AWS S3 Lambda Samples

# AWS S3 and Lambda Basic Configuration
# Serverless architecture for file processing and automation

# 1. AWS SAM Template (template.yaml)
AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: S3 Lambda file processing application

Globals:
  Function:
    Runtime: nodejs18.x
    Timeout: 300
    MemorySize: 512
    Environment:
      Variables:
        TABLE_NAME: !Ref FileProcessingTable

Resources:
  # S3 Bucket for file uploads
  FileUploadBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: !Sub 'file-upload-bucket-${AWS::StackName}'
      PublicAccessBlockConfiguration:
        BlockPublicAcls: true
        BlockPublicPolicy: true
        IgnorePublicAcls: true
        RestrictPublicBuckets: true
      BucketEncryption:
        ServerSideEncryptionConfiguration:
          - ServerSideEncryptionByDefault:
              SSEAlgorithm: AES256
      NotificationConfiguration:
        LambdaConfigurations:
          - Event: s3:ObjectCreated:*
            Function: !GetAtt FileProcessorFunction.Arn

  # Lambda function for processing uploaded files
  FileProcessorFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: lambda/
      Handler: index.handler
      Runtime: nodejs18.x
      Environment:
        Variables:
          BUCKET_NAME: !Ref FileUploadBucket
          TABLE_NAME: !Ref FileProcessingTable
      Policies:
        - S3ReadPolicy:
            BucketName: !Ref FileUploadBucket
        - DynamoDBCrudPolicy:
            TableName: !Ref FileProcessingTable

  # DynamoDB table for tracking file processing
  FileProcessingTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: !Sub 'file-processing-table-${AWS::StackName}'
      AttributeDefinitions:
        - AttributeName: fileId
          AttributeType: S
      KeySchema:
        - AttributeName: fileId
          KeyType: HASH
      BillingMode: PAY_PER_REQUEST
      StreamSpecification:
        StreamViewType: NEW_AND_OLD_IMAGES

  # IAM Role for Lambda with S3 and DynamoDB permissions
  LambdaExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub 's3-lambda-execution-role-${AWS::StackName}'
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: sts:AssumeRole
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
      Policies:
        - PolicyName: S3AccessPolicy
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action:
                  - s3:GetObject
                  - s3:PutObject
                  - s3:DeleteObject
                Resource: !Sub 'arn:aws:s3:::${FileUploadBucket}/*'
        - PolicyName: DynamoDBAccessPolicy
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action:
                  - dynamodb:PutItem
                  - dynamodb:GetItem
                  - dynamodb:UpdateItem
                  - dynamodb:Query
                  - dynamodb:Scan
                Resource:
                  - !GetAtt FileProcessingTable.Arn
                  - !Sub '${FileProcessingTable.Arn}/index/*'

Outputs:
  BucketName:
    Description: S3 bucket for file uploads
    Value: !Ref FileUploadBucket
    Export:
      Name: !Sub '${AWS::StackName}-FileUploadBucket'

  FunctionName:
    Description: Lambda function ARN
    Value: !GetAtt FileProcessorFunction.Arn
    Export:
      Name: !Sub '${AWS::StackName}-FileProcessorFunction'

  TableName:
    Description: DynamoDB table name
    Value: !Ref FileProcessingTable
    Export:
      Name: !Sub '${AWS::StackName}-FileProcessingTable'

// Lambda Function for S3 File Processing
// File: lambda/index.js

const AWS = require('aws-sdk');
const sharp = require('sharp');
const { S3Client, GetObjectCommand, PutObjectCommand } = require('@aws-sdk/client-s3');
const { DynamoDBClient, PutItemCommand, UpdateItemCommand } = require('@aws-sdk/client-dynamodb');
const { marshall, unmarshall } = require('@aws-sdk/util-dynamodb');

// Initialize AWS SDK clients
const s3Client = new S3Client({ region: process.env.AWS_REGION });
const dynamoDbClient = new DynamoDBClient({ region: process.env.AWS_REGION });

// Environment variables
const BUCKET_NAME = process.env.BUCKET_NAME;
const TABLE_NAME = process.env.TABLE_NAME;
const THUMBNAIL_FOLDER = 'thumbnails/';

// Supported image formats for processing
const SUPPORTED_FORMATS = ['jpg', 'jpeg', 'png', 'webp', 'gif'];
const THUMBNAIL_SIZES = [150, 300, 600];

