Importance of Filelock and how to use that in Python

We need the filelock module in Python to prevent race conditions in concurrent and multi-process applications. Race conditions occur when multiple processes or threads access the same resource simultaneously and the outcome of the application depends on which process finishes first.

For example, consider a scenario where multiple processes write to the same file. If two processes try to write to the file simultaneously, the second process may overwrite the changes made by the first process, leading to data corruption and incorrect results.

To install filelock

pip install filelock

Simple Example of filelock