AWS SAM CLI

The Amazon Web Services (AWS) Serverless Application Model (SAM) CLI is an open-source command-line tool that you can use to build, test, and deploy serverless applications. The SAM CLI provides a Lambda-like execution environment that lets you locally build, test and debug applications defined by AWS SAM templates. It is available for a variety of operating systems and Linux distributions, and supports the Arm architecture.

Before you begin

Follow the instructions below to install and try the latest version of the AWS SAM CLI for Ubuntu on Arm.

Confirm you are using an Arm machine by running:

    

        
        
uname -m

    

The output should be:

    

        
        aarch64

        
    

If you see a different result, you are not using an Arm-based computer running 64-bit Linux.

Running the AWS SAM CLI requires Docker. Refer to the Docker Install Guide for installation instructions. Confirm Docker is running before installing the SAM CLI.

Python and Python pip are also required to run the SAM CLI example.

To install, run the following command:

    

        
        
sudo apt install python-is-python3 python3-pip -y

    

Download and install the AWS SAM CLI

There are two options to install the SAM CLI, you can select your preferred method:

• From a zip file.
• Using the Python pip command.

Download and install from zip file

Use wget:

    

        
        
wget https://github.com/aws/aws-sam-cli/releases/latest/download/aws-sam-cli-linux-arm64.zip
unzip aws-sam-cli-linux-arm64.zip -d sam-install
sudo ./sam-install/install

    

Install the SAM CLI using Python pip

    

        
        
sudo apt install python3-venv -y
python -m venv .venv
source .venv/bin/activate
pip install aws-sam-cli

    

Confirm that the SAM CLI has been installed

    

        
        
sam --version

    

The version should be printed on screen:

    

        
        SAM CLI, version 1.125.0

        
    

Example application

You can use the AWS SAM CLI to build and deploy a simple “Hello World” serverless application that includes the line uname -m to check the platform it is running on, by following these steps.

1. Create the project

Use the code below, adjusting the runtime argument if you have a different version of Python:

    

        
        
sam init --runtime python3.12 --architecture arm64 --dependency-manager pip --app-template hello-world --name uname-app --no-interactive

    

2. Change to the new directory:

    

        
        
cd uname-app

    

3. Modify the hello_world/app.py file to include the command uname -m

Use a text editor to replace the contents of the hello_world/app.py file with the code below:

    

        
        
import json
import os

def lambda_handler(event, context):
    """Sample pure Lambda function

    Parameters
    ----------
    event: dict, required
        API Gateway Lambda Proxy Input Format

        Event doc: https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-input-format

    context: object, required
        Lambda Context runtime methods and attributes

        Context doc: https://docs.aws.amazon.com/lambda/latest/dg/python-context-object.html

    Returns
    ------
    API Gateway Lambda Proxy Output Format: dict

        Return doc: https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html
    """

    ret = os.popen('uname -m').read()

    return {
        "statusCode": 200,
        "body": json.dumps({
            "message": ret,
            # "location": ip.text.replace("\n", "")
        }),
    }

    

4. Build the application:

    

        
        
sam build

    

5. Test the deployed application:

    

        
        
sam local invoke "HelloWorldFunction" -e events/event.json

    

The output below shows the results from the command uname -m and the value of aarch64 confirms an Arm Linux computer:

    

        
        Invoking app.lambda_handler (python3.12)                                                                                                                             
Local image was not found.                                                                                                                                           
Removing rapid images for repo public.ecr.aws/sam/emulation-python3.12                                                                                               
Building image........................................................................................................................
Using local image: public.ecr.aws/lambda/python:3.12-rapid-arm64.                                                                                                    
                                                                                                                                                                     
Mounting /home/ubuntu/uname-app/.aws-sam/build/HelloWorldFunction as /var/task:ro,delegated, inside runtime container                                                
START RequestId: 7221da4d-346d-4e2e-831e-dcde1cb47b5b Version: $LATEST
END RequestId: 513dbd6f-7fc0-4212-ae13-a9a4ce2f21f4
REPORT RequestId: 513dbd6f-7fc0-4212-ae13-a9a4ce2f21f4	Init Duration: 0.26 ms	Duration: 84.22 ms	Billed Duration: 85 ms	Memory Size: 128 MB	Max Memory Used: 128 MB	
{"statusCode": 200, "body": "{\"message\": \"aarch64\\n\"}"}

        
    

You are ready to use the AWS SAM CLI to build more complex functions and deploy them into AWS. Make sure to select arm64 as the architecture for your Lambda functions.