/**
 * Main Lambda handler for S3 events
 */
exports.handler = async (event, context) => {
  console.log('Received S3 event:', JSON.stringify(event, null, 2));

  try {
    // Process each record in the S3 event
    for (const record of event.Records) {
      await processS3Record(record);
    }

    return {
      statusCode: 200,
      body: JSON.stringify({
        message: 'Files processed successfully',
        recordsProcessed: event.Records.length
      })
    };
  } catch (error) {
    console.error('Error processing files:', error);

    return {
      statusCode: 500,
      body: JSON.stringify({
        error: 'File processing failed',
        details: error.message
      })
    };
  }
};

/**
 * Process individual S3 record
 */
async function processS3Record(record) {
  const eventName = record.eventName;
  const bucketName = record.s3.bucket.name;
  const objectKey = decodeURIComponent(record.s3.object.key.replace(/\+/g, ' '));

  console.log(`Processing ${eventName} for object: ${objectKey} in bucket: ${bucketName}`);

  // Skip processing for thumbnail files to prevent infinite loops
  if (objectKey.startsWith(THUMBNAIL_FOLDER)) {
    console.log('Skipping thumbnail file');
    return;
  }

  // Extract file extension
  const fileExtension = objectKey.split('.').pop().toLowerCase();

  if (SUPPORTED_FORMATS.includes(fileExtension)) {
    console.log(`Processing supported image format: ${fileExtension}`);
    await processImageFile(bucketName, objectKey, fileExtension);
  } else {
    console.log(`File format ${fileExtension} not supported for image processing`);
    await processGenericFile(bucketName, objectKey);
  }
}

/**
 * Process image files - generate thumbnails and extract metadata
 */
async function processImageFile(bucketName, objectKey, fileExtension) {
  const startTime = Date.now();
  const fileId = generateFileId(objectKey);

  try {
    // Get the original image from S3
    const getObjectCommand = new GetObjectCommand({
      Bucket: bucketName,
      Key: objectKey
    });

    const response = await s3Client.send(getObjectCommand);
    const imageBuffer = await streamToBuffer(response.Body);

    // Extract image metadata using sharp
    const metadata = await sharp(imageBuffer).metadata();

    console.log('Image metadata:', metadata);

    // Generate thumbnails in different sizes
    const thumbnails = await generateThumbnails(imageBuffer, objectKey, fileExtension);

    // Store file information in DynamoDB
    const fileRecord = {
      fileId,
      objectKey,
      bucketName,
      originalSize: imageBuffer.length,
      contentType: response.ContentType,
      width: metadata.width,
      height: metadata.height,
      format: metadata.format,
      size: metadata.size,
      thumbnails,
      processingTime: Date.now() - startTime,
      status: 'completed',
      processedAt: new Date().toISOString(),
      expiresAt: new Date(Date.now() + 30 * 24 * 60 * 60 * 1000).toISOString() // 30 days
    };

    await saveFileRecord(fileRecord);

    console.log(`Successfully processed image: ${objectKey}`);
  } catch (error) {
    console.error(`Error processing image ${objectKey}:`, error);

    // Save error record to DynamoDB
    const errorRecord = {
      fileId,
      objectKey,
      bucketName,
      status: 'failed',
      error: error.message,
      processedAt: new Date().toISOString(),
      expiresAt: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000).toISOString() // 7 days for failed records
    };

    await saveFileRecord(errorRecord);
    throw error;
  }
}

/**
 * Process non-image files
 */
async function processGenericFile(bucketName, objectKey) {
  const fileId = generateFileId(objectKey);
  const startTime = Date.now();

  try {
    // Get object metadata
    const getObjectCommand = new GetObjectCommand({
      Bucket: bucketName,
      Key: objectKey
    });

    const response = await s3Client.send(getObjectCommand);

    // Store file information in DynamoDB
    const fileRecord = {
      fileId,
      objectKey,
      bucketName,
      originalSize: response.ContentLength,
      contentType: response.ContentType,
      processingTime: Date.now() - startTime,
      status: 'completed',
      processedAt: new Date().toISOString(),
      expiresAt: new Date(Date.now() + 30 * 24 * 60 * 60 * 1000).toISOString()
    };

    await saveFileRecord(fileRecord);

    console.log(`Successfully processed file: ${objectKey}`);
  } catch (error) {
    console.error(`Error processing file ${objectKey}:`, error);
    throw error;
  }
}

