Create a Debezium source connector from MongoDB to Apache Kafka®#

The Debezium source connector for MongoDB tracks database changes using a MongoDB replica set or shared cluster, and writes them to an Apache Kafka® topic in a standard format where they can be transformed and read by multiple consumers.

Note

You can check the full set of available parameters and configuration options in the connector’s documentation.

Prerequisites#

To setup a Debezium source connector pointing to MongoDB, you need an Aiven for Apache Kafka service with Kafka Connect enabled or a dedicated Aiven for Apache Kafka Connect cluster.

Furthermore you need to collect the following information about the source MongoDB database upfront:

  • MONGODB_HOST: The database hostname

  • MONGODB_PORT: The database port

  • MONGODB_USER: The database user to connect

  • MONGODB_PASSWORD: The database password for the MONGODB_USER

  • MONGODB_DATABASE_NAME: The database name to include in the replica

  • MONGODB_REPLICA_SET_NAME: The name of MongoDB’s replica set

  • APACHE_KAFKA_HOST: The hostname of the Apache Kafka service, only needed when using Avro as data format

  • SCHEMA_REGISTRY_PORT: The Apache Kafka’s schema registry port, only needed when using Avro as data format

  • SCHEMA_REGISTRY_USER: The Apache Kafka’s schema registry username, only needed when using Avro as data format

  • SCHEMA_REGISTRY_PASSWORD: The Apache Kafka’s schema registry user password, only needed when using Avro as data format

Note

If you’re using Aiven for Apache Kafka®, the Kafka related details are available in the Aiven console service Overview tab or via the dedicated avn service get command with the Aiven CLI.

Setup a MongoDB Debezium source connector with Aiven Console#

The following example demonstrates how to setup a Debezium source connector for Apache Kafka to a MongoDB database using the Aiven Console.

Define a Kafka Connect configuration file#

Define the connector configurations in a file (we’ll refer to it with the name debezium_source_mongodb.json) with the following content. Creating a file is not strictly necessary but allows to have all the information in one place before copy/pasting them in the Aiven Console:

{
    "name":"CONNECTOR_NAME",
    "connector.class": "io.debezium.connector.mongodb.MongoDbConnector",
    "mongodb.hosts": "MONGODB_REPLICA_SET_NAME/MONGODB_HOST:MONGODB_PORT",
    "mongodb.name" : "MONGODB_DATABASE_NAME",
    "mongodb.user": "MONGODB_USER",
    "mongodb.password": "MONGODB_PASSWORD",
    "tasks.max":"NR_TASKS",
    "key.converter": "io.confluent.connect.avro.AvroConverter",
    "key.converter.schema.registry.url": "https://APACHE_KAFKA_HOST:SCHEMA_REGISTRY_PORT",
    "key.converter.basic.auth.credentials.source": "USER_INFO",
    "key.converter.schema.registry.basic.auth.user.info": "SCHEMA_REGISTRY_USER:SCHEMA_REGISTRY_PASSWORD",
    "value.converter": "io.confluent.connect.avro.AvroConverter",
    "value.converter.schema.registry.url": "https://APACHE_KAFKA_HOST:SCHEMA_REGISTRY_PORT",
    "value.converter.basic.auth.credentials.source": "USER_INFO",
    "value.converter.schema.registry.basic.auth.user.info": "SCHEMA_REGISTRY_USER:SCHEMA_REGISTRY_PASSWORD"
}

The configuration file contains the following entries:

  • name: the connector name, replace CONNECTOR_NAME with the name you want to use for the connector

  • MONGODB_HOST, MONGODB_PORT, MONGODB_DATABASE_NAME, MONGODB_USER, MONGODB_PASSWORD and MONGODB_REPLICA_SET_NAME: source database parameters collected in the prerequisite phase.

  • tasks.max: maximum number of tasks to execute in parallel. By default this is 1, the connector can use at most 1 task for each collection defined. Replace NR_TASKS with the amount of parallel task based on the number of input collections.

  • key.converter and value.converter: defines the messages data format in the Apache Kafka topic. The io.confluent.connect.avro.AvroConverter converter pushes messages in Avro format. To store the messages schema we use Aiven’s Karapace schema registry as specified by the schema.registry.url parameter and related credentials.

    Note

    The key.converter and value.converter sections are only needed when pushing data in Avro format. If omitted the messages will be defined in JSON format.

    The USER_INFO is not a placeholder, no substitution is needed for that parameter.

Create a Kafka Connect connector with the Aiven Console#

To create a Kafka Connect connector, follow these steps:

  1. Log in to the Aiven Console and select the Aiven for Apache Kafka® or Aiven for Apache Kafka Connect® service where the connector needs to be defined.

  2. Select Connectors from the left sidebar.

  3. Select Create New Connector, the button is enabled only for services with Kafka Connect enabled.

  4. Select Debezium - MongoDB.

  5. In the Common tab, locate the Connector configuration text box and select on Edit.

  6. Paste the connector configuration (stored in the debezium_source_mongodb.json file) in the form.

  7. Select Apply.

    Note

    The Aiven Console parses the configuration file and fills the relevant UI fields. You can review the UI fields across the various tabs and change them if necessary. The changes will be reflected in JSON format in the Connector configuration text box.

  8. After all the settings are correctly configured, select Create new connector.

    Tip

    If you’re using Aiven for Apache Kafka, topics will not be created automatically. Either create them manually following the database.server.name.schema_name.table_name naming pattern or enable the kafka.auto_create_topics_enable advanced parameter.

  1. Verify the connector status under the Connectors screen.

  2. Verify the presence of the data in the target Apache Kafka topic coming from the MongoDB dataset. The topic name is equal to the concatenation of the database and collection name. If you need to change the target table name, you can do so using the Kafka Connect RegexRouter transformation.

You can also create connectors using the Aiven CLI command.