AWS for Backend Developers (EC2, S3, RDS, Lambda) · レッスン

Serverless Application Model（SAM）

AWS Serverless Application Model（SAM）フレームワークを使って、サーバーレスアプリケーションを定義、開発、デプロイします。

「Serverless Application Model（SAM）」はCoddyKit上の無料AWS for Backend Developers (EC2, S3, RDS, Lambda)レッスンです。これはレッスン3/4です。下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。これはAWS for Backend Developers (EC2, S3, RDS, Lambda)学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 AWS for Backend Developers (EC2, S3, RDS, Lambda)コースには全4レッスンが含まれています。

このレッスンの一部はまだ翻訳されておらず、英語で表示されています。

What is AWS SAM?

Welcome to the AWS Serverless Application Model (SAM)! SAM is an open-source framework that helps you build, test, and deploy serverless applications on AWS faster and easier.

Think of it as a simplified way to define your serverless resources like Lambda functions and API Gateway endpoints.

SAM: CloudFormation's Helper

At its core, SAM is an extension of AWS CloudFormation. It provides a shorthand syntax for common serverless components.

When you deploy a SAM application, SAM transforms your simplified template into a full AWS CloudFormation template, ensuring you get all the benefits of CloudFormation's robust deployment capabilities.

SAM Template Structure

SAM applications are defined in a SAM template, typically a YAML file named template.yaml. Key sections include:

AWSTemplateFormatVersion: Standard CloudFormation version.
Transform: AWS::Serverless-2016-10-31: This line tells CloudFormation to process the template using SAM.
Resources: Where you define your serverless components (functions, APIs, databases).

Defining a Serverless Function

The primary resource for a Lambda function in SAM is AWS::Serverless::Function. This resource simplifies defining a Lambda function and its related configurations.

You specify properties like Handler (the function entry point), Runtime (e.g., python3.9), and CodeUri (the path to your function's code).

Integrating with API Gateway

To expose your Lambda function via an HTTP endpoint, you can directly define Events within your AWS::Serverless::Function resource.

Using the Api event type automatically provisions an Amazon API Gateway endpoint. You specify the Path and Method for your API route.

Your First SAM Template

Here's a basic template.yaml that defines a Python Lambda function triggered by an API Gateway GET request on the /hello path.

The CodeUri: hello_world/ indicates that the Lambda code is in a local directory named hello_world.

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

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 Lambda Function Code

This is the Python code (app.py) that resides inside the hello_world/ directory. This function will be executed when the API Gateway endpoint is invoked.

It simply returns a JSON response with a "Hello from SAM Lambda!" message.

import json

def lambda_handler(event, context):
    """
    Handles API Gateway requests and returns a simple greeting.
    """
    print("Received an event:", event) # For logging
    return {
        "statusCode": 200,
        "headers": {
            "Content-Type": "application/json"
        },
        "body": json.dumps({
            "message": "Hello from SAM Lambda!"
        }),
    }

# Example local invocation (for direct script testing)
if __name__ == "__main__":
    test_event = {
        "httpMethod": "GET",
        "path": "/hello",
        "requestContext": {"requestId": "test-id-123"},
        "headers": {"User-Agent": "test-client"}
    }
    response = lambda_handler(test_event, None)
    print("Local Response:", response)

Building Your SAM Application

Before you can deploy or even test your application locally, you need to build it. The sam build command processes your template, gathers dependencies, and prepares your code for deployment.

It creates a .aws-sam/build directory containing the processed artifacts.

sam build

Testing Locally with SAM CLI

The SAM CLI provides powerful tools for local testing, saving you time and money by avoiding repeated deployments to AWS.

sam local invoke: Invokes a single Lambda function locally with a given event.
sam local start-api: Starts a local HTTP server that emulates API Gateway, allowing you to interact with your serverless API from your browser or curl.

sam local start-api

Deploying Your Serverless App

Once your application is built and tested locally, you can deploy it to AWS using the sam deploy command.

The first time you deploy, it's recommended to use the --guided flag. This provides an interactive prompt to configure settings like stack name, AWS Region, and S3 bucket for deployment artifacts.

sam deploy --guided

SAM CLI Quick Check

Which SAM CLI command is used to test your serverless API Gateway locally, allowing you to interact with it from your browser or curl?

Recap & Next Steps

Congratulations! You've learned the fundamentals of the AWS Serverless Application Model (SAM).

SAM simplifies serverless development by extending CloudFormation.
You can define Lambda functions and API Gateway endpoints easily in a template.yaml.
The SAM CLI allows you to build, test locally, and deploy your serverless applications efficiently.

SAM is a powerful tool for developing modern, event-driven applications on AWS!

よくある質問

「Serverless Application Model（SAM）」レッスンは無料ですか？

はい。「Serverless Application Model（SAM）」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、AWS for Backend Developers (EC2, S3, RDS, Lambda)コースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 AWS for Backend Developers (EC2, S3, RDS, Lambda)コースには全4レッスンが含まれています。

「Serverless Application Model（SAM）」で何を学びますか？

AWS Serverless Application Model（SAM）フレームワークを使って、サーバーレスアプリケーションを定義、開発、デプロイします。ブラウザで直接実行するハンズオンコードでAWS for Backend Developers (EC2, S3, RDS, Lambda)を演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。

AWS for Backend Developers (EC2, S3, RDS, Lambda)を始めるのに経験は必要ですか？

事前経験は必要ありません。CoddyKitのAWS for Backend Developers (EC2, S3, RDS, Lambda)は初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。これはレッスン3/4です。

「Serverless Application Model（SAM）」レッスンにはどのくらい時間がかかりますか？

ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。

このAWS for Backend Developers (EC2, S3, RDS, Lambda)レッスンでコードを書いて実行できますか？

はい。すべてのAWS for Backend Developers (EC2, S3, RDS, Lambda)レッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。

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