/**
 * Generate thumbnails in multiple sizes
 */
async function generateThumbnails(imageBuffer, originalKey, fileExtension) {
  const thumbnails = [];
  const baseName = originalKey.split('.').slice(0, -1).join('.');

  for (const size of THUMBNAIL_SIZES) {
    try {
      // Generate thumbnail
      const thumbnailBuffer = await sharp(imageBuffer)
        .resize(size, size, {
          fit: 'inside',
          withoutEnlargement: true
        })
        .jpeg({ quality: 80 })
        .toBuffer();

      // Generate thumbnail key
      const thumbnailKey = `${THUMBNAIL_FOLDER}${baseName}_${size}px.${fileExtension}`;

      // Upload thumbnail to S3
      const putObjectCommand = new PutObjectCommand({
        Bucket: BUCKET_NAME,
        Key: thumbnailKey,
        Body: thumbnailBuffer,
        ContentType: 'image/jpeg',
        Metadata: {
          originalKey,
          size: size.toString()
        }
      });

      await s3Client.send(putObjectCommand);

      thumbnails.push({
        size,
        key: thumbnailKey,
        url: `https://${BUCKET_NAME}.s3.${process.env.AWS_REGION}.amazonaws.com/${thumbnailKey}`,
        sizeBytes: thumbnailBuffer.length
      });

      console.log(`Generated thumbnail: ${thumbnailKey} (${size}px)`);
    } catch (error) {
      console.error(`Error generating ${size}px thumbnail:`, error);
    }
  }

  return thumbnails;
}

/**
 * Save file record to DynamoDB
 */
async function saveFileRecord(fileRecord) {
  const putItemCommand = new PutItemCommand({
    TableName: TABLE_NAME,
    Item: marshall(fileRecord)
  });

  await dynamoDbClient.send(putItemCommand);
}

/**
 * Utility function to generate unique file ID
 */
function generateFileId(objectKey) {
  const timestamp = Date.now();
  const randomString = Math.random().toString(36).substring(2, 8);
  const fileHash = Buffer.from(objectKey).toString('base64').substring(0, 8);
  return `${timestamp}-${fileHash}-${randomString}`;
}

/**
 * Convert stream to buffer
 */
async function streamToBuffer(stream) {
  return new Promise((resolve, reject) => {
    const chunks = [];
    stream.on('data', (chunk) => chunks.push(chunk));
    stream.on('error', reject);
    stream.on('end', () => resolve(Buffer.concat(chunks)));
  });
}

// Package.json for Lambda function
/*
{
  "name": "s3-file-processor",
  "version": "1.0.0",
  "description": "Lambda function for processing S3 file uploads",
  "main": "index.js",
  "dependencies": {
    "@aws-sdk/client-s3": "^3.400.0",
    "@aws-sdk/client-dynamodb": "^3.400.0",
    "@aws-sdk/util-dynamodb": "^3.400.0",
    "sharp": "^0.32.6"
  },
  "devDependencies": {
    "aws-sdk": "^2.1490.0"
  }
}
*/

# Advanced Serverless Architecture Patterns

# 1. Complete Serverless Application with API Gateway, S3, and Lambda
# serverless.yml
service: file-processing-app

frameworkVersion: '3'

provider:
  name: aws
  runtime: nodejs18.x
  region: us-east-1
  stage: ${opt:stage, 'dev'}
  environment:
    STAGE: ${self:provider.stage}
    REGION: ${self:provider.region}
    FILE_TABLE: ${self:service}-files-${self:provider.stage}
    UPLOAD_BUCKET: ${self:service}-uploads-${self:provider.stage}
    THUMBNAIL_BUCKET: ${self:service}-thumbnails-${self:provider.stage}
    PROCESSING_QUEUE_URL: !Ref ProcessingQueue.QueueUrl

  iamRoleStatements:
    - Effect: Allow
      Action:
        - s3:GetObject
        - s3:PutObject
        - s3:DeleteObject
      Resource:
        - !Sub "arn:aws:s3:::${self:provider.environment.UPLOAD_BUCKET}/*"
        - !Sub "arn:aws:s3:::${self:provider.environment.THUMBNAIL_BUCKET}/*"
    - Effect: Allow
      Action:
        - dynamodb:Query
        - dynamodb:Scan
        - dynamodb:GetItem
        - dynamodb:PutItem
        - dynamodb:UpdateItem
        - dynamodb:DeleteItem
      Resource:
        - !GetAtt FilesTable.Arn
        - !Sub "${FilesTable.Arn}/index/*"
    - Effect: Allow
      Action:
        - sqs:SendMessage
        - sqs:ReceiveMessage
        - sqs:DeleteMessage
        - sqs:GetQueueAttributes
      Resource:
        - !GetAtt ProcessingQueue.Arn

