Lambda with SQS/SNS Triggers

Lambda functions are at the heart of serverless, but how do they know when to run? They respond to events!

An event is anything that happens in your AWS environment, like a file upload to S3, a new item in DynamoDB, or in this lesson, a message arriving in SQS or SNS.

Using SQS and SNS to trigger Lambda enables powerful event-driven architectures. This means services communicate through events, making systems more flexible and scalable.

Amazon SQS (Simple Queue Service) is a managed message queue service. When you configure an SQS queue as a Lambda trigger, Lambda polls the queue for messages.

Here's how it works:

• Lambda continuously checks the SQS queue.
• When messages are available, Lambda retrieves a batch of them.
• It then invokes your function for each batch or for individual messages, depending on configuration.
• After successful processing, Lambda deletes the messages from the queue.