refactoring-serverless

Serverless Days Tokyo 2023

サーバーレスというと、真っ先に思い浮かべるのが AWS Lambda だと思いますが、AWS Lambda 以外にも API Gateway や Step Functions, Event Bridge など様々なサービスと統合されてフルスタックなサーバーレス構成が取れるようになっています。かつては Lamnbda で 全てのビジネスロジックを書いていたところが 周辺の AWS サービスに処理を移譲することができるようになってきました 。このように Lambda のアプリケーションコードを、いかに AWS のサービスにオフロードしていくのか、CDK のコード例も交えながら、リファクタリングの手法・パターンがあるのか、ご説明しています。

Transcript

1. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   淡路 大輔
   アマゾン ウェブ サービス ジャパン合同会社
   ソリューションアーキテクト
   S E R V E R L E S S D A Y S T O K Y O 2 0 2 3
   Refactoring serverless
   ※ 本資料に記載されているプログラムはプレゼンテーション向けに簡略化された表記である場合があります
   

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2. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   Daisuke Awaji
   Amazon Web Services Japan
   Solutions Architect
   3
   @gee0awa
   

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3. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   History of AWS Lambda
   4
   サーバーレスと出会ってから何年経ちましたか？
   

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4. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved. 5
   2014 2015 2016 2017 2018 2019
   2020 2021 2022 2023 2024
   Introducing
   AWS Lambda
   Available in Tokyo
   5 Minute Functions
   Access resources
   within a VPC
   Up to 15 minutes
   Custom runtimes
   Provisioned
   concurrency
   Supports EFS,
   container images
   Lambda extentions
   10GB Memory
   Graviton2
   10GB /tmp
   function URL
   Lambda SnapStart
   Response payload
   streaming
   10th
   Anniversary
   Introducing Amazon API Gateway
   Introducing Amazon EventBridge
   Introducing AWS Step Functions
   2004 Introducing Amazon SQS
   2006 Introducing Amazon S3
   ~ 2006
   Support SQS as Event Source
   Step Functions
   Express Workflows
   Step Functions
   AWS SDK Integration
   

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5. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   How to design
   Serverless Application
   6
   

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6. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved. 7
   AWS Lambda
   

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7. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved. 8
   Function
   Node.js
   Python
   Java
   C#
   Go
   Ruby
   Runtime API
   Container images
   Service
   Many more…
   Event
   データの更新
   API リクエスト
   状態の変更
   etc…
   

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8. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved. 9
   Event Service
   データの更新
   API リクエスト
   状態の変更
   Many more…
   etc…
   Service integration
   

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9. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
   Refactoring to Serverless
   10
   Reduce glue code, extend glue service
   

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10. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    既存のコード本体を再構築し、
    外部の動作を変更せずに
    内部構造を変更するための規律ある⼿法
    Martin Fowler, Refactoring.com
    リファクタリングとは
    

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11. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    既存のコード本体を再構築し、
    外部の動作を変更せずに
    内部構造を変更するための規律ある⼿法
    Martin Fowler, Refactoring.com
    リファクタリングとは
    

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12. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    リファクタリングとテスト駆動開発（TDD）
    RED（失敗するテストを書く）
    GREEN（テストを通す）
    リファクタリング
    TDD
    

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13. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Serverlessland - Testing Patterns Collection
    14
    https://serverlessland.com/testing/patterns
    

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14. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Serverless Refactoring Pattern
    15
    Extract send message
    (using Lambda Destination)
    AWS Step Functions
    Service Integration
    Send Message via
    EventBridge Pipes
    02 03
    01
    

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15. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Serverless Refactoring Pattern
    16
    Extract send message
    (using Lambda Destination)
    AWS Step Functions
    Service Integration
    Send Message via
    EventBridge Pipes
    02 03
    01
    

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16. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Extract send message (using Lambda Destination)
    17
    AWS Lambda
    Amazon SQS
    (success)
    Amazon SNS
    async
    invocation
    Amazon SQS
    (failure)
    https://aws.amazon.com/jp/blogs/compute/introducing-aws-lambda-destinations/
    

