Publish events with the Event task

EVENT publishes a JSON message through a registered event-queue provider. It is the generic publishing task: use KAFKA_PUBLISH when the message contract needs Kafka-specific keys, headers, serializers, or producer controls.

Task parameters

Parameter	Required	Behavior
`sink`	Yes	`provider:<provider-specific destination>`; expressions resolve at runtime
`inputParameters`	No	User payload fields
`asyncComplete`	No	Defaults to `false`; when true the task remains `IN_PROGRESS` after publish

In OSS, registered provider identifiers are conductor, kafka, sqs, nats, jsm, nats_stream, amqp_queue, and amqp_exchange, subject to the corresponding server module being enabled. The provider owns the destination grammar after the first colon; for example, it might be a Kafka topic, an SQS queue URL, a NATS subject, or an AMQP queue/exchange.

Conductor sink expansion

conductor becomes conductor:<workflowName>:<taskReferenceName>.
conductor:<suffix> becomes conductor:<workflowName>:<suffix>.

The event handler must listen on the expanded name.

Published payload and output

The task begins with its resolved input parameters and adds workflow metadata:

Field	Value
`workflowInstanceId`	Parent workflow execution ID
`workflowType`	Parent workflow name
`workflowVersion`	Parent version
`correlationId`	Parent correlation ID
`taskToDomain`	Parent domain map

The task output also contains event_produced, the expanded sink. The published message is the task output without event_produced. The Event task uses its task ID as the broker message identity, so consumers can use that stable value for duplicate detection.

Completion behavior

With asyncComplete: false, a successful publish completes the task. With asyncComplete: true, publishing succeeds but the task remains IN_PROGRESS; an external task update or an event-handler complete_task/fail_task action must resolve it.

Example

{
  "name": "publish_order_status",
  "taskReferenceName": "publish_order_status",
  "type": "EVENT",
  "sink": "conductor:order-status",
  "inputParameters": {
    "orderId": "${workflow.input.orderId}",
    "status": "READY"
  },
  "asyncComplete": false
}

For a practical first-use walkthrough, see Publish events. Use Event-Driven Orchestration for the provider matrix, routing, webhooks, signals, and delivery observability.