Comprehensive comparison for DevOps technology in Software Development applications

import json
import boto3
import os
from datetime import datetime
from botocore.exceptions import ClientError
import logging

# Configure logging
logger = logging.getLogger()
logger.setLevel(logging.INFO)

# Initialize AWS clients
dynamodb = boto3.resource('dynamodb')
sns = boto3.client('sns')
cloudwatch = boto3.client('cloudwatch')

# Environment variables
TABLE_NAME = os.environ.get('ORDERS_TABLE', 'orders')
SNS_TOPIC_ARN = os.environ.get('SNS_TOPIC_ARN')

def lambda_handler(event, context):
    """
    Process order creation with DynamoDB storage, SNS notification,
    and CloudWatch metrics - Production DevOps pattern
    """
    try:
        # Parse and validate request body
        body = json.loads(event.get('body', '{}'))
        
        if not body.get('user_id') or not body.get('items'):
            return create_response(400, {'error': 'Missing required fields'})
        
        # Generate order ID and timestamp
        order_id = f"ORD-{datetime.utcnow().strftime('%Y%m%d%H%M%S')}-{body['user_id']}"
        timestamp = datetime.utcnow().isoformat()
        
        # Calculate total amount
        total_amount = sum(item.get('price', 0) * item.get('quantity', 0) 
                          for item in body['items'])
        
        # Prepare order item for DynamoDB
        order_item = {
            'order_id': order_id,
            'user_id': body['user_id'],
            'items': body['items'],
            'total_amount': total_amount,
            'status': 'pending',
            'created_at': timestamp,
            'updated_at': timestamp
        }
        
        # Store order in DynamoDB with conditional check
        table = dynamodb.Table(TABLE_NAME)
        table.put_item(
            Item=order_item,
            ConditionExpression='attribute_not_exists(order_id)'
        )
        
        logger.info(f"Order created successfully: {order_id}")
        
        # Send SNS notification for order processing pipeline
        if SNS_TOPIC_ARN:
            try:
                sns.publish(
                    TopicArn=SNS_TOPIC_ARN,
                    Message=json.dumps(order_item),
                    Subject=f"New Order: {order_id}",
                    MessageAttributes={
                        'order_id': {'DataType': 'String', 'StringValue': order_id},
                        'user_id': {'DataType': 'String', 'StringValue': body['user_id']}
                    }
                )
            except ClientError as e:
                logger.error(f"SNS publish failed: {str(e)}")
        
        # Publish custom CloudWatch metric
        cloudwatch.put_metric_data(
            Namespace='OrderService',
            MetricData=[
                {
                    'MetricName': 'OrdersCreated',
                    'Value': 1,
                    'Unit': 'Count',
                    'Timestamp': datetime.utcnow()
                },
                {
                    'MetricName': 'OrderValue',
                    'Value': total_amount,
                    'Unit': 'None',
                    'Timestamp': datetime.utcnow()
                }
            ]
        )
        
        return create_response(201, {
            'order_id': order_id,
            'status': 'pending',
            'total_amount': total_amount
        })
        
    except json.JSONDecodeError:
        logger.error("Invalid JSON in request body")
        return create_response(400, {'error': 'Invalid JSON'})
    
    except ClientError as e:
        logger.error(f"DynamoDB error: {str(e)}")
        if e.response['Error']['Code'] == 'ConditionalCheckFailedException':
            return create_response(409, {'error': 'Order already exists'})
        return create_response(500, {'error': 'Database error'})
    
    except Exception as e:
        logger.error(f"Unexpected error: {str(e)}")
        return create_response(500, {'error': 'Internal server error'})

def create_response(status_code, body):
    """Helper function to create API Gateway response"""
    return {
        'statusCode': status_code,
        'headers': {
            'Content-Type': 'application/json',
            'Access-Control-Allow-Origin': '*'
        },
        'body': json.dumps(body)
    }