Source code for paco.times

# -*- coding: utf-8 -*-
import asyncio
from .decorator import decorate
from .assertions import assert_corofunction

ExceptionMessage = 'paco: coroutine cannot be executed more than {} times'

[docs]@decorate def times(coro, limit=1, raise_exception=False, return_value=None): """ Wraps a given coroutine function to be executed only a certain amount of times. If the execution limit is exceeded, the last execution return value will be returned as result. You can optionally define a custom return value on exceeded via `return_value` param. This function can be used as decorator. arguments: coro (coroutinefunction): coroutine function to wrap. limit (int): max limit of coroutine executions. raise_exception (bool): raise exception if execution times exceeded. return_value (mixed): value to return when execution times exceeded. Raises: TypeError: if coro argument is not a coroutine function. RuntimeError: if max execution excedeed (optional). Returns: coroutinefunction Usage:: async def mul_2(num): return num * 2 timed = paco.times(mul_2, 3) await timed(2) # => 4 await timed(3) # => 6 await timed(4) # => 8 await timed(5) # ignored! # => 8 """ assert_corofunction(coro=coro) # Store call times limit = max(limit, 1) times = limit # Store result from last execution result = None @asyncio.coroutine def wrapper(*args, **kw): nonlocal limit nonlocal result # Check execution limit if limit == 0: if raise_exception: raise RuntimeError(ExceptionMessage.format(times)) if return_value: return return_value return result # Decreases counter limit -= 1 # If return_value is present, do not memoize result if return_value: return (yield from coro(*args, **kw)) # Schedule coroutine and memoize result result = yield from coro(*args, **kw) return result return wrapper