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17. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Extract send message (using Lambda Destination)
    18
    AWS Lambda
    import { SQS } from "aws-sdk";
    export const handler = async (event) => {
    const result = // Business Logic
    const params = {
    QueueUrl: process.env.QUEUE_URL,
    MessageBody: result,
    };
    await sqs.sendMessage(params).promise();
    };
    

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18. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Extract send message (using Lambda Destination)
    19
    AWS Lambda
    QueueUrl: process.env.QUEUE_URL,
    await sqs.sendMessage(params).promise();
    ・トポロジーが環境変数に隠れている
    ・アプリケーションコードにロジックとサービスの依存関係が混在
    

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19. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Extract send message (using Lambda Destination)
    20
    AWS Lambda AWS Lambda
    export const handler = async (event) => {
    const result = // Business Logic
    return { message: result };
    };
    AWS CDK
    new Function(this, ”orderFunction", {
    runtime: Runtime.NODEJS_18_X,
    code: Code.fromAsset("app/functions//index.ts”),
    handler: ”order.handler",
    onSuccess: new SqsDestination(queue),
    });
    Original Refactored
    ・トポロジーは CDK コードに集約される
    ・アプリケーションコードには、ロジックのみ記述される
    import { SQS } from "aws-sdk";
    export const handler = async (event) => {
    const result = // Business Logic
    const params = {
    QueueUrl: process.env.QUEUE_URL,
    MessageBody: result,
    };
    await sqs.sendMessage(params).promise();
    };
    ・トポロジーが環境変数に隠れている
    ・アプリケーションコードにロジックとサービスの依存関係が混在
    

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20. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Extract send message – Error handling
    21
    AWS Lambda AWS Lambda
    export const handler = async (event) => {
    const result = // Business Logic
    return { message: result };
    };
    AWS CDK
    new Function(this, ”orderFunction", {
    runtime: Runtime.NODEJS_18_X,
    code: Code.fromAsset("app/functions//index.ts”),
    handler: ”order.handler",
    onSuccess: new SqsDestination(queue),
    onFailure: new SqsDestination(failureQueue),
    });
    Original Refactored
    import { SQS } from "aws-sdk";
    export const handler = async (event) => {
    try {
    const result = // Business Logic
    const params = {
    QueueUrl: process.env.QUEUE_URL,
    MessageBody: result,
    };
    await sqs.sendMessage(params).promise();
    } catch (e) {
    const error = // Error handling Logic
    await sqs.sendMessage(error).promise();
    }
    };
    

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21. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Extract send message – 注意するポイント
    22
    ・Lambda の非同期呼び出しのみサポート
    ・SQS への送信処理は Function の処理の最後に実⾏される
    複数の Queue に送信するシーンでは活⽤できない
    複数の Queue に “同⼀” メッセージを送信したい場合は SNS を Destination の送信先に設定し、Fan Out する
    ・SDK による実装と⽐べて、SQS への送信メッセージの形式が変更される
    SQS Message using AWS SDK SQS Message using Lambda Destination
    

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22. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    サーバーレスをリファクタリングする目的
    23
    アプリ要件に適⽤する
    AWS の機能追加に適応する
    コストを削減する
    ランタイム特性を改善する
    マネージドサービスを活⽤する
    

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23. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Serverless Refactoring Pattern
    24
    Extract send message
    (using Lambda Destination)
    AWS Step Functions
    Service Integration
    Send Message via
    EventBridge Pipes
    02 03
    01
    

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24. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    AWS Step Functions Service Integration
    25
    AWS Step Functions workflow
    Lambda: Invoke
    Detect Labels
    start
    Pass state
    Extract Name
    Choice state
    Is Pizza?
    Fail state
    Failed
    Succeed state
    Passed
    End
    Lambda Function
    Amazon Rekognition
    image
    Amazon S3
    Image Bucket
    Detect Labels API
    AWS Step Functions workflow
    Rekognition:
    Detect Object
    start
    Pass state
    Extract Name
    Choice state
    Is Pizza?
    Fail state
    Failed
    Succeed state
    Passed
    End
    Amazon Rekognition
    image
    Amazon S3
    Image Bucket
    AWS Step Functions から
    直接 AWS サービスの API をコールする
    

