Event Source for Amazon SNS

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

Prerequisite(s)

• SNS Topic (standard)
• Amazon Resource Name (ARN)
• API Credentials

SNS Topic (standard)

If you don't already have an Amazon 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 Amazon 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 MyTopic 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 event source for Amazon SNS authenticates calls to the AWS API using AWS Access Keys. The page Understanding and getting your AWS credentials contains instructions to create access keys when signed-in 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 Amazon 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": "*"
        }
    ]
}

Deploying an Instance of the Source

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

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 Amazon 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.

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.

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

Event Types

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

• com.amazon.sns.notification