functions:
  # API Gateway endpoints
  uploadUrl:
    handler: src/api/uploadUrl.handler
    events:
      - http:
          path: upload/url
          method: post
          cors: true

  fileStatus:
    handler: src/api/fileStatus.handler
    events:
      - http:
          path: files/{fileId}/status
          method: get
          cors: true

  fileList:
    handler: src/api/fileList.handler
    events:
      - http:
          path: files
          method: get
          cors: true

  # S3 trigger for file processing
  processUpload:
    handler: src/processors/processUpload.handler
    events:
      - s3:
          bucket: !Ref UploadBucket
          event: s3:ObjectCreated:*
          rules:
            - prefix: uploads/
          existing: false

  # SQS-based async processing
  thumbnailGenerator:
    handler: src/processors/generateThumbnails.handler
    events:
      - sqs:
          arn:
            !GetAtt ProcessingQueue.Arn
          batchSize: 5
          maximumBatchingWindowInSeconds: 10

  # Scheduled cleanup
  cleanupOldFiles:
    handler: src/jobs/cleanupOldFiles.handler
    events:
      - schedule:
          rate: rate(1 day)
          input:
            cleanupDays: 30

resources:
  Resources:
    UploadBucket:
      Type: AWS::S3::Bucket
      Properties:
        BucketName: ${self:provider.environment.UPLOAD_BUCKET}
        PublicAccessBlockConfiguration:
          BlockPublicAcls: true
          BlockPublicPolicy: true
          IgnorePublicAcls: true
          RestrictPublicBuckets: true
        NotificationConfiguration:
          QueueConfigurations:
            - Event: s3:ObjectCreated:*
              Queue: !GetAtt ProcessingQueue.Arn
              Filter:
                S3Key:
                  Rules:
                    - Name: prefix
                      Value: uploads/

    ThumbnailBucket:
      Type: AWS::S3::Bucket
      Properties:
        BucketName: ${self:provider.environment.THUMBNAIL_BUCKET}
        PublicAccessBlockConfiguration:
          BlockPublicAcls: true
          BlockPublicPolicy: true
          IgnorePublicAcls: true
          RestrictPublicBuckets: true
        CorsConfiguration:
          CorsRules:
            - AllowedOrigins: ['*']
              AllowedHeaders: ['*']
              AllowedMethods: [GET, HEAD]
              MaxAge: 3600

    ProcessingQueue:
      Type: AWS::SQS::Queue
      Properties:
        QueueName: ${self:service}-processing-queue-${self:provider.stage}
        VisibilityTimeout: 900
        MessageRetentionPeriod: 1209600 # 14 days
        RedrivePolicy:
          deadLetterTargetArn: !GetAtt ProcessingDLQ.Arn
          maxReceiveCount: 3

    ProcessingDLQ:
      Type: AWS::SQS::Queue
      Properties:
        QueueName: ${self:service}-processing-dlq-${self:provider.stage}
        MessageRetentionPeriod: 1209600

    FilesTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: ${self:provider.environment.FILE_TABLE}
        BillingMode: PAY_PER_REQUEST
        AttributeDefinitions:
          - AttributeName: fileId
            AttributeType: S
          - AttributeName: userId
            AttributeType: S
          - AttributeName: status
            AttributeType: S
          - AttributeName: createdAt
            AttributeType: N
        KeySchema:
          - AttributeName: fileId
            KeyType: HASH
        GlobalSecondaryIndexes:
          - IndexName: UserStatusIndex
            KeySchema:
              - AttributeName: userId
                KeyType: HASH
              - AttributeName: status
                KeyType: RANGE
            Projection:
              ProjectionType: ALL
          - IndexName: StatusCreatedIndex
            KeySchema:
              - AttributeName: status
                KeyType: HASH
              - AttributeName: createdAt
                KeyType: RANGE
            Projection:
              ProjectionType: ALL
        PointInTimeRecoverySpecification:
          PointInTimeRecoveryEnabled: true
        TTLSpecification:
          AttributeName: expiresAt

