CloudFrontKeyValueStoreをつかったリダイレクト設定ラムダ

CloudFrontFunctions.js

import cf from 'cloudfront';

const kvsId = '<CloudFrontKeyValueStoreのID>';

// This fails if the key value store is not associated with the function
const kvsHandle = cf.kvs(kvsId);

// async functionになるので注意！
async function handler(event) {
    // CloudFrontから渡ってくるヘッダからホスト名取得
    const key = event.request.headers.host.value;
  
    let value = "google.com"; // デフォルトリダイレクト先
  
    try {
        value = await kvsHandle.get(key);
    } catch (err) {
        console.log(`Kvs key lookup failed for ${key}: ${err}`);
    }
    var response = {
        statusCode: 301,
        statusDescription: 'Moved Permanently',
        headers: {
            'location': { value: `https://${value}/` } // リダイレクト先URL
        }
    };
    return response;
}

DynamoDBSchema.json

{
  "PK": {
    "S": "REDIRECTS"
  },
  "redirectSettings": {
    "L": [
      {
        "M": {
          "CloudFrontID": {
            "S": "リダイレクト元CloudFrontID"
          },
          "DomainZoneId": {
            "S": "リダイレクト元R53ZoneID"
          },
          "FromDomainName": {
            "S": "from.test.dosmania.link"
          },
          "ToDomainName": {
            "S": "to.test.dosmania.link"
          }
        }
      }
    ]
  }
}

lambdaFunction.mjs

import { DynamoDBClient, GetItemCommand } from "@aws-sdk/client-dynamodb";
import { CloudFrontClient, UpdateDistributionCommand, GetDistributionConfigCommand } from "@aws-sdk/client-cloudfront";
import { Route53Client, ChangeResourceRecordSetsCommand } from "@aws-sdk/client-route-53";
import { CloudFrontKeyValueStoreClient, PutKeyCommand, DescribeKeyValueStoreCommand } from "@aws-sdk/client-cloudfront-keyvaluestore";
import "@aws-sdk/signature-v4-crt";

const ddbClient = new DynamoDBClient();
const cloudFrontClient = new CloudFrontClient();
const route53Client = new Route53Client();
const keyValueStoreClient = new CloudFrontKeyValueStoreClient();

export const handler = async (event) => {
    const tableName = 'redirectTable';
    const partitionKey = 'REDIRECTS';
    const cloudFrontKeyValueStoreARN = '<CloudFrontKeyValueStoreのARN>';
    const cloudFrontFunctionARN = '<CloudFrontFunctionsのARN>';

    // DynamoDBからredirectSettingsを取得
    const params = {
        TableName: tableName,
        Key: {
            'PK': { S: partitionKey }
        }
    };

    try {
        const data = await ddbClient.send(new GetItemCommand(params));
        const redirectSettings = data.Item.redirectSettings.L;

        for (const setting of redirectSettings) {
            // 設定配列データ読み込み
            const cloudFrontID = setting.M.CloudFrontID.S;
            const fromDomainName = setting.M.FromDomainName.S;
            const fromDomainZoneId = setting.M.DomainZoneId.S;
            const toDomainName = setting.M.ToDomainName.S;
            
            console.log("start!");
            // CloudFrontKeyValueStoreにキーと値をセット
            // セットする前に最新のバージョンを取得する必要がある。
            const ret = await keyValueStoreClient.send(new DescribeKeyValueStoreCommand({
                  KvsARN: cloudFrontKeyValueStoreARN
            }));
            // console.log(JSON.stringify(ret,null,2));
            await keyValueStoreClient.send(new PutKeyCommand({
                IfMatch:ret.ETag,  // 現在のバージョン番号
                KvsARN: cloudFrontKeyValueStoreARN,
                Key: fromDomainName,
                Value: toDomainName
            }));
            console.log("値セット完了！");

            // CloudFront FunctionsをViewer Requestにアタッチ
            // 現在のCloudFront設定読み込み
            const distributionConfig = await cloudFrontClient.send(new GetDistributionConfigCommand({
                Id: cloudFrontID
            }));
            // console.log(JSON.stringify(distributionConfig,null,2));
            // 現在のデフォルトキャッシュビヘイビアのviewer-requestにリダイレクト用CloudFrontFunctionsをアッタッチする
            distributionConfig.DistributionConfig.DefaultCacheBehavior.FunctionAssociations = {
                Quantity: 1,
                Items: [
                    {
                        FunctionARN: cloudFrontFunctionARN,
                        EventType: "viewer-request"
                    }
                ]
            };
            // CloudFront設定反映
            const cloudFrontInfo = await cloudFrontClient.send(new UpdateDistributionCommand({
                Id: cloudFrontID,
                IfMatch: distributionConfig.ETag,
                DistributionConfig: distributionConfig.DistributionConfig
            }));
            // const CloudFrontDistributionId = cloudFrontInfo.Distribution.Id;
            // 設定を反映するとCloudFrontドメイン名が変わるので最新をセット
            const CloudFrontDomainName= cloudFrontInfo.Distribution.DomainName ;
            
            // Route 53のAレコードを設定
            await route53Client.send(new ChangeResourceRecordSetsCommand({
                HostedZoneId: fromDomainZoneId,
                ChangeBatch: {
                    Changes: [{
                        Action: 'UPSERT',
                        ResourceRecordSet: {
                            Name: fromDomainName,
                            Type: 'A',
                            AliasTarget: {
                                HostedZoneId: 'Z2FDTNDATAQYW2', // CloudFrontのHosted Zone ID
                                DNSName: CloudFrontDomainName,
                                EvaluateTargetHealth: false
                            }
                        }
                    }]
                }
            }));
            console.log(`ドメイン${fromDomainName} から ${toDomainName} へのリダイレクト設定完了！`);
        }
        console.log("正常終了！");
    } catch (error) {
        console.error(error);
        throw new Error('Error processing redirect settings');
    }
};