What ways of implementing idempotent operations do you know in Python?

Idempotent operations are operations that can be performed multiple times in succession without changing the result after the first call. In Python, the following approaches are often used to implement idempotency:

1. Checking the state before execution — before performing the operation, it is checked whether this step has already been completed. For example, if a function creates a file, it first checks whether the file exists.

import os

def create_file_idempotent(path):
    if not os.path.exists(path):
        with open(path, 'w') as f:
            f.write('data')
    # If the file already exists, do nothing

2. Using unique identifiers (e.g., UUIDs or hashes) — on repeated calls with the same identifier, the operation is not repeated.

3. Storing the state or result of the operation — for example, caching the result so that on a repeated call, the saved result is returned without re-executing.

4. Using atomic operations and transactions — especially when working with databases, to ensure that the operation either completes fully or not at all.

5. Functional programming style — functions without side effects are inherently idempotent.

Thus, idempotency is achieved through state control, request uniqueness, and preventing repeated data modification.