Create an HTTP sink connector

The HTTP sink connector enables you to move data from an Aiven for Apache Kafka® cluster to a remote server via HTTP. The full list of parameters and setup details is available in the dedicated GitHub repository.

Prerequisites

To setup an HTTP sink connector, 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 target server:

  • SERVER_URL: The remote server URL that will be called via POST method

  • SERVER_AUTHORIZATION_TYPE: The HTTP authorization type, supported types are none, oauth2 and static

  • TOPIC_LIST: The list of topics to sink divided by comma

and, if you are using Avro as the data format:

  • APACHE_KAFKA_HOST: The hostname of the Apache Kafka service

  • SCHEMA_REGISTRY_PORT: The Apache Kafka’s schema registry port

  • SCHEMA_REGISTRY_USER: The Apache Kafka’s schema registry username

  • SCHEMA_REGISTRY_PASSWORD: The Apache Kafka’s schema registry user password

Note

You can browse the additional parameters available for the static and oauth2 authorization types in the dedicated documentation.

Setup an HTTP sink connector with Aiven Console

The following example demonstrates how to setup an HTTP sink connector for Apache Kafka 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 http_sink.json) with the following content:

{
    "name":"CONNECTOR_NAME",
    "connector.class": "io.aiven.kafka.connect.http.HttpSinkConnector",
    "topics": "TOPIC_LIST",
    "http.url": "SERVER_URL",
    "http.authorization.type": "SERVER_AUTHORIZATION_TYPE",
    "key.converter": "org.apache.kafka.connect.storage.StringConverter",
    "value.converter": "org.apache.kafka.connect.storage.StringConverter"
}

The configuration file contains the following entries:

  • name: the connector name

  • http.url and http.authorization.type: remote server URL and authorization parameters collected in the prerequisite phase.

  • key.converter and value.converter: defines the message data format in the Apache Kafka topic. The io.confluent.connect.avro.AvroConverter converter translates messages from the Avro format. To retrieve the message 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 define how the topic messages will be parsed and need to be included in the connector configuration.

When using Avro as source data format, you need to set the following parameters

  • value.converter.schema.registry.url: pointing to the Aiven for Apache Kafka schema registry URL in the form of https://APACHE_KAFKA_HOST:SCHEMA_REGISTRY_PORT with the APACHE_KAFKA_HOST and SCHEMA_REGISTRY_PORT parameters retrieved in the previous step.

  • value.converter.basic.auth.credentials.source: to the value USER_INFO, since you’re going to login to the schema registry using username and password.

  • value.converter.schema.registry.basic.auth.user.info: passing the required schema registry credentials in the form of SCHEMA_REGISTRY_USER:SCHEMA_REGISTRY_PASSWORD with the SCHEMA_REGISTRY_USER and SCHEMA_REGISTRY_PASSWORD parameters retrieved in the previous step.

Create a Kafka Connect connector with the Aiven Console

To create the connector, access the Aiven Console and select the Aiven for Apache Kafka® or Aiven for Apache Kafka Connect® service where the connector needs to be defined, then:

  1. Click on the Connectors tab

  2. Clink on Create New Connector. This button is only enabled for services with Kafka Connect enabled.

  3. Select the HTTP sink

  4. Under the Common tab, locate the Connector configuration text box and click on Edit

  5. Paste the connector configuration (stored in the http_sink.json file) in the form

  6. Click on 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.

  1. After all the settings are correctly configured, click on Create new connector

  2. Verify the connector status under the Connectors tab

  3. Verify the flow of HTTP POST calls in the target server

Note

Connectors can also be created using the dedicated Aiven CLI command.

Example: Create an HTTP sink connector with a server having no authorization

If you have a topic named iot_measurements containing the following data in JSON format:

Key: 1 Value: {"iot_id":1, "metric":"Temperature", "measurement":14}
Key: 2 Value: {"iot_id":2, "metric":"Humidity", "measurement":60}
Key: 1 Value: {"iot_id":1, "metric":"Temperature", "measurement":16}

You can sink the iot_measurements topic to a remote server over HTTP with the following connector configuration, after replacing the placeholders for SERVER_URL, and SERVER_AUTHORIZATION_TYPE:

{
    "name":"iot_measurements_sink",
    "connector.class": "io.aiven.kafka.connect.http.HttpSinkConnector",
    "topics": "iot_measurements",
    "http.url": "SERVER_URL",
    "http.authorization.type": "SERVER_AUTHORIZATION_TYPE",
    "key.converter": "org.apache.kafka.connect.storage.StringConverter",
    "value.converter": "org.apache.kafka.connect.storage.StringConverter"
}

The configuration file contains the following things to note:

  • "topics": "iot_measurements": setting the topic to sink

  • "value.converter": "org.apache.kafka.connect.json.StringConverter": the message value and key are in plain JSON format without a schema, therefore we can just pass them as plain string via HTTP