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25. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    AWS Step Functions Service Integration
    26
    ・ランタイム要素（Lambda）を無くすことで、コスト・実⾏時間・複雑さを減らす
    Lambda の同時実⾏数消費の緩和、 15 分の timeout の壁を越える
    ライブラリのアップデートなどの運⽤負荷も軽減する
    ・余分なサービスホップを排除することで、レイテンシーを減らす
    

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26. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    AWS Lambda
    27
    const handler = async (event) => {
    const result = await rekognition.detectLabels({
    Image: {
    S3Object: {
    Bucket: event.s3Bucket, Name: event.imageName }
    },
    });
    };
    AWS CDK
    const detectObjectLambda = new lambda.Function(this, {…});
    const detectObject = new tasks.LambdaInvoke(this, "Detect Object", {
    lambdaFunction: detectObjectLambda,
    payload: sfn.TaskInput.fromObject({
    s3Bucket: imageBucket.bucketName,
    imageName: this.IMAGE_TO_LABEL,
    }),
    outputPath: "$.Payload",
    });
    Original
    AWS Step Functions Service Integration
    

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27. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    AWS Lambda
    28
    const result = await rekognition.detectLabels({
    Bucket: event.s3Bucket, Name: event.imageName }
    AWS CDK
    const detectObjectLambda = new lambda.Function(this, {…});
    Glue Code としての Lambda
    Step Functions workflow だけで完結しない複雑さ
    Lambda コードにトポロジーが隠蔽されてしまう
    Original
    AWS Step Functions Service Integration
    

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28. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    AWS Lambda
    29
    const handler = async (event) => {
    const result = await rekognition.detectLabels({
    Image: {
    S3Object: {
    Bucket: event.s3Bucket, Name: event.imageName }
    },
    });
    };
    AWS CDK
    const detectObjectLambda = new lambda.Function(this, {…});
    const detectObject = new tasks.LambdaInvoke(this, "Detect Object", {
    lambdaFunction: detectObjectLambda,
    payload: sfn.TaskInput.fromObject({
    s3Bucket: imageBucket.bucketName,
    imageName: this.IMAGE_TO_LABEL,
    }),
    outputPath: "$.Payload",
    });
    AWS CDK
    const detectObject = new tasks.CallAwsService(this,””, {
    service: "rekognition",
    action: "detectLabels",
    parameters: {
    Image: {
    S3Object: {
    Bucket: imageBucket.bucketName,
    Name: this.IMAGE_TO_LABEL,
    },
    },
    },
    …
    });
    AWS Lambda
    不要
    Original Refactored
    AWS Step Functions Service Integration
    

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29. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Serverless Refactoring Pattern
    30
    Extract send message
    (using Lambda Destination)
    AWS Step Functions
    Service Integration
    Send Message via
    EventBridge Pipes
    02 03
    01
    

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30. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Send Message via EventBridge Pipes
    31
    DynamoDB にドメインイベントを保存してから、 EventBridge にイベントを送信する
    Original
    Lambda
    Application
    EventBridge
    DynamoDB
    Lambda
    Function
    Table
    Event
    Custom
    event bus
    Integration
    ・トポロジーが環境変数に隠れている（DynamoDB テーブル名, Event Bus 名など）
    Rollback
    どうする？
    ・複数サービスへの通信が、同じトランザクションスコープではない
    

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31. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Send Message via EventBridge Pipes
    32
    Stream Pipes
    Original
    Lambda
    Application
    EventBridge
    Integration
    DynamoDB
    Lambda
    Function
    Table Event Custom
    event bus
    Refactored
    EventBridge
    Lambda
    Application
    EventBridge
    DynamoDB
    Lambda
    Function
    Table
    Event
    Custom
    event bus
    Integration
    

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32. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Send Message via EventBridge Pipes
    33
    ・ビジネスロジックの明確化
    Event Bridge への送信ロジックがアプリケーションコードから排除される
    ・トポロジーの明確化
    イベントの送信先は Lambda Function の環境変数で指定せず
    ⾃動化コード（AWS CDK, CloudFormation など）に委譲される
    ・トランザクションの整合性保証
    Lambda のエラーハンドリングやロールバック実装を簡略化
    ・DynamoDB Streams による dedupe
    同じ Item を put しても DDB Strems は最初の変更のみ Capture する
    

