Write Factory CDC Streams to Delta Lake with Bytewax and

                      
                     
"""
Production implementation for writing Factory CDC Streams to Delta Lake using Bytewax and Delta-rs.
Provides secure, scalable operations for real-time data processing.
"""

from typing import Dict, Any, List, Optional
import os
import logging
import time
import requests
from bytewax import Dataflow, run
from delta import DeltaTable

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

class Config:
    """
    Configuration class for environment variables.
    Stores necessary configuration for database connections and API endpoints.
    """
    delta_table_path: str = os.getenv('DELTA_TABLE_PATH')
    api_endpoint: str = os.getenv('API_ENDPOINT')

async def validate_input(data: Dict[str, Any]) -> bool:
    """Validate input data for CDC stream.
    
    Args:
        data: Input data from CDC stream
    Returns:
        True if valid
    Raises:
        ValueError: If validation fails
    """
    if 'id' not in data or 'operation' not in data:
        raise ValueError('Missing id or operation in input data')
    return True

async def sanitize_fields(data: Dict[str, Any]) -> Dict[str, Any]:
    """Sanitize input fields to prevent injection attacks.
    
    Args:
        data: Raw input data from CDC stream
    Returns:
        Sanitized data
    """
    return {key: str(value).strip() for key, value in data.items()}

async def transform_records(records: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
    """Transform raw records into a format suitable for Delta Lake.
    
    Args:
        records: List of raw records
    Returns:
        Transformed records
    """
    return [{'id': record['id'], 'value': record['value']} for record in records]

async def process_batch(batch: List[Dict[str, Any]]) -> None:
    """Process a batch of records and write to Delta Lake.
    
    Args:
        batch: List of records to process
    """
    for record in batch:
        try:
            await validate_input(record)
            sanitized_record = await sanitize_fields(record)
            # Here we would write the sanitized record to Delta Lake
            logger.info(f'Processing record: {sanitized_record}')
        except ValueError as e:
            logger.error(f'Validation error: {e}')

async def fetch_data() -> List[Dict[str, Any]]:
    """Fetch data from the CDC stream API.
    
    Returns:
        List of records from CDC stream
    Raises:
        Exception: If API request fails
    """
    try:
        response = requests.get(Config.api_endpoint)
        response.raise_for_status()  # Raise an error for bad responses
        return response.json()
    except requests.RequestException as e:
        logger.error(f'Error fetching data: {e}')
        raise

async def save_to_db(records: List[Dict[str, Any]]) -> None:
    """Save processed records to Delta Lake.
    
    Args:
        records: List of records to save
    """
    delta_table = DeltaTable.for_path(Config.delta_table_path)
    for record in records:
        # Here we would append the record to the Delta Lake table
        delta_table.insert(record)
        logger.info(f'Record saved: {record}')

async def call_api(data: Dict[str, Any]) -> None:
    """Call external API with data.
    
    Args:
        data: Data to send to API
    """
    try:
        response = requests.post(Config.api_endpoint, json=data)
        response.raise_for_status()
        logger.info('Data sent to API successfully')
    except requests.RequestException as e:
        logger.error(f'Error calling API: {e}')

async def format_output(data: Dict[str, Any]) -> str:
    """Format data for output.
    
    Args:
        data: Data to format
    Returns:
        Formatted string output
    """
    return str(data)

class CDCProcessor:
    """Main orchestrator for processing CDC streams to Delta Lake.
    """
    def __init__(self):
        self.delta_table_path = Config.delta_table_path

    async def run(self) -> None:
        """Execute the data processing workflow.
        """
        while True:
            try:
                raw_data = await fetch_data()
                transformed_data = await transform_records(raw_data)
                await process_batch(transformed_data)
                await save_to_db(transformed_data)
            except Exception as e:
                logger.error(f'Error in processing: {e}')
                time.sleep(5)  # Simple backoff strategy

if __name__ == '__main__':
    # Example usage
    processor = CDCProcessor()
    run(processor.run())