logbook-aiopipe 0.2.0

Multiprocess logbook logging for asyncio

logbook_aiopipe -- Multiprocess logbook logging for asyncio

Documentation

This package provides a handler and subscriber for multiprocess logbook logging that runs on the asyncio event loop. It uses aiopipe to transfer log messages from the child process to the parent process.

Example

The following example shows a typical application of multiprocess logging. It results in two log messages, hello from parent process and hello from child process, being printed in some order.

from contextlib import closing
from multiprocessing import Process
import asyncio

from aiopipe import aiopipe
from logbook_aiopipe import AioPipeSubscriber, \
        AioPipeHandler
from logbook import Logger, StderrHandler

async def mainTask(eventLoop):
    # The parent process logger can be set up as normal.
    log = Logger()
    log.handlers.append(StderrHandler())

    rx, tx = aiopipe()
    sub = AioPipeSubscriber(await rx.open(eventLoop), log)

    with closing(sub):
        subTask = eventLoop.create_task(sub.run())

        with tx.send() as tx:
            proc = Process(target=childProc, args=(tx,))
            proc.start()

        log.info("hello from parent process")

        proc.join()
        await subTask

def childProc(tx):
    eventLoop = asyncio.new_event_loop()
    eventLoop.run_until_complete(childTask(eventLoop, tx))

async def childTask(eventLoop, tx):
    log = Logger()

    # The child process should use only `AioPipeHandler` as
    # its handler.
    handler = AioPipeHandler(await tx.open(eventLoop))
    log.handlers.append(handler)

    with closing(handler):
        log.info("hello from child process")

eventLoop = asyncio.get_event_loop()
eventLoop.run_until_complete(mainTask(eventLoop))

Installation

This package requires Python >= 3.5.0 and can be installed with pip:

pip install logbook_aiopipe