Async Function Tools

apartial(coro, *args, **kwargs)

Wraps a coroutine function with pre-defined arguments (including keyword arguments). It is an asynchronous version of functools.partial().

lru_cache(maxsize: int = 128, typed: bool = False, expire_after: Optional[float] = None)

A simple LRU cache just like functools.lru_cache(), but it works for coroutines. This is not as heavily optimized as functools.lru_cache() which uses an internal C implementation, as it targets async operations that take a long time.

It follows the same API that the standard functools provides. The wrapped function has cache_clear() method to flush the cache manually, but leaves cache_info() for statistics unimplemented.

Note that calling the coroutine multiple times with the same arguments before the first call returns may incur duplicate executions.

This function is not thread-safe.

Parameters

• maxsize – The maximum number of cached entries.

• typed – Cache keys in different types separately (e.g., 3 and 3.0 will be different keys).

• expire_after – Re-calculate the value if the configured time has passed even when the cache is hit. When re-calculation happens the expiration timer is also reset.