Create your application in AWS SAM

After completing Getting started and reading How to use AWS Serverless Application Model (AWS SAM), you will be ready to create an AWS SAM project in your developer environment. Your AWS SAM project will serve as the starting point for writing your serverless application. For a list of AWS SAM CLI sam init command options, see sam init.

The AWS Serverless Application Model Command Line Interface (AWS SAM CLI) sam init command provides options to initialize a new serverless application that consists of:

To create an AWS SAM project, refer to the topics in this sections.

Initialize a new serverless application

Choose a starting template

A template consists of the following:

You can select from a list of available AWS Quick Start Templates or provide your own Custom Template Location.

Choose a runtime

When you choose an AWS Quick Start Template, the AWS SAM CLI prompts you to select a runtime for your Lambda functions. The list of options displayed by the AWS SAM CLI are the runtimes supported natively by Lambda.

You can use any other programming language with a custom runtime. To do this, you need to manually create your starting application structure. You can then use sam init to quickly initialize your application by configuring a custom template location.

From your selection, the AWS SAM CLI creates the starting directory for your Lambda function code and dependencies.

If Lambda supports multiple dependency managers for your runtime, you will be prompted to choose your preferred dependency manager.

Choose a package type

When you choose an AWS Quick Start Template and a runtime, the AWS SAM CLI prompts you to select a package type. The package type determines how your Lambda functions are deployed to use with the Lambda service. The two supported package types are:

To learn more about deployment package types, see Lambda deployment packages in the AWS Lambda Developer Guide.

The following is an example directory structure of an application with a Lambda function packaged as a container image. The AWS SAM CLI downloads the image and creates a Dockerfile in the function's directory to specify the image.

sam-app
├── README.md
├── __init__.py
├── events
│   └── event.json
├── hello_world
│   ├── Dockerfile
│   ├── __init__.py
│   ├── app.py
│   └── requirements.txt
├── samconfig.toml
├── template.yaml
└── tests
    ├── __init__.py
    └── unit
        ├── __init__.py
        └── test_handler.py

The following is an example directory structure of an application with a function packaged as a .zip file archive.

sam-app
├── README.md
├── __init__.py
├── events
│   └── event.json
├── hello_world
│   ├── __init__.py
│   ├── app.py
│   └── requirements.txt
├── samconfig.toml
├── template.yaml
└── tests
    ├── __init__.py
    ├── integration
    │   ├── __init__.py
    │   └── test_api_gateway.py
    ├── requirements.txt
    └── unit
        ├── __init__.py
        └── test_handler.py

Configure AWS X-Ray tracing

You can choose to activate AWS X-Ray tracing. To learn more, see What is AWS X-Ray? in the AWS X-Ray Developer Guide.

If you activate, the AWS SAM CLI configures your AWS SAM template. The following is an example:

Globals:
  Function:
    ...
    Tracing: Active
  Api:
    TracingEnabled: True

Configure monitoring with Amazon CloudWatch Application Insights

You can choose to activate monitoring using Amazon CloudWatch Application Insights. To learn more, see Amazon CloudWatch Application Insights in the Amazon CloudWatch User Guide.

If you activate, the AWS SAM CLI configures your AWS SAM template. The following is an example:

Resources:
  ApplicationResourceGroup:
    Type: AWS::ResourceGroups::Group
    Properties:
      Name:
        Fn::Join:
        - ''
        - - ApplicationInsights-SAM-
          - Ref: AWS::StackName
      ResourceQuery:
        Type: CLOUDFORMATION_STACK_1_0
  ApplicationInsightsMonitoring:
    Type: AWS::ApplicationInsights::Application
    Properties:
      ResourceGroupName:
        Fn::Join:
        - ''
        - - ApplicationInsights-SAM-
          - Ref: AWS::StackName
      AutoConfigurationEnabled: 'true'
    DependsOn: ApplicationResourceGroup

Name your application

Provide a name for your application. The AWS SAM CLI creates a top-level folder for your application using this name.

Options for sam init

The following are some of the main options you can use with the sam init command. For a list of all options, see sam init.

Initialize an application using a custom template location

Use the --location option and provide a supported custom template location. The following is an example:

$ sam init --location https://github.com/aws-samples/sessions-with-aws-sam/raw/master/starter-templates/web-app.zip

Initialize an application without the interactive flow

Use the --no-interactive option and provide your configuration choices at the command line to skip the interactive flow. The following is an example:

$ sam init --no-interactive --runtime go1.x --name go-demo --dependency-manager mod --app-template hello-world

Troubleshooting

To troubleshoot the AWS SAM CLI, see AWS SAM CLI troubleshooting.

Examples

Initialize a new serverless application using the Hello World AWS Starter Template

For this example, see Step 1: Initialize the sample Hello World application in Tutorial: Deploying a Hello World application.

Initialize a new serverless application with a custom template location

The following are examples of providing a GitHub location to your custom template:

$ sam init --location gh:aws-samples/cookiecutter-aws-sam-python
$ sam init --location git+sh://git@github.com/aws-samples/cookiecutter-aws-sam-python.git
$ sam init --location hg+ssh://hg@bitbucket.org/repo/template-name

The following is an example of a local file path:

$ sam init --location /path/to/template.zip

The following is an example of a path reachable by HTTPS:

$ sam init --location https://github.com/aws-samples/sessions-with-aws-sam/raw/master/starter-templates/web-app.zip

Learn more

To learn more about using the sam init command, see the following:

Next steps

Now that you have created your AWS SAM project, you are ready to start authoring your application. See Define your infrastructure with AWS SAM for detailed instructions on the tasks you need to complete to do this.