    # CloudWatch Alarms
    ProcessingQueueDepthAlarm:
      Type: AWS::CloudWatch::Alarm
      Properties:
        AlarmName: ${self:service}-queue-depth-alarm-${self:provider.stage}
        AlarmDescription: 'Alarm when processing queue depth is too high'
        Namespace: AWS/SQS
        MetricName: ApproximateNumberOfMessagesVisible
        Dimensions:
          - Name: QueueName
            Value: !GetAtt ProcessingQueue.QueueName
        Threshold: 100
        ComparisonOperator: GreaterThanThreshold
        EvaluationPeriods: 2
        Period: 300
        Statistic: Sum
        AlarmActions:
          - !Ref SNSAlertTopic

    # SNS Topic for alerts
    SNSAlertTopic:
      Type: AWS::SNS::Topic
      Properties:
        TopicName: ${self:service}-alerts-${self:provider.stage}

    SNSAlertSubscription:
      Type: AWS::SNS::Subscription
      Properties:
        TopicArn: !Ref SNSAlertTopic
        Protocol: email
        Endpoint: ${ssm:/my-app/alert-email}

# 2. Custom Lambda Authorizer for API Security
# src/auth/customAuthorizer.js
const jwt = require('jsonwebtoken');
const { dynamoDbClient } = require('../lib/aws');

module.exports.handler = async (event) => {
  const token = event.headers.authorization?.replace('Bearer ', '');

  if (!token) {
    return generatePolicy('user', 'Deny', event.methodArn);
  }

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    const user = await getUser(decoded.userId);

    if (!user || !user.isActive) {
      return generatePolicy('user', 'Deny', event.methodArn);
    }

    return generatePolicy(user.userId, 'Allow', event.methodArn, {
      userId: user.userId,
      role: user.role,
      permissions: user.permissions
    });
  } catch (error) {
    console.error('Authorization error:', error);
    return generatePolicy('user', 'Deny', event.methodArn);
  }
};

function generatePolicy(principalId, effect, resource, context = {}) {
  return {
    principalId,
    policyDocument: {
      Version: '2012-10-17',
      Statement: [{
        Action: 'execute-api:Invoke',
        Effect: effect,
        Resource: resource
      }]
    },
    context
  };
}

# 3. EventBridge Event Routing
# serverless.yml snippet (add to functions section)
  eventBridgeHandler:
    handler: src/events/eventBridge.handler
    events:
      - eventBridge:
          eventBus: !Ref CustomEventBus
          pattern:
            source:
              - com.myapp.file.processing
            detailType:
              - FileProcessed
              - ProcessingFailed

# 4. Step Functions Workflow for Complex Processing
# step-functions-workflow.json
{
  "Comment": "Complex file processing workflow",
  "StartAt": "ValidateFile",
  "States": {
    "ValidateFile": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:validateFile",
      "Next": "CheckFileType",
      "Retry": [
        {
          "ErrorEquals": ["States.ALL"],
          "IntervalSeconds": 2,
          "MaxAttempts": 3,
          "BackoffRate": 2.0
        }
      ]
    },
    "CheckFileType": {
      "Type": "Choice",
      "Choices": [
        {
          "Variable": "$.fileType",
          "StringEquals": "image",
          "Next": "GenerateThumbnails"
        },
        {
          "Variable": "$.fileType",
          "StringEquals": "video",
          "Next": "ExtractVideoMetadata"
        },
        {
          "Variable": "$.fileType",
          "StringEquals": "document",
          "Next": "ExtractText"
        }
      ],
      "Default": "ArchiveFile"
    },
    "GenerateThumbnails": {
      "Type": "Parallel",
      "Branches": [
        {
          "StartAt": "SmallThumbnail",
          "States": {
            "SmallThumbnail": {
              "Type": "Task",
              "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:generateThumbnail",
              "Parameters": {
                "fileKey.$": "$.fileKey",
                "size": 150
              },
              "End": true
            }
          }
        },
        {
          "StartAt": "MediumThumbnail",
          "States": {
            "MediumThumbnail": {
              "Type": "Task",
              "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:generateThumbnail",
              "Parameters": {
                "fileKey.$": "$.fileKey",
                "size": 300
              },
              "End": true
            }
          }
        },
        {
          "StartAt": "LargeThumbnail",
          "States": {
            "LargeThumbnail": {
              "Type": "Task",
              "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:generateThumbnail",
              "Parameters": {
                "fileKey.$": "$.fileKey",
                "size": 600
              },
              "End": true
            }
          }
        }
      ],
      "Next": "UpdateDatabase"
    },
    "ExtractVideoMetadata": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:extractVideoMetadata",
      "Next": "UpdateDatabase"
    },
    "ExtractText": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:extractText",
      "Next": "UpdateDatabase"
    },
    "UpdateDatabase": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:updateDatabase",
      "Next": "SendNotification"
    },
    "ArchiveFile": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:archiveFile",
      "Next": "SendNotification"
    },
    "SendNotification": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:sendNotification",
      "End": true
    }
  }
}

