Python lru_cache with timeout

timed_cache.py

from datetime import datetime, timedelta
import functools


def timed_cache(**timedelta_kwargs):                                              
                                                                                  
    def _wrapper(f):                                                              
        update_delta = timedelta(**timedelta_kwargs)                              
        next_update = datetime.utcnow() + update_delta                            
        # Apply @lru_cache to f with no cache size limit                          
        f = functools.lru_cache(None)(f)                                          
                                                                                                                      
        @functools.wraps(f)                                                       
        def _wrapped(*args, **kwargs):                                            
            nonlocal next_update                                                  
            now = datetime.utcnow()                                               
            if now >= next_update:                                                
                f.cache_clear()                                                   
                next_update = now + update_delta                                
            return f(*args, **kwargs)                                             
        return _wrapped                                                           
    return _wrapper

Thanks guys ! Btw it can leads to a TypeError: unhashable type: 'list' if you have list args. A fix could be to cast those args to tuple (more info : https://stackoverflow.com/a/49210802) This piece of code will fix this :

for arg, value in kwargs.items():
    kwargs[arg] = tuple(value) if type(value) == list else value

The behavior remains the same but I would suggest to use isinstance() instead of type()

for arg, value in kwargs.items():
    kwargs[arg] = tuple(value) if isinstance(value, list) else value

Thanks for the implementations! Really helpful!

Something I noticed is that neither of these implementations work with pytest-antilru. This is likely due to the lru_cache which is monkeypatched is not patched early enough: ipwnponies/pytest-antilru#28.

args = [tuple(v) if isinstance(v, list) else v for v in args]

for args too

Thanks guys ! Btw it can leads to a TypeError: unhashable type: 'list' if you have list args. A fix could be to cast those args to tuple (more info : https://stackoverflow.com/a/49210802) This piece of code will fix this :

for arg, value in kwargs.items():
    kwargs[arg] = tuple(value) if type(value) == list else value

The behavior remains the same but I would suggest to use isinstance() instead of type()

for arg, value in kwargs.items():
    kwargs[arg] = tuple(value) if isinstance(value, list) else value