Source code for paco.each

# -*- coding: utf-8 -*-
import asyncio
from .decorator import overload
from .concurrent import ConcurrentExecutor, safe_run
from .assertions import assert_corofunction, assert_iter

[docs]@overload @asyncio.coroutine def each(coro, iterable, limit=0, loop=None, collect=False, timeout=None, return_exceptions=False, *args, **kw): """ Concurrently iterates values yielded from an iterable, passing them to an asynchronous coroutine. You can optionally collect yielded values passing collect=True param, which would be equivalent to ```. Mapped values will be returned as an ordered list. Items order is preserved based on origin iterable order. Concurrency level can be configurable via `limit` param. All coroutines will be executed in the same loop. This function is a coroutine. This function can be composed in a pipeline chain with ``|`` operator. Arguments: coro (coroutinefunction): coroutine iterator function that accepts iterable values. iterable (iterable|asynchronousiterable): an iterable collection yielding coroutines functions. limit (int): max iteration concurrency limit. Use ``0`` for no limit. collect (bool): return yielded values from coroutines. Default False. loop (asyncio.BaseEventLoop): optional event loop to use. return_exceptions (bool): enable/disable returning exceptions in case of error. `collect` param must be True. timeout (int|float): timeout can be used to control the maximum number of seconds to wait before returning. timeout can be an int or float. If timeout is not specified or None, there is no limit to the wait time. *args (mixed): optional variadic arguments to pass to the coroutine iterable function. Returns: results (list): ordered list of values yielded by coroutines Raises: TypeError: in case of invalid input arguments. Usage:: async def mul_2(num): return num * 2 await paco.each(mul_2, [1, 2, 3, 4, 5]) # => None await paco.each(mul_2, [1, 2, 3, 4, 5], collect=True) # => [2, 4, 6, 8, 10] """ assert_corofunction(coro=coro) assert_iter(iterable=iterable) # By default do not collect yielded values from coroutines results = None if collect: # Store ordered results results = [None] * len(iterable) # Create concurrent executor pool = ConcurrentExecutor(limit=limit, loop=loop) @asyncio.coroutine def collector(index, item): result = yield from safe_run(coro(item, *args, **kw), return_exceptions=return_exceptions) if collect: results[index] = result return result # Iterate and pass elements to coroutine for index, value in enumerate(iterable): pool.add(collector(index, value)) # Wait until all the coroutines finishes yield from, ignore_empty=True, timeout=timeout) # Returns list of mapped results in order return results