Event Queue

Published Artifacts

Group: com.netflix.conductor

Published Artifact	Description
conductor-kafka-event-queue	Support for integration with Kafka and consume events from it.

Modules

Kafka

https://kafka.apache.org/

kafka-event-queue

Provides ability to consume messages from Kafka.

Usage

To use it in an event handler prefix the event with kafka followed by the topic.

Example:

json

{
    "name": "kafka_test_event_handler",
    "event": "kafka:conductor-event",
    "actions": [
      {
        "action": "start_workflow",
        "start_workflow": {
          "name": "workflow_triggered_by_kafka",
          "input": {
            "payload": "${payload}"
          }
        },
        "expandInlineJSON": true
      }
    ],
    "active": true
}

The data from the kafka event has the format:

json

{
    "key": "key-1",
    "headers": {
        "header-1": "value1"
    },
    "payload": {
        "first": "Marcelo",
        "middle": "Billie",
        "last": "Mertz"
    }
}

key is the key field in Kafka message.
headers is the headers in the kafka message.
payload is the message of the Kafka message.

To access them in the event handler use for example "${payload}" to access the payload property, which contains the kafka message data.

Configuration

To enable the queue use set the following to true.

properties

conductor.event-queues.kafka.enabled=true

There are is a set of shared properties these are:

properties

# If kafka should be used with event queues like SQS or AMPQ
conductor.default-event-queue.type=kafka

# the bootstrap server ot use. 
conductor.event-queues.kafka.bootstrap-servers=kafka:29092

# The dead letter queue to use for events that had some error.
conductor.event-queues.kafka.dlq-topic=conductor-dlq

# topic prefix combined with conductor.default-event-queue.type
conductor.event-queues.kafka.listener-queue-prefix=conductor_

# The polling duration. Start at 500ms and reduce based on how your environment behaves.
conductor.event-queues.kafka.poll-time-duration=500ms

There are 3 clients that should be configured, there is the Consumer, responsible to consuming messages, Publisher that publishes messages to Kafka and the Admin which handles admin operations.

The supported properties for the 3 clients are the ones included in org.apache.kafka:kafka-clients:3.5.1 for each client type.

Consumer properties

Example of consumer settings.

properties

conductor.event-queues.kafka.consumer.client.id=consumer-client
conductor.event-queues.kafka.consumer.auto.offset.reset=earliest
conductor.event-queues.kafka.consumer.enable.auto.commit=false
conductor.event-queues.kafka.consumer.fetch.min.bytes=1
conductor.event-queues.kafka.consumer.max.poll.records=500
conductor.event-queues.kafka.consumer.group-id=conductor-group

Producer properties

Example of producer settings.

properties

conductor.event-queues.kafka.producer.client.id=producer-client
conductor.event-queues.kafka.producer.acks=all
conductor.event-queues.kafka.producer.retries=5
conductor.event-queues.kafka.producer.batch.size=16384
conductor.event-queues.kafka.producer.linger.ms=10
conductor.event-queues.kafka.producer.compression.type=gzip

Admin properties

Example of admin settings.

properties

conductor.event-queues.kafka.admin.client.id=admin-client
conductor.event-queues.kafka.admin.connections.max.idle.ms=10000