File processing in Serverless architecture needs to consider storage services, processing methods, and performance optimization:
Storage service selection:
1. Object storage
- AWS S3: Suitable for storing static files, images, videos, etc.
- Azure Blob Storage: Object storage service on Azure platform
- Advantages: High availability, low cost, unlimited scaling
2. Temporary storage
- /tmp directory: Temporary file system of function instances
- Capacity limits: Usually limited to 512MB-10GB
- Lifecycle: Deleted when function instance is recycled
3. File systems
- EFS: AWS Elastic File System, supports multi-instance sharing
- Applicable scenarios: Need persistent files, multi-instance file sharing
File processing scenarios:
1. File upload
- Presigned URLs: Generate presigned URLs for direct upload to S3
- Multipart upload: Use multipart upload for large files
- Upload callback: Trigger Lambda processing after upload completion
2. File processing
- Image processing: Use Lambda to process image scaling, cropping, format conversion
- Video processing: Use MediaConvert for video transcoding
- Document processing: Use Lambda to process PDF, Word and other documents
3. File download
- Direct download: Download directly through S3 presigned URLs
- Streaming: Use streaming for large files
- CDN acceleration: Use CloudFront to accelerate file access
Performance optimization:
1. Caching strategies
- CDN caching: Use CloudFront to cache static files
- Browser caching: Set appropriate cache headers
- Edge computing: Use Lambda@Edge to process requests at the edge
2. Concurrent processing
- Asynchronous processing: Put file processing tasks into message queues
- Batch processing: Process multiple files in batches
- Parallel processing: Use multiple function instances to process in parallel
Best practices:
- File validation: Validate file type and size before upload
- Security protection: Configure S3 access policies to prevent unauthorized access
- Cost optimization: Choose appropriate storage classes to reduce storage costs
- Monitoring and alerting: Monitor file processing performance and error rates
Candidates should be able to share file processing experience and best practices from actual projects.