Serverless AWS Lambda Development · Lesson

AWS Serverless Application Model (SAM)

Learn to define, develop, and deploy serverless applications using AWS SAM, an open-source framework for building on AWS.

AWS Serverless Application Model (SAM) is a free Serverless AWS Lambda Development lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Serverless AWS Lambda Development learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Simplify Serverless with AWS SAM

AWS Serverless Application Model (SAM) is an open-source framework that simplifies building and deploying serverless applications on AWS.

It extends AWS CloudFormation, giving you a special, easier syntax for defining serverless resources like Lambda functions, API Gateways, and DynamoDB tables. SAM helps you manage your entire serverless app as a single unit.

SAM Template: The Blueprint

At the core of every SAM application is the template.yaml file. This YAML (or JSON) file acts as the blueprint, describing all the serverless resources that make up your application.

SAM templates are essentially AWS CloudFormation templates, but they include a crucial Transform property that unlocks SAM's simplified, serverless-specific syntax.

Anatomy of a SAM Template

Let's look at the key sections you'll find in a template.yaml file:

AWSTemplateFormatVersion: Standard CloudFormation version.
Transform: AWS::Serverless-2016-10-31: This is vital! It tells CloudFormation to use SAM's simplified syntax.
Description: A short explanation of your application.
Resources: This is where you define all your serverless components like Lambda functions, APIs, and databases.

Defining a Serverless Function

In SAM, you define a Lambda function using the AWS::Serverless::Function resource type. You specify essential properties like its runtime, entry point (handler), memory, and how it gets triggered.

Type: AWS::Serverless::Function: Identifies it as a Lambda.
Handler: The function within your code that AWS Lambda calls to begin execution (e.g., app.lambda_handler).
Runtime: The programming language environment (e.g., python3.9, nodejs16.x).
CodeUri: The local path to your function's source code.
Events: Specifies how your function is invoked (e.g., an API Gateway endpoint).

Our 'Hello World' Lambda Handler

Here's a simple Python Lambda function. It will be the code executed when our serverless function is invoked. It just returns a 'Hello from Lambda!' message.

import json

def lambda_handler(event, context):
    # Log the event for debugging purposes
    print("Received event: " + json.dumps(event))

    # Basic response for API Gateway
    response = {
        "statusCode": 200,
        "body": json.dumps("Hello from Lambda!")
    }
    return response

SAM Template for Our Function

Now, let's define our 'Hello World' Lambda function in a template.yaml. We'll set it up to be triggered by an API Gateway GET request at the /hello path.

This template assumes your Python code (app.py) is in a folder named hello_world/ next to this template.yaml file.

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: A simple "Hello World" serverless application.

Resources:
  HelloWorldFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: app.lambda_handler
      Runtime: python3.9
      CodeUri: hello_world/
      MemorySize: 128
      Timeout: 30
      Events:
        HelloWorldApi:
          Type: Api
          Properties:
            Path: /hello
            Method: GET

The SAM CLI: Your Deployment Tool

The AWS SAM Command Line Interface (CLI) is your main tool for developing and deploying SAM applications. It provides commands to initialize projects, build dependencies, test locally, and deploy your application to AWS.

sam init: Start a new serverless project.
sam build: Package your application code and dependencies.
sam deploy: Deploy your application to AWS CloudFormation.

Building Your SAM Application

Before you can deploy your application, you need to 'build' it. The sam build command collects your code, bundles any dependencies (like Python packages), and prepares everything into a deployable package.

This command creates a .aws-sam directory containing the processed artifacts.

sam build

Deploying Your SAM Application

Once built, use sam deploy to push your application to AWS. This command creates or updates a CloudFormation stack based on your SAM template, provisioning all the necessary resources.

You'll need to specify a unique stack name and an S3 bucket for code artifacts. The --capabilities CAPABILITY_IAM argument acknowledges that your template creates IAM roles.

sam deploy --stack-name my-hello-app \
           --s3-bucket your-unique-s3-bucket-name \
           --capabilities CAPABILITY_IAM \
           --region us-east-1

Quick Check: SAM Template Components

Which of the following are essential components or sections found within a typical AWS SAM template (template.yaml)?

Recap: Your SAM Journey Begins!

You've just learned the fundamentals of AWS SAM!

SAM simplifies serverless application development and deployment using a CloudFormation-based template.
Key components include the template.yaml with its Transform property and Resources section.
The SAM CLI provides commands like sam init, sam build, and sam deploy to manage your applications.

With SAM, you can efficiently define, build, and deploy complex serverless architectures, making it a powerful tool for serverless development.

Frequently asked questions

Is the “AWS Serverless Application Model (SAM)” lesson free?

Yes — the full text of “AWS Serverless Application Model (SAM)” is free to read here on the web, and the Serverless AWS Lambda Development course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Serverless AWS Lambda Development course, upgrade to CoddyKit PRO.

What will I learn in “AWS Serverless Application Model (SAM)”?

Learn to define, develop, and deploy serverless applications using AWS SAM, an open-source framework for building on AWS. You practise Serverless AWS Lambda Development with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Serverless AWS Lambda Development?

No prior experience is required. Serverless AWS Lambda Development on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “AWS Serverless Application Model (SAM)” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Serverless AWS Lambda Development lesson?

Yes. Every Serverless AWS Lambda Development lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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