# 5. Infrastructure as Code with CDK (TypeScript)
# lib/file-processing-stack.ts
import * as cdk from 'aws-cdk-lib';
import { Construct } from 'constructs';
import {
  aws_s3 as s3,
  aws_lambda as lambda,
  aws_sqs as sqs,
  aws_dynamodb as dynamodb,
  aws_apigateway as apigateway,
  aws_events as events,
  aws_events_targets as targets
} from 'aws-cdk-lib';

export class FileProcessingStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // S3 Buckets
    const uploadBucket = new s3.Bucket(this, 'UploadBucket', {
      bucketName: 'file-uploads',
      encryption: s3.BucketEncryption.S3_MANAGED,
      blockPublicAccess: s3.BlockPublicAccess.BLOCK_ALL,
      removalPolicy: cdk.RemovalPolicy.DESTROY,
    });

    const thumbnailBucket = new s3.Bucket(this, 'ThumbnailBucket', {
      bucketName: 'file-thumbnails',
      encryption: s3.BucketEncryption.S3_MANAGED,
      blockPublicAccess: s3.BlockPublicAccess.BLOCK_ALL,
      removalPolicy: cdk.RemovalPolicy.DESTROY,
    });

    // DynamoDB Table
    const filesTable = new dynamodb.Table(this, 'FilesTable', {
      tableName: 'files',
      partitionKey: { name: 'fileId', type: dynamodb.AttributeType.STRING },
      sortKey: { name: 'createdAt', type: dynamodb.AttributeType.NUMBER },
      billingMode: dynamodb.BillingMode.PAY_PER_REQUEST,
      removalPolicy: cdk.RemovalPolicy.DESTROY,
      timeToLiveAttribute: 'expiresAt',
    });

    // Add GSI
    filesTable.addGlobalSecondaryIndex({
      indexName: 'UserIdIndex',
      partitionKey: { name: 'userId', type: dynamodb.AttributeType.STRING },
      sortKey: { name: 'createdAt', type: dynamodb.AttributeType.NUMBER },
    });

    // SQS Queue
    const processingQueue = new sqs.Queue(this, 'ProcessingQueue', {
      queueName: 'file-processing-queue',
      visibilityTimeout: cdk.Duration.minutes(15),
      retentionPeriod: cdk.Duration.days(14),
      deadLetterQueue: {
        maxReceiveCount: 3,
        queue: new sqs.Queue(this, 'ProcessingDLQ', {
          queueName: 'file-processing-dlq',
        }),
      },
    });

    // Lambda Functions
    const fileProcessor = new lambda.Function(this, 'FileProcessor', {
      runtime: lambda.Runtime.NODEJS_18_X,
      handler: 'index.handler',
      code: lambda.Code.fromAsset('lambda/processor'),
      memorySize: 1024,
      timeout: cdk.Duration.minutes(5),
      environment: {
        UPLOAD_BUCKET: uploadBucket.bucketName,
        THUMBNAIL_BUCKET: thumbnailBucket.bucketName,
        FILES_TABLE: filesTable.tableName,
        PROCESSING_QUEUE_URL: processingQueue.queueUrl,
      },
    });

    // Grant permissions
    uploadBucket.grantRead(fileProcessor);
    thumbnailBucket.grantReadWrite(fileProcessor);
    filesTable.grantReadWriteData(fileProcessor);
    processingQueue.grantSendMessages(fileProcessor);

    // EventBridge for event routing
    const eventBus = new events.EventBus(this, 'FileProcessingEventBus', {
      eventBusName: 'file-processing-events',
    });

    // EventBridge rules
    const fileProcessedRule = new events.Rule(this, 'FileProcessedRule', {
      eventBus,
      eventPattern: {
        source: ['com.myapp.file.processor'],
        detailType: ['FileProcessed'],
      },
    });

    fileProcessedRule.addTarget(new targets.LambdaFunction(fileProcessor));
  }
}