How did you achieve idempotency?

Idempotency is a property of an operation where repeated execution with the same input data does not change the result after the first call.

In Python, several approaches can be used to achieve idempotency:

• State check before execution: for example, check if a record already exists before creating it.
• Use of unique identifiers (idempotency keys): with repeated requests using the same key, the operation is not performed again.
• Exception handling and retries while preserving the result.

An example using a dictionary to store already processed requests:

processed_requests = {}

def process_request(request_id, data):
    if request_id in processed_requests:
        return processed_requests[request_id]  # Return the stored result
    # Processing logic
    result = data * 2  # example processing
    processed_requests[request_id] = result
    return result

Thus, a repeated call with the same request_id will not change the state and will return the same result.