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33. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Lambda Function の粒度
    34
    

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34. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    “Lambda-lith”
    35
    AWS Lambda Amazon DynamoDB
    Amazon API Gateway
    Client
    /*
    /create
    /update
    /delete
    ルーティングロジックを
    内包した Function
    ・セキュリティ（IAM Role）
    ・パフォーマンス設定（メモリ、CPU）
    ・クォータ（同時実⾏数など）
    ・スケーリング
    Function 単位に適⽤される設定
    

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35. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    “Nano Lambda”
    36
    Amazon DynamoDB
    Amazon API Gateway
    Client
    /create
    /update
    /delete
    

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36. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved. 37
    https://speakerdeck.com/_kensh/monolith-first-serverless-development
    AWS Dev Day 2023
    

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37. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    delete.js
    “Nano Lambda”
    38
    Amazon DynamoDB
    Amazon API Gateway
    Client
    /create
    /update
    /delete
    import { DynamoDB } from "aws-sdk";
    const dynamodb = new DynamoDB();
    export const handler = async (event: any) => {
    const params = {
    TableName: "serverless-days-tokyo-2023",
    Key: {
    id: { S: event.id },
    },
    };
    try {
    const data = await dynamodb.getItem(params).promise();
    return { body: JSON.stringify(data) };
    } catch (err) {
    return { error: err };
    }
    };
    update.js
    import { DynamoDB } from "aws-sdk";
    const dynamodb = new DynamoDB();
    export const handler = async (event: any) => {
    const params = {
    TableName: "serverless-days-tokyo-2023",
    Key: {
    id: { S: event.id },
    },
    };
    try {
    const data = await dynamodb.getItem(params).promise();
    return { body: JSON.stringify(data) };
    } catch (err) {
    return { error: err };
    }
    };
    create.js
    import { DynamoDB } from "aws-sdk";
    const dynamodb = new DynamoDB();
    export const handler = async (event: any) => {
    const params = {
    TableName: "serverless-days-tokyo-2023",
    Key: {
    id: { S: event.id },
    name: { S: event.name },
    },
    };
    try {
    const data = await dynamodb.putItem(params).promise();
    return { body: JSON.stringify(data) };
    } catch (err) {
    return { error: err };
    }
    };
    

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38. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    API Gateway to Step Functions
    39
    AWS Step Functions Express Workflow を REST API に活⽤する
    start
    What’s method?
    End
    Choice state
    DynamoDB
    GET
    DynamoDB
    PUT
    DynamoDB
    POST
    DynamoDB
    DELETE
    AWS Step Functions Express workflow
    Amazon API Gateway
    Client
    sync
    ・ワークフローとロジックの可視化
    ・Lambda ランタイムの削減
    ・コスト効率の向上
    Express workflow は
    同期的なレスポンスが可能
    

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39. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Serverlesspresso
    40
    AWS Workshop 🚀
    サーバーレスで構築されたイベント駆動型のコーヒー注⽂アプリ
    

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40. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Serverlesspresso Order Manager workflow
    41
    Order Manager API
    Mobile Order
    App
    Barista
    App
    AWS Workshop 🚀
    オーダー管理アプリを Step Functions で実装しよう
    

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41. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    まとめ
    42
    

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42. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    まとめ
    ・単なる “Gule Code” としての Lambda をやめることで
    AWS プラットフォームの恩恵を最⼤化する
    ・AWS CDK のような⾃動化コードでトポロジーを表現することで
    役割を明確化し、変更に柔軟なアーキテクチャにしていく
    ・Lambda Function の粒度を⾒つめ直す
    “Nano Lambda” が唯⼀解ではない、”Lambda-lith” は必ずしも悪ではない
    43
    

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43. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Serverlessland – Refactoring to Serverless
    44
    https://serverlessland.com/content/guides/refactoring-serverless/introduction
    

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44. SERVERLESS DAYS TOKYO 2023 – REFACTORING SERVERLESS
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    Thank you!
    © 2023, Amazon Web Services, Inc. or its affiliates. All rights reserved.
    淡路 ⼤輔
    アマゾン ウェブ サービス ジャパン合同会社
    ソリューションアーキテクト
    @gee0awa
    

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