AWS Lambda

AWS CLIを使用したLambda関数の作成

# デプロイパッケージの作成
zip function.zip index.js

# Lambda関数の作成
aws lambda create-function \
    --function-name my-function \
    --runtime nodejs14.x \
    --role arn:aws:iam::123456789012:role/lambda-role \
    --handler index.handler \
    --zip-file fileb://function.zip

環境変数を設定したLambda関数の作成

aws lambda create-function \
    --function-name my-function \
    --runtime nodejs14.x \
    --role arn:aws:iam::123456789012:role/lambda-role \
    --handler index.handler \
    --zip-file fileb://function.zip \
    --environment "Variables={DB_HOST=mydb.example.com,DB_USER=admin}"

AWS CLIを使用したLambda関数の呼び出し

aws lambda invoke \
    --function-name my-function \
    --payload '{"key1": "value1", "key2": "value2"}' \
    response.json

非同期呼び出し

aws lambda invoke \
    --function-name my-function \
    --invocation-type Event \
    --payload '{"key1": "value1", "key2": "value2"}' \
    response.json

関数コードの更新

# 新しいデプロイパッケージの作成
zip function-updated.zip index.js

# 関数コードの更新
aws lambda update-function-code \
    --function-name my-function \
    --zip-file fileb://function-updated.zip

関数設定の更新

aws lambda update-function-configuration \
    --function-name my-function \
    --timeout 30 \
    --memory-size 256

Node.jsのシンプルなLambda関数

// index.js
exports.handler = async (event) => {
    console.log('Event: ', JSON.stringify(event, null, 2));
    
    const response = {
        statusCode: 200,
        body: JSON.stringify('Hello from Lambda!'),
    };
    
    return response;
};

S3イベントを処理するPython Lambda関数

# lambda_function.py
import json
import boto3
from datetime import datetime

s3_client = boto3.client('s3')

def lambda_handler(event, context):
    # イベントからバケット名とオブジェクトキーを取得
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    
    # オブジェクトのメタデータを取得
    try:
        response = s3_client.head_object(Bucket=bucket, Key=key)
        object_size = response['ContentLength']
        last_modified = response['LastModified'].strftime('%Y-%m-%d %H:%M:%S')
        
        print(f"Object {key} was uploaded to {bucket}")
        print(f"Size: {object_size} bytes")
        print(f"Last Modified: {last_modified}")
        
        return {
            'statusCode': 200,
            'body': json.dumps({
                'bucket': bucket,
                'key': key,
                'size': object_size,
                'last_modified': last_modified
            })
        }
    except Exception as e:
        print(f"Error: {str(e)}")
        return {
            'statusCode': 500,
            'body': json.dumps({
                'error': str(e)
            })
        }

レイヤーの作成と使用

# レイヤーの作成
aws lambda publish-layer-version \
    --layer-name my-layer \
    --description "My dependencies layer" \
    --license-info "MIT" \
    --zip-file fileb://layer.zip \
    --compatible-runtimes nodejs14.x

# レイヤーを関数に追加
aws lambda update-function-configuration \
    --function-name my-function \
    --layers arn:aws:lambda:us-east-1:123456789012:layer:my-layer:1

プロビジョンドコンカレンシーの設定

aws lambda put-provisioned-concurrency-config \
    --function-name my-function \
    --qualifier prod \
    --provisioned-concurrent-executions 10

関数URLの作成

aws lambda create-function-url-config \
    --function-name my-function \
    --auth-type NONE

Lambda@Edge関数の例

exports.handler = async (event) => {
    const request = event.Records[0].cf.request;
    
    // リクエストヘッダーにカスタムヘッダーを追加
    request.headers['x-custom-header'] = [{ 
        key: 'X-Custom-Header', 
        value: 'Custom Value' 
    }];
    
    return request;
};

Lambda実行ロールの作成

# 信頼ポリシーの作成
cat > trust-policy.json << EOF
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "lambda.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}
EOF

# ロールの作成
aws iam create-role \
    --role-name lambda-s3-role \
    --assume-role-policy-document file://trust-policy.json

# ポリシーのアタッチ
aws iam attach-role-policy \
    --role-name lambda-s3-role \
    --policy-arn arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess

# 基本的なLambda実行ポリシーのアタッチ
aws iam attach-role-policy \
    --role-name lambda-s3-role \
    --policy-arn arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole

CloudWatchアラームの作成

aws cloudwatch put-metric-alarm \
    --alarm-name lambda-errors \
    --comparison-operator GreaterThanThreshold \
    --evaluation-periods 1 \
    --metric-name Errors \
    --namespace AWS/Lambda \
    --period 60 \
    --statistic Sum \
    --threshold 0 \
    --alarm-actions arn:aws:sns:us-east-1:123456789012:my-topic \
    --dimensions "Name=FunctionName,Value=my-function"

X-Rayトレースの有効化

aws lambda update-function-configuration \
    --function-name my-function \
    --tracing-config Mode=Active

Node.jsでのX-Ray SDKの使用

const AWSXRay = require('aws-xray-sdk-core');
const AWS = AWSXRay.captureAWS(require('aws-sdk'));

exports.handler = async (event) => {
    // X-Rayセグメントの作成
    const segment = AWSXRay.getSegment();
    const subsegment = segment.addNewSubsegment('my-subsegment');
    
    try {
        // 処理を実行
        const s3 = new AWS.S3();
        const result = await s3.listBuckets().promise();
        
        subsegment.addAnnotation('BucketCount', result.Buckets.length);
        subsegment.close();
        
        return {
            statusCode: 200,
            body: JSON.stringify(result)
        };
    } catch (error) {
        subsegment.addError(error);
        subsegment.close();
        throw error;
    }
};

CloudWatch Logsのクエリ

aws logs start-query \
    --log-group-name /aws/lambda/my-function \
    --start-time 1636329600 \
    --end-time 1636416000 \
    --query-string "fields @timestamp, @message | filter @message like /ERROR/"

API GatewayとLambdaの統合

# Lambda関数の作成
aws lambda create-function \
    --function-name api-backend \
    --runtime nodejs14.x \
    --role arn:aws:iam::123456789012:role/lambda-api-role \
    --handler index.handler \
    --zip-file fileb://function.zip

# REST APIの作成
aws apigateway create-rest-api \
    --name my-api

# リソースとメソッドの作成
aws apigateway create-resource \
    --rest-api-id abcdef123 \
    --parent-id root-resource-id \
    --path-part items

aws apigateway put-method \
    --rest-api-id abcdef123 \
    --resource-id resource-id \
    --http-method GET \
    --authorization-type NONE

# Lambda関数との統合
aws apigateway put-integration \
    --rest-api-id abcdef123 \
    --resource-id resource-id \
    --http-method GET \
    --type AWS_PROXY \
    --integration-http-method POST \
    --uri arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789012:function:api-backend/invocations