crhelper

import logging import os from crhelper import CfnResource logger = logging.getLogger(__name__) # Initialise the helper, all inputs are optional helper = CfnResource(json_logging=True, log_level='INFO', boto_level='CRITICAL') # Example function to be called by the helper @helper.create @helper.update def create_update_resource(event, context): logger.info("Got Create/Update event") # Access properties from the CloudFormation event my_property = event['ResourceProperties'].get('MyProperty', 'default') logger.info(f"MyProperty: {my_property}") # Simulate creating/updating a resource physical_resource_id = f"my-custom-resource-{my_property}" # Optionally return an ID that will be used for the PhysicalResourceId # if None is returned, an ID will be generated. The value is used in subsequent Update/Delete events. helper.Data['Result'] = 'Success' return physical_resource_id @helper.delete def delete_resource(event, context): logger.info("Got Delete event") # Access the PhysicalResourceId of the resource to be deleted physical_resource_id = event.get('PhysicalResourceId') logger.info(f"Deleting resource: {physical_resource_id}") # Simulate deleting the resource # No return value needed for delete def handler(event, context): logger.info("Lambda handler invoked") helper(event, context) # Example of how to run this locally for testing purposes (outside Lambda) if __name__ == '__main__': # Mock event and context for local testing mock_event = { 'RequestType': 'Create', 'ResponseURL': 'http://example.com/', 'StackId': 'arn:aws:cloudformation:us-east-1:123456789012:stack/MyStack/UUID', 'RequestId': 'uniqueid123', 'LogicalResourceId': 'MyCustomResource', 'ResourceType': 'Custom::MyResource', 'ResourceProperties': { 'ServiceToken': 'arn:aws:lambda:us-east-1:123456789012:function:my-cr-lambda', 'MyProperty': 'test-value' } } mock_context = type('Context', (object,), { 'function_name': 'test-func', 'invoked_function_arn': 'arn:aws:lambda:us-east-1:123456789012:function:test-func', 'aws_request_id': 'reqid123', 'log_group_name': '/aws/lambda/test-func', 'log_stream_name': '2026/04/14/[$LATEST]uuid', 'memory_limit_in_mb': '128', 'get_remaining_time_in_millis': lambda: 60000 # Mock 60 seconds remaining })() print("--- Simulating Create Event ---") # In a real scenario, helper would send response to ResponseURL # For local test, we just call the handler and check logs handler(mock_event, mock_context) print("\n--- Simulating Update Event ---") mock_event['RequestType'] = 'Update' mock_event['PhysicalResourceId'] = 'my-custom-resource-test-value' # Must be present for Update/Delete handler(mock_event, mock_context) print("\n--- Simulating Delete Event ---") mock_event['RequestType'] = 'Delete' handler(mock_event, mock_context)