Erste Lambda Function (Python)

Welcome to AWS Lambda!

Why Python for Lambda?

The Lambda Handler Function

Your First Python Lambda

import json

def lambda_handler(event, context):
    # Your function's logic goes here
    message = "Hello from your first Lambda!"
    
    # Lambda functions typically return a dictionary
    return {
        'statusCode': 200,
        'body': json.dumps(message)
    }

# This block allows you to test your function locally
if __name__ == "__main__":
    # Simulate an empty event and context for a simple test
    mock_event = {}
    mock_context = None
    response = lambda_handler(mock_event, mock_context)
    print("Local Test Response:", response)

Understanding the 'event'

Code: Reading from the Event

import json

def lambda_handler(event, context):
    # Get 'name' from the event, or default to 'there'
    name = event.get('name', 'there') 
    message = f"Hello, {name} from Lambda!"
    
    return {
        'statusCode': 200,
        'body': json.dumps(message)
    }

# Local testing with different events
if __name__ == "__main__":
    mock_event_with_name = {"name": "CoddyKit User"}
    response_with_name = lambda_handler(mock_event_with_name, None)
    print("With name:", response_with_name)

    mock_event_no_name = {}
    response_no_name = lambda_handler(mock_event_no_name, None)
    print("Without name:", response_no_name)

The 'context' Object

Returning a Standard Response

Code: Complete API Response

import json

def lambda_handler(event, context):
    name = event.get('name', 'World')
    
    # Simulate a context object for local testing
    request_id = getattr(context, 'aws_request_id', 'local-test-id')

    response_message = f"Greetings, {name}! Your request ID is {request_id}."

    return {
        'statusCode': 200,
        'headers': {
            'Content-Type': 'application/json'
        },
        'body': json.dumps({
            'message': response_message,
            'input_data': event # Echoing input for demonstration
        })
    }

# Local testing with a dummy context
if __name__ == "__main__":
    class MockContext:
        aws_request_id = 'mock-request-123'

    mock_event = {"name": "CoddyKit"}
    mock_context_obj = MockContext()
    response = lambda_handler(mock_event, mock_context_obj)
    print("Full API Response:", response)

How Lambda Executes Your Code

Quick Check

Recap: Your First Lambda!