What is the AWS Serverless Application Model (AWS SAM)? - AWS Serverless Application Model

What is the AWS Serverless Application Model (AWS SAM)?

AWS Serverless Application Model (AWS SAM) is an open-source framework for building serverless applications using infrastructure as code (IaC). With AWS SAM’s shorthand syntax, developers declare AWS CloudFormation resources and specialized serverless resources that are transformed to infrastructure during deployment. This framework includes two main components: the AWS SAM CLI and the AWS SAM project. The AWS SAM project is the application project directory that is created when you run sam init. The AWS SAM project includes files like the AWS SAM template, which includes the template specification (the shorthand syntax you use to declare resources).

When to use AWS SAM

AWS SAM is an ideal IaC solution for scenarios where you want simplified serverless development with the full power of AWS CloudFormation. For example, you can use SAM for:

  • Serverless applications: You can use SAM to quickly define AWS Lambda functions, Amazon API Gateway APIs, Amazon DynamoDB tables, and other serverless resources with minimal code.

  • AWS CloudFormation enhancement: You can combine SAM with existing CloudFormation templates to add serverless components to traditional infrastructure. SAM resources work alongside standard CloudFormation resources in the same template.

  • Local development and testing: You can use the SAM CLI to test Lambda functions locally, simulate API Gateway endpoints, and debug serverless applications on your development machine before deploying to AWS.

  • CI/CD for serverless: You can build deployment pipelines using SAM templates that automatically generate the CloudFormation infrastructure needed for staging and production environments.

  • Migration from console-created resources: You can convert Lambda functions and API Gateway resources created in the AWS Management Console into infrastructure as code using SAM templates.

Comparing AWS SAM with other IaC tools

  • Use SAM instead of CloudFormation to simplify serverless resource definitions while maintaining template compatibility.

  • Use SAM instead of AWS CDK if you prefer a declarative approach to describing your infrastructure rather than a programmatic one.

  • Combine SAM with AWS CDK by using SAM CLI's local testing features to enhance your CDK applications.

Key features

AWS SAM offers a variety of benefits that improve the developer experience by allowing you to:

Define your application infrastructure code quickly, using less code

Author AWS SAM templates to define your serverless application infrastructure code. Deploy your templates directly to AWS CloudFormation to provision your resources.

Manage your serverless applications through their entire development lifecycle

Use the AWS SAM CLI to manage your serverless application through the authoring, building, deploying, testing, and monitoring phases of your development lifecycle. For more information, see The AWS SAM CLI.

Quickly provision permissions between resources with AWS SAM connectors

Use AWS SAM connectors in your AWS SAM templates to define permissions between your AWS resources. AWS SAM transforms your code into the IAM permissions required to facilitate your intent. For more information, see Managing resource permissions with AWS SAM connectors.

Continuously sync local changes to the cloud as you develop

Use the AWS SAM CLI sam sync command to automatically sync local changes to the cloud, speeding up your development and cloud testing workflows. For more information, see Introduction to using sam sync to sync to AWS Cloud.

Manage your Terraform serverless applications

Use the AWS SAM CLI to perform local debugging and testing of your Lambda functions and layers. For more information, see AWS SAM CLI Terraform support.

Related information