futured

Futured provides a consistent interface for concurrent functional programming in Python. It wraps any callable to return a concurrent.futures.Future, wraps any async coroutine with a compatible Task interface, and provides concurrent iterators and context managers for futures.

Usage

threaded, processed

Transform any callable into one which runs in a thread or process pool, and returns a future.

from futured import threaded, processed
import httpx

fetch = threaded(httpx.Client().get)
fetch(url)  # return Future

fs = (fetch(url + path) for path in paths)
threaded.results(fs)  # generate results from futures
threaded.results(fs, timeout=...)  # generate results as completed

fetch.map(urls)  # generate results in order
fetch.map(urls, timeout=...)  # generate results as completed
fetch.mapzip(urls)  # generate (url, result) pairs as completed

Thread and process pool executors may be used as context managers, customized with options, and reused with different callables.

threaded(max_workers=...)(func, ...)
processed(max_workers=...)(func, ...)

futured classes have a waiting context manager which collects results from tasks. Futures can be registered at creation, or appended to the list of tasks.

with threaded.waiting(*fs) as tasks:
    tasks.append(future)
tasks  # list of completed results

futured classes provide a tasks interface which generalizes futures.as_completed and futures.wait, while allowing the set of tasks to be modified, e.g., for retries.

threaded.tasks(fs, timeout=...)  # mutable set of running tasks which iterate as completed

asynced

The same interface works for asyncio.

from futured import asynced
import httpx

fetch = asynced(httpx.AsyncClient().get)
fetch(url)  # return coroutine

asynced.results(fs)  # generate results from futures
asynced.results(fs, timeout=...)  # generate results as completed

fetch.map(urls)  # generate results in order
fetch.map(urls, timeout=...)  # generate results as completed
fetch.mapzip(urls)  # generate (url, result) pairs as completed

asynced provides utilities for calling coroutines from a synchronous context. waiting is similar to trio's nursery, but returns results from a synchronous with block.

asynced.run(async_func, ...)  # call and run until complete
asynced.run(async_gen, ...)  # call and run synchronous iterator
with asynced.waiting(*fs) as tasks:  # concurrent coroutines completed in a block
asynced.tasks(fs, timeout=...)  # mutable set of running tasks which iterate as completed

extensions

There is also support for dask distributed clients and gevent greenlets.

from futured import distributed, greened

decorators

Naturally futured wrappers can be used as decorators, but arguments can also be partially bound.

@threaded
def slow():
   ...

fetch = threaded(httpx.Client().get, url)
fetch(params=...)

Methods are supported, as well as a decorated utility for automatically subclassing.

from futured import decorated

FutureClient = decorated(httpx.Client, request=threaded)

 # equivalent to
class FutureClient(httpx.Client):
    request = threaded(httpx.Client.request)

command

command wraps subprocess.Popen to provide a Future compatible interface.

from futured import futured, command

command('ls').result()  # return stdout or raises stderr
command('ls').pipe('wc')  # pipes into next command, or | ('wc',... )
for line in command('ls'):  # iterable lines
command.coroutine('ls')  # return coroutine

futured(command, 'ls')  # supports `map` interface
asynced(command.coroutine, 'ls')  # supports `map` interface with timeout

forked

forked allows iteration in separate child processes.

from futured import forked

for value in forked(values, max_workers=...):
    # in a child process
 # in parent after children have exited

Installation

% pip install futured

Tests

100% branch coverage.

% pytest [--cov]