Library to "watch" files in a directory and call a callback function (filename, lines) every time one of the monitored files is recorded, in real time.

In practical terms, this can be compared to UNIX's tail -F * .log command, but instead of having lines printed in stdout, a Python function is called.

Like tail, it is in charge of "watching" new files that are created after startup and "unlock" those that are removed in the meantime. This means that you will be able to "follow" and support rotating log files as well.

Key Features

• Uses Asyncio for asynchronous reading and monitoring.
• The implementation chooses automatically depending on the compatibility of the system.
• Monitoring of several files in the same directory or just one.
• Asynchronous callback function.

Getting started

All code samples require Python 3.6+.

Basic Usage

import asyncio
from aiowatcher import AIOWatcher

async def callback(filename, line):
    print(line)

async def main():
    lw = AIOWatcher('var', callback, extensions=['txt'])
    await lw.init()
    await lw.loop()

loop = asyncio.get_event_loop()
loop.run_until_complete(main())    

Non blocking

import asyncio
from aiowatcher import AIOWatcher

async def callback(filename, line):
    print(line)

async def main():
    lw = AIOWatcher('var', callback, extensions=['txt'])
    while True:
        await lw.loop(blocking=False)
        await asyncio.sleep(0.1)

loop = asyncio.get_event_loop()
loop.run_until_complete(main())

Tail

import asyncio
from aiowatcher import AIOWatcher

async def callback(filename, lines):
    for line in lines:
        print(line[:-1])

async def main():
    lw = AIOWatcher('var', callback, extensions=['txt'])
    await lw.tail(3)

loop = asyncio.get_event_loop()
loop.run_until_complete(main())

License

aiowatcher is offered under the Apache 2 license.

Source code

The latest version of the developer is available on a GitHub repository: https://github.com/py-paulo/aiowatcher.git

Changelog

0.0.5 (22-09-2020)

Features

• new AIOWatcher().tail function to read N lines from a file and return as list.

Bugfixes

• AIOWatcher.readlines() returns a list instead of a string.