PoC: Async Message Processing with WebSocket Communication

[VCauthon]

I'll create a simple demonstration project to understand asynchronous messaging with AWS.

Required AWS Resources:

• API Gateway (WebSocket API)
• SNS Topic (for message processing)
• SQS Queue (for responses)
• DynamoDB (to track connections)
• Lambda functions

Basic Flow:

1. Client connects via WebSocket
2. Client sends message
3. System processes message asynchronously
4. System sends response back through WebSocket

# connection_handler.py
import boto3
import os
import json

dynamodb = boto3.client('dynamodb')
CONNECTIONS_TABLE = os.environ['CONNECTIONS_TABLE']

def handle_connect(event, context):
    connection_id = event['requestContext']['connectionId']
    
    # Store connection ID
    dynamodb.put_item(
        TableName=CONNECTIONS_TABLE,
        Item={
            'connectionId': {'S': connection_id}
        }
    )
    
    return {'statusCode': 200}

# message_handler.py
import boto3
import json

sns = boto3.client('sns')
TOPIC_ARN = os.environ['TOPIC_ARN']

def handle_message(event, context):
    connection_id = event['requestContext']['connectionId']
    body = json.loads(event['body'])
    
    # Publish message to SNS
    message = {
        'connectionId': connection_id,
        'message': body['message']
    }
    
    sns.publish(
        TopicArn=TOPIC_ARN,
        Message=json.dumps(message)
    )
    
    return {'statusCode': 200}

# response_handler.py
import boto3
import json
import os

api_gateway = boto3.client('apigatewaymanagementapi')
sqs = boto3.client('sqs')
QUEUE_URL = os.environ['QUEUE_URL']

def process_responses(event, context):
    for record in event['Records']:
        message = json.loads(record['body'])
        connection_id = message['connectionId']
        
        # Send response back through WebSocket
        api_gateway.post_to_connection(
            ConnectionId=connection_id,
            Data=json.dumps({
                'message': message['response']
            })
        )

Key Implementation Steps:

1. Set up WebSocket API in API Gateway
2. Create DynamoDB table for connection tracking
3. Set up SNS topic and SQS queue
4. Create Lambda functions for handling:
   • WebSocket connections
   • Incoming messages
   • Processing responses
5. Configure IAM permissions
6. Implement client-side WebSocket handling

The key pattern here is:

• Asynchronous message processing through SNS/SQS
• WebSocket for real-time responses
• Connection tracking in DynamoDB

This creates a foundation for understanding the more complex chatbot implementation. Would you like me to elaborate on any part?