Topic

Topic nodes receive messages and publish them to all Function nodes connected to the output port simultaneously. In AWS, the Topic node is implemented as an Simple Notification Service (SNS) Topic.

The topic will retry outputting a message to a node up to three times if the node fails to process the message.

Message Formats

Events are sent to Function nodes connected to the output of Topic nodes. Messages are batched together into events to ensure high throughput processing. Here is an overview of commonly used event properties:

Property Type Description
Records Array Array of event records.
Records[*].Sns.Timestamp string Transaction timestamp, in ISO 8601 format. Example: 2008-09-22T14:01:54.957Z
Records[*].Sns.Message string Message text. Example: Hello World!


See https://docs.aws.amazon.com/lambda/latest/dg/eventsources.html#eventsources-sns for further details on the event format.

Settings

Name

A label used for the node in the canvas.

Stackery Port Data

When connecting a wire between the output of a Function node to the input of a Topic node, the STACKERY_PORTS environment variable for the Function node will contain the following information in JSON form:

Property Type Description
type string The type of the connected resource. Always set to topic.
id string The Stackery Topic node’s ID. Example: abcd1234.
name string The Stackery Topic node’s name. Example: Records.
topicName string The name of the AWS SNS topic. Example: stackery-98237489374-abcd1234
topicArn string The AWS ARN of the AWS SNS topic. Example: arn:aws:sns:us-west-2:123456789012:stackery-98237489374-abcd1234


See Function Output Port Connections for more details on the STACKERY_PORTS environment variable.

Referenceable Properties

The following properties may be referenced by Function, Docker Service, and Docker Task nodes:

Property Value Example
id Cloud Service Identifier arn:aws:sns:us-east-1:0123456789012:stackery-298374238-8fd73k29s

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