What are decorator factories and how to create them?

Question

Accepted Answer

**Decorator factory** is a function that **returns a decorator**. Allows passing arguments to decorators.

```python
import functools
import time

# Three levels of nesting
def retry(max_attempts=3, delay=1):
    def decorator(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            for attempt in range(max_attempts):
                try:
                    return func(*args, **kwargs)
                except Exception as e:
                    if attempt == max_attempts - 1:
                        raise
                    print(f"Retry {attempt + 1}/{max_attempts}")
                    time.sleep(delay)
        return wrapper
    return decorator

@retry(max_attempts=5, delay=2)
def unstable_function():
    import random
    if random.random() < 0.7:
        raise ConnectionError("Network error")
    return "Success"
```

**Popular examples:**
- `@lru_cache(maxsize=128)`.
- `@login_required(redirect_url="/login")`.
- `@validate(schema=MySchema)`.
- `@timer(unit="ms")`.

Python: What are decorator factories and how to create them?