    StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

    // non-transactional sink with a flush strategy of 1000 documents or 10 seconds
    Properties properties = new Properties();
    properties.setProperty(MongoOptions.SINK_TRANSACTION_ENABLED, "false");
    properties.setProperty(MongoOptions.SINK_FLUSH_ON_CHECKPOINT, "false");
    properties.setProperty(MongoOptions.SINK_FLUSH_SIZE, String.valueOf(1_000L));
    properties.setProperty(MongoOptions.SINK_FLUSH_INTERVAL, String.valueOf(10_000L));

    env.addSource(...)
       .sinkTo(new MongoSink<>("mongodb://user:[email protected]:27017", "mydb", "mycollection",
                               new StringDocumentSerializer(), properties));

    env.execute();

MongoFlink can be configured using properties.

Checkout the project, and use Maven to build the project locally.

$ mvn verify

Welcome to file an issue if you need help on adopting MongoFlink. Please describe your environment in the issue (e.g. what MongoDB/Flink version you're using).

Welcome to open pull requests if you want to improve MongoFlink. Please state the purpose (and the design if it's a big feature) for better review experience.