goplt/docs/content/stories/epic5/5.3-blob-storage.md

Story 5.3: Blob Storage System

Metadata

• Story ID: 5.3
• Title: Blob Storage System
• Epic: 5 - Infrastructure Adapters
• Status: Pending
• Priority: Medium
• Estimated Time: 5-6 hours
• Dependencies: 1.1, 1.5

Goal

Implement a complete blob storage system using S3 with a clean interface for file upload, download, and management.

Description

This story implements S3-based blob storage with support for file uploads, downloads, signed URLs, and file deletion. It includes an API endpoint for file uploads.

Deliverables

1. Blob Storage Interface (pkg/infra/blob/blob.go)

• BlobStore interface with:
  • Upload(ctx context.Context, key string, data []byte) error
  • Download(ctx context.Context, key string) ([]byte, error)
  • Delete(ctx context.Context, key string) error
  • GetSignedURL(ctx context.Context, key string, ttl time.Duration) (string, error)
  • Exists(ctx context.Context, key string) (bool, error)

2. S3 Implementation (internal/infra/blob/s3_store.go)

• AWS S3 client setup
• All interface methods implemented
• Error handling
• Content type detection

3. File Upload API

• POST /api/v1/files/upload - Upload file
• File validation
• Size limits
• Content type validation

4. Configuration

• S3 config in config/default.yaml:
  • Bucket name
  • Region
  • Credentials (or use IAM role)

5. DI Integration

• Provider function for BlobStore
• Register in DI container

Acceptance Criteria

• Blob storage interface is defined
• S3 implementation works correctly
• Files can be uploaded and downloaded
• Signed URLs are generated correctly
• File upload API works
• Configuration is loaded from config
• Blob store is injectable via DI

Files to Create/Modify

• pkg/infra/blob/blob.go - Blob storage interface
• internal/infra/blob/s3_store.go - S3 implementation
• internal/infra/blob/handler.go - File upload handler
• internal/di/providers.go - Add blob store provider
• config/default.yaml - Add S3 config