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Event Task

"type" : "EVENT"

The EVENT task is a task used to publish an event into one of the supported eventing systems in Conductor.

Use Cases

Consider a use case where at some point in the execution, an event is published to an external eventing system such as SQS. Event tasks are useful for creating event based dependencies for workflows and tasks.

Supported Queuing Systems

Conductor supports the the following eventing models:

  1. Conductor internal events (prefix: conductor)
  2. SQS (prefix: sqs)
  3. NATS (prefix: nats)
  4. AMQP (prefix: amqp_queue or amqp_exchange)

Configuration

The following parameters are specified at the top level of the task configuration.

Attribute Description
sink External event queue in the format of prefix:location. Prefix is either sqs or conductor and location specifies the actual queue name. e.g. sqs:send_email_queue
asyncComplete Boolean. See below

asyncComplete

  • false to mark status COMPLETED upon execution
  • true to keep it IN_PROGRESS, wait for an external event (via Conductor or SQS or EventHandler) to complete it.

Conductor sink

When producing an event with Conductor as sink, the event name follows the structure: conductor:<workflow_name>:<task_reference_name>

When using Conductor as sink, you have two options: defining the sink as conductor in which case the queue name will default to the taskReferenceName of the Event Task, or specifying the queue name in the sink, as conductor:<queue_name>. The queue name is in the event value of the event Handler, as conductor:<workflow_name>:<queue_name>.

SQS sink

For SQS, use the name of the queue and NOT the URI. Conductor looks up the URI based on the name.

Warning

When using SQS add the ContribsModule to the deployment. The module needs to be configured with AWSCredentialsProvider for Conductor to be able to use AWS APIs.

Output

Tasks's output are sent as a payload to the external event. In case of SQS the task's output is sent to the SQS message a a payload.

name type description
workflowInstanceId String Workflow id
workflowType String Workflow Name
workflowVersion Integer Workflow Version
correlationId String Workflow CorrelationId
sink String Copy of the input data "sink"
asyncComplete Boolean Copy of the input data "asyncComplete
event_produced String Name of the event produced

The published event's payload is identical to the output of the task (except "event_produced").

Examples

Consider an example where we want to publish an event into SQS to notify an external system. 

{
    "type": "EVENT",
    "sink": "sqs:sqs_queue_name",
    "asyncComplete": false
}

An example where we want to publish a messase to conductor's internal queuing system. 

{
    "type": "EVENT",
    "sink": "conductor:internal_event_name",
    "asyncComplete": false
}