Building Serverless Applications on AWS with TypeScript

The main benefit of using AWS Lambda is that it allows you to run code without provisioning or managing servers. Lambda automatically scales your application by running code in response to each trigger, charges you only for the compute time you consume, and manages the underlying infrastructure on your behalf.

To give an AWS Lambda function access to a DynamoDB table, you can use IAM roles and policies that grant the Lambda function permissions to perform actions on the DynamoDB table, such as read or write operations. You can specify these permissions in the AWS Management Console or via the AWS CLI.

API Gateway serves as an entry point for your serverless applications. It allows you to create, publish, maintain, monitor, and secure APIs at any scale. Additionally, it acts as a front door to handle all the API calls, manage traffic, authorize and monitor access, and handle different versions of the API.

Local testing of AWS Lambda functions can be achieved using tools like AWS SAM CLI or the Serverless Framework, which allow you to invoke Lambda functions locally, emulate AWS API Gateway calls, and provide an environment similar to that of AWS. This helps in debugging and speeding up development cycles by allowing developers to test changes locally before deploying to AWS.

AWS Lambda supports managing different deployment stages using aliases and versions. You can publish different versions of your Lambda functions and point an alias to a specific function version. This setup allows you to easily manage development, testing, and production environments by routing traffic between different versions based on the alias configuration.

To rollback deployments in AWS Lambda, you can use versioning and aliases. By updating the alias to point to a previous stable version of your Lambda function, you can quickly revert to a prior state. This approach provides a straightforward method to manage and undo changes without complex redeployment processes.