Cache

Custom caches and utilities

class LRUCache(func: Callable, maxsize: int = 8)

Bases: object

Custom Least Recently Used (LRU) memory cache.

Parameters:

• func (class or func) -- Function result or class instantiation to be cached.

• maxsize (int, optional) -- Maximum size of the cache.

class LRUSharedRWCache(func: Callable, name: str | None = None, maxsize: int = 8, shared: bool = True, removecall: Callable | None = None, logger: Logger | None = None)

Bases: object

Custom, dictionary-based, Least Recently Used (LRU) reader-writer lockable cache, shareable across processes.

Parameters:

• func (Callable) -- Function to be cached.

• name (str, optional) -- Name of the lock cache.

• maxsize (int, optional) -- Maximum size of the cache.

• shared (bool, optional) -- Share dictionary across processes (requires POSIX IPC support)

• removecall (func, optional) -- Callback function for removing cached data.

• logger (logging.Logger, optional) -- Logger object to display cache handling information.

call_unshared(*args, **kwargs)

Get or recover a cached entry, not shared with other processes.

Parameters:

• args (any) -- Hashable arguments to the cache dictionary.

• kwargs (any) -- Hashable keyworded arguments to the cache dictionary.

Returns:

• result -- Cached output.

• lock -- Reader-Writer lock associated with args, set to None.

• msg -- "OK" or error string in case of an exception.

• :meta public:

call_shared(*args, **kwargs)

Get or recover a cached entry, not shared with other processes.

Parameters:

• args (any) -- Hashable arguments to the cache dictionary.

• kwargs (any) -- Hashable keyworded arguments to the cache dictionary.

Returns:

• result -- Cached output.

• lock -- Reader-Writer lock associated with args.

• msg -- "OK" or error string in case of an exception.

• :meta public:

remove(*args) → None

Remove semaphores.

class SharedRWLock(name: str = 'RWLock')

Bases: object

Custom reader-writer lock shareable across processes

See Raynal, Michel (2012), Concurrent Programming: Algorithms, Principles, and Foundations, Springer.

Parameters:

name (str, optional) -- Name of the lock.

acquire_read() → None

Acquire lock in read mode.

acquire_write() → None

Acquire lock in write mode.

release_read() → None

Release acquired read lock.

release_write() → None

Release acquired write lock.

remove(*args) → None

Remove files used by the RW lock semaphores and shared memory.