Implement Zero-Downtime Model Swaps for Industrial AI with Seldon Core and vLLM

"""
Production implementation for zero-downtime model swaps in industrial AI.
Provides secure, scalable operations using Seldon Core and vLLM.
"""
from typing import Dict, Any, List
import os
import logging
import time
import requests
from contextlib import contextmanager

# Setting up logging for the application
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class Config:
    """
    Configuration class to manage environment variables.
    """
    model_url: str = os.getenv('MODEL_URL')
    max_retries: int = int(os.getenv('MAX_RETRIES', 3))

@contextmanager
def connection_pool():
    """Context manager for managing connections.
    
    Yields a dummy connection for illustrative purposes.
    """
    try:
        # Simulate connection establishment
        logger.info('Establishing connection pool.')
        yield 'dummy_connection'
    finally:
        logger.info('Closing connection pool.')

async def validate_input(data: Dict[str, Any]) -> bool:
    """Validate request data.
    
    Args:
        data: Input to validate
    Returns:
        True if valid
    Raises:
        ValueError: If validation fails
    """
    if 'model_name' not in data:
        raise ValueError('Missing model_name in request data')
    return True

async def fetch_current_model() -> str:
    """Fetch the current model from Seldon Core.
    
    Returns:
        Current model name
    Raises:
        RuntimeError: If fetching fails
    """
    response = requests.get(f'{Config.model_url}/current')
    if response.status_code != 200:
        raise RuntimeError('Failed to fetch current model')
    return response.json()['model_name']

async def swap_model(new_model: str) -> None:
    """Swap the model in Seldon Core.
    
    Args:
        new_model: The name of the new model to deploy
    Raises:
        RuntimeError: If swapping fails
    """
    response = requests.post(f'{Config.model_url}/swap', json={'model_name': new_model})
    if response.status_code != 200:
        raise RuntimeError('Failed to swap model')
    logger.info(f'Model swapped to {new_model}')

async def process_model_swap(data: Dict[str, Any]) -> None:
    """Main workflow for processing the model swap.
    
    Args:
        data: Input data containing model details
    """
    try:
        await validate_input(data)  # Validate input data
        current_model = await fetch_current_model()  # Fetch current model
        logger.info(f'Current model is: {current_model}')  # Log current model
        await swap_model(data['model_name'])  # Swap to new model
    except Exception as e:
        logger.error(f'Error during model swap: {str(e)}')  # Log error

async def handle_request(request_data: Dict[str, Any]) -> None:
    """Handle incoming requests for model swaps.
    
    Args:
        request_data: Incoming request data
    """
    retries = 0
    while retries < Config.max_retries:
        try:
            await process_model_swap(request_data)  # Process the model swap
            break  # Exit loop on success
        except Exception as e:
            retries += 1
            logger.warning(f'Attempt {retries}: {str(e)}')  # Log warning on retry
            time.sleep(2 ** retries)  # Exponential backoff
    else:
        logger.error('Max retries reached, model swap failed.')  # Log failure

if __name__ == '__main__':
    # Example usage
    sample_data = {'model_name': 'vLLM_Model_v2'}
    import asyncio
    asyncio.run(handle_request(sample_data))