start_backend.py

import sys
import subprocess
def check_dependencies():
    """Check if required packages are installed"""
    required_packages = [
        'fastapi',
        'uvicorn',
        'torch',
        'transformers',
        'clip',
        'PIL'
    ]
    missing = []
    for package in required_packages:
        try:
            if package == 'PIL':
                __import__('PIL')
            else:
                __import__(package)
        except ImportError:
            missing.append(package)
    return missing
def main():
    print("=" * 80)
    print("VQA BACKEND API - STARTUP CHECK")
    print("=" * 80)
    print("\n📦 Checking dependencies...")
    missing = check_dependencies()
    if missing:
        print(f"\n❌ Missing packages: {', '.join(missing)}")
        print("\n💡 To install missing packages:")
        print("   pip install -r requirements_api.txt")
        print("\nOr if you already have VQA dependencies installed:")
        print("   pip install fastapi uvicorn python-multipart")
        sys.exit(1)
    print("✅ All dependencies found!")
    print("\n📁 Checking model checkpoints...")
    import os
    base_checkpoint = "vqa_checkpoint.pt"
    spatial_checkpoint = "vqa_spatial_checkpoint.pt"
    if not os.path.exists(base_checkpoint):
        print(f"❌ Missing: {base_checkpoint}")
        print("   Please ensure the base model checkpoint is in the project root")
        sys.exit(1)
    if not os.path.exists(spatial_checkpoint):
        print(f"❌ Missing: {spatial_checkpoint}")
        print("   Please ensure the spatial model checkpoint is in the project root")
        sys.exit(1)
    print(f"✅ Found {base_checkpoint}")
    print(f"✅ Found {spatial_checkpoint}")
    print("\n" + "=" * 80)
    print("🚀 STARTING BACKEND API SERVER")
    print("=" * 80)
    print("\n📋 Configuration:")
    print("  - Host: 0.0.0.0 (accessible from network)")
    print("  - Port: 8000")
    print("\n🔗 Access URLs:")
    print("  - Local: http://localhost:8000")
    print("  - Network: http://<your-ip>:8000")
    print("  - Docs: http://localhost:8000/docs")
    print("\n💡 For mobile testing:")
    print("  1. Find your local IP: ipconfig (Windows) or ifconfig (Mac/Linux)")
    print("  2. Update API_URL in mobile app to http://<your-ip>:8000")
    print("  3. Ensure phone and computer are on same network")
    print("=" * 80 + "\n")
    try:
        from backend_api import app
        import uvicorn
        uvicorn.run(
            app,
            host="0.0.0.0",
            port=8000,
            log_level="info"
        )
    except Exception as e:
        print(f"\n❌ Error starting server: {e}")
        print("\nPlease check:")
        print("  1. All dependencies are installed")
        print("  2. Model checkpoints are present")
        print("  3. No other service is using port 8000")
        sys.exit(1)
if __name__ == "__main__":
    main()