Event Source for AWS SNS

This event source subscribes to messages from a AWS SNS topic and sends them as CloudEvents to an event sink.

Prerequisites

SNS Topic (standard)

If you don't already have an AWS SNS standard topic, create one by following the instructions in the Getting started with Amazon SNS guide.

Amazon Resource Name (ARN)

A fully qualified ARN is required to uniquely identify the AWS SNS topic.

SNS topic

As shown in the above screenshot, you can obtain the ARN of a SNS topic from the AWS console. It typically has the following format:

arn:aws:sns:{awsRegion}:{awsAccountId}:{topicName}

Alternatively you can also use the AWS CLI. The following command retrieves the ARN of a SNS topic named MyQueue in the us-west-2 region.

$ aws --region us-west-2 sns list-topics
{
    "Topics": [
        ...
        {
            "TopicArn": "arn:aws:sns:us-west-2:123456789012:MyTopic"
        },
        ...
    ]
}

API Credentials

The TriggerMesh AWS SNS event source authenticates calls to the AWS SNS API using an Access Key. The page at this link contains instructions to create an access key when signed either as the root user or as an IAM user. Take note of the Access Key ID and Secret Access Key, they will be used to create an instance of the event source.

It is considered a good practice to create dedicated users with restricted privileges in order to programmatically access AWS services. Permissions can be added or revoked granularly for a given IAM user by attaching IAM Policies to it.

As an example, the following policy contains the permissions required by the TriggerMesh AWS SNS event source to read and delete messages from any topic linked to the AWS account:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AWSSNSSourceReceiveAdapter",
            "Effect": "Allow",
            "Action": "sns:ConfirmSubscription",
            "Resource": "*"
        },
        {
            "Sid": "AWSSNSSourceReconciler",
            "Effect": "Allow",
            "Action": [
                "sns:ListSubscriptionsByTopic",
                "sns:Subscribe",
                "sns:Unsubscribe"
            ],
            "Resource": "*"
        }
    ]
}

Creating an IAM user

Deploying an Instance of the Source

Open the Bridge creation screen and add a source of type AWS SNS.

Adding an AWS SNS source

In the Source creation form, give a name to the event source and add the following information:

  • Secret: Reference to a TriggerMesh secret containing an Access Key ID and a Secret Access Key to communicate with the AWS SNS API, as described in the previous sections.
  • AWS ARN: ARN of the SNS topic, as described in the previous sections.
  • DeliveryPolicy: Delivery policy to define how Amazon SNS retries the delivery of messages to HTTP/S endpoints.

AWS SNS source form

After clicking the Save button, you will be taken back to the Bridge editor. Proceed to adding the remaining components to the Bridge, then submit it.

Bridge overview

A ready status on the main Bridges page indicates that the event source is ready to receive messages from the AWS SNS topic.

Bridge status

Event Types

The AWS SNS event source emits events of the following type:

  • com.amazon.sns.notification