This assumes you have already configured the aws command line tool. If not, check out my article on Getting Started with the AWS CLI.

A Simple Notification Service (SNS) Topic can be used to create notification alerts, such as an email notification. This uses the messaging services pub sub model.

• pub (publish) - create a new alert in a Topic
• sub (subscribe) - get alerts in a Topic

Before setting up sub (subscribers), you will to create an SNS Topic. Check out my article on Creating a Simple Notification Service (SNS) Topics using the AWS CLI.

~]$ aws sns create-topic --name my-topic 
{
    "TopicArn": "arn:aws:sns:us-east-1:123456789012:my-topic"
}

There are various types of subscriptions.

• application - messages published to the topic will be delivered to an EndpointArn for a mobile app or device - the message must be JSO
• email - messages published to the topic will be emailed to the subscriber
• email-json - messages published to the topic will be emailed to the subscriber - the message must be JSON
• firehouse - messages published to the topic will be delivered to an AWS Kinesis Data Firehose delivery stream - the message must be JSON
• http - messages published to the topic will be POST to an HTTP url - the message must be JSON
• https - messages published to the topic will be POST to an HTTPS url - the message must be JSON
• lambda - messages published to the topic will be sent to a Lambda Function
• sms - messages published to the topic will be published to an SMS device (e.g. cellphone)
• Simple Queue Service (SQS) - messages published to the topic will be put onto a SQS queue

For example, the aws sns subscribe command can be used to subscribe an email to the topic.

 ~]$ aws sns subscribe --topic-arn arn:aws:sns:us-east-1:123456789012:my-topic --protocol email --notification-endpoint john.doe@example.com
{
    "SubscriptionArn": "pending confirmation"
}

Or, the aws sns subscribe command can be used to subscribe a Lambda Function to the topic.

~]$ aws sns subscribe --topic-arn arn:aws:sns:us-east-1:123456789012:my-topic --protocol lambda --notification-endpoint arn:aws:lambda:us-east-1:123456789012:function:my-lambda-function
{
    "SubscriptionArn": "arn:aws:sns:us-east-1:123456789012:my-topic:e68a4a47-ce56-48a5-865d-31f5920c4355"
}

This creates a Lambda Trigger. For example, over in the AWS Lambda console, you should have an SNS trigger with your Lambda Function.