paco

Small utility library for coroutine-driven asynchronous generic programming in Python

202

Python

paco |PyPI| |Coverage Status| |Documentation Status| |Stability| |Quality| |Versions|

Small and idiomatic utility library for coroutine-driven asynchronous generic programming in Python.

Built on top of asyncio, paco provides missing capabilities from Python stdlib
in order to write asynchronous cooperative multitasking in a nice-ish way.
Also, paco aims to port some of functools and itertools_ standard functions to the asynchronous world.

paco can be your utility belt to deal with asynchronous, I/O-bound, non-blocking concurrent code in a cleaner and idiomatic way.

Features

Simple and idiomatic API, extending Python stdlib with async coroutines gotchas.
Built-in configurable control-flow concurrency support (throttle).
No fancy abstractions: it just works with the plain asynchronous coroutines.
Useful iterables, decorators, functors and convenient helpers.
Coroutine-based functional helpers: compose, throttle, partial, timeout, times, until, race…
Asynchronous coroutines port of Python built-in functions: filter, map, dropwhile, filterfalse, reduce…
Supports asynchronous iterables and generators (PEP0525_)
Concurrent iterables and higher-order functions.
Better asyncio.gather() and asyncio.wait() with optional concurrency control and ordered results.
Works with both async/await_ and yield from_ coroutines syntax.
Reliable coroutine timeout limit handler via context manager.
Designed for intensive I/O bound concurrent non-blocking tasks.
Good interoperability with asyncio and Python stdlib functions.
Composable pipelines_ of functors via | operator overloading.
Small and dependency free.
Compatible with Python +3.4.

Installation

Using pip package manager:

… code-block:: bash

pip install --upgrade paco

Or install the latest sources from Github:

… code-block:: bash

pip install -e git+git://github.com/h2non/paco.git#egg=paco

API

paco.ConcurrentExecutor_
paco.apply_
paco.compose_
paco.concurrent_
paco.constant_
paco.curry_
paco.defer_
paco.dropwhile_
paco.each_
paco.every_
paco.filter_
paco.filterfalse_
paco.flat_map_
paco.gather_
paco.identity_
paco.interval_
paco.map_
paco.once_
paco.partial_
paco.race_
paco.reduce_
paco.repeat_
paco.run_
paco.series_
paco.some_
paco.throttle_
paco.thunk_
paco.timeout_
paco.TimeoutLimit_
paco.times_
paco.until_
paco.wait_
paco.whilst_
paco.wraps_

Examples
^^^^^^^^

Asynchronously and concurrently execute multiple HTTP requests.

… code-block:: python

import paco
import aiohttp

async def fetch(url):
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as res:
            return res

async def fetch_urls():
    urls = [
        'https://www.google.com',
        'https://www.yahoo.com',
        'https://www.bing.com',
        'https://www.baidu.com',
        'https://duckduckgo.com',
    ]

    # Map concurrent executor with concurrent limit of 3
    responses = await paco.map(fetch, urls, limit=3)

    for res in responses:
        print('Status:', res.status)

# Run in event loop
paco.run(fetch_urls())

Concurrent pipeline-style composition of transform functors over an iterable object.

… code-block:: python

import paco

async def filterer(x):
    return x < 8

async def mapper(x):
    return x * 2

async def drop(x):
    return x < 10

async def reducer(acc, x):
    return acc + x

async def task(numbers):
    return await (numbers
                   | paco.filter(filterer)
                   | paco.map(mapper)
                   | paco.dropwhile(drop)
                   | paco.reduce(reducer, initializer=0))

# Run in event loop
number = paco.run(task((1, 2, 3, 4, 5, 6, 7, 8, 9, 10)))
print('Number:', number) # => 36

License

MIT - Tomas Aparicio

… _asynchronous: http://python.org
… _asyncio: https://docs.python.org/3.5/library/asyncio.html
… _Python: http://python.org
… _annotated API reference: https://h2non.github.io/paco
… _async/await: https://www.python.org/dev/peps/pep-0492/
… _yield from: https://www.python.org/dev/peps/pep-0380/
… _Composable pipelines: #examples
… _itertools: https://docs.python.org/3/library/itertools.html
… _functools: https://docs.python.org/3/library/functools.html
… _PEP0525: https://www.python.org/dev/peps/pep-0525/

… |PyPI| image:: https://img.shields.io/pypi/v/paco.svg?maxAge=2592000?style=flat-square
:target: https://pypi.python.org/pypi/paco
… |Coverage Status| image:: https://coveralls.io/repos/github/h2non/paco/badge.svg?branch=master
:target: https://coveralls.io/github/h2non/paco?branch=master
… |Documentation Status| image:: https://img.shields.io/badge/docs-latest-green.svg?style=flat
:target: http://paco.readthedocs.io/en/latest/?badge=latest
… |Quality| image:: https://codeclimate.com/github/h2non/paco/badges/gpa.svg
:target: https://codeclimate.com/github/h2non/paco
… |Stability| image:: https://img.shields.io/pypi/status/paco.svg
:target: https://pypi.python.org/pypi/paco
… |Versions| image:: https://img.shields.io/pypi/pyversions/paco.svg
:target: https://pypi.python.org/pypi/paco