start_app.py

#!/usr/bin/env python
"""
Entry point for the Lin application.
This script starts both the Flask application and Celery scheduler components.
"""
import os
import sys
import subprocess
import platform
import time
from pathlib import Path

def check_redis():
    """Check if Redis is running."""
    try:
        import redis
        client = redis.Redis(host='localhost', port=6379, db=0)
        client.ping()
        print("✓ Redis connection successful")
        return True
    except Exception as e:
        print(f"✗ Redis connection failed: {e}")
        print("Please start Redis server first:")
        print("  Windows: redis-server")
        print("  Linux/Mac: sudo systemctl start redis")
        return False

def start_celery_components():
    """Start Celery worker and beat scheduler in background processes."""
    print("Starting Celery components...")
    
    project_root = Path(__file__).parent.resolve() # Get the project root directory
    backend_dir = project_root / "backend"
    
    # Prepare the environment with updated PYTHONPATH
    env = os.environ.copy()
    # Prepend the project root to PYTHONPATH so 'backend' package can be found
    current_pythonpath = env.get('PYTHONPATH', '')
    env['PYTHONPATH'] = str(project_root) + os.pathsep + current_pythonpath if current_pythonpath else str(project_root)

    # Start Celery worker
    worker_cmd = [
        sys.executable, "-m", "celery",
        "-A", "celery_config:celery_app",
        "worker",
        "--loglevel=info",
        "--pool=solo",
        "--max-tasks-per-child=100"
    ]
    
    # Start Celery beat
    beat_cmd = [
        sys.executable, "-m", "celery",
        "-A", "celery_config:celery_app",
        "beat",
        "--loglevel=info",
        "--schedule=/tmp/celerybeat-schedule" # Specify writable location for schedule file
    ]
    
    if platform.system() == "Windows":
        # Windows: Use subprocess to start background processes with visible logs
        subprocess.Popen(worker_cmd, cwd=backend_dir, env=env, # Pass the modified env
                        stdout=sys.stdout, stderr=sys.stderr,
                        creationflags=subprocess.CREATE_NEW_PROCESS_GROUP)
        subprocess.Popen(beat_cmd, cwd=backend_dir, env=env, # Pass the modified env
                        stdout=sys.stdout, stderr=sys.stderr,
                        creationflags=subprocess.CREATE_NEW_PROCESS_GROUP)
    else:
        # Linux/Mac: Use subprocess with visible logs
        subprocess.Popen(worker_cmd, cwd=backend_dir, env=env, # Pass the modified env
                        stdout=sys.stdout, stderr=sys.stderr)
        subprocess.Popen(beat_cmd, cwd=backend_dir, env=env, # Pass the modified env
                        stdout=sys.stdout, stderr=sys.stderr)
    
    print("Celery worker and beat scheduler started in background")
    time.sleep(2)  # Give Celery components time to start

if __name__ == "__main__":
    # Set the port for Hugging Face Spaces
    port = os.environ.get('PORT', '7860')
    os.environ.setdefault('PORT', port)
    
    print(f"Starting Lin application on port {port}...")
    print("=" * 60)
    
    # Check if Redis is available
    if not check_redis():
        print("Warning: Redis not available. Celery may not function properly.")
        print("Continuing with Flask app only...")
        print("=" * 60)
    
    try:
        # Start Celery components first
        start_celery_components()
        
        # Import and run the backend Flask app directly
        from backend.app import create_app
        app = create_app()
        
        print("=" * 60)
        print("Flask application starting...")
        print("Access the application at:")
        print(f"  http://localhost:{port}")
        print(f"  http://127.0.0.1:{port}")
        print("=" * 60)
        
        app.run(
            host='0.0.0.0',
            port=int(port),
            debug=False,
            threaded=True
        )
        
    except KeyboardInterrupt:
        print("\nShutting down application...")
        sys.exit(0)
    except Exception as e:
        print(f"Failed to start Lin application: {e}")
        import traceback
        traceback.print_exc()
        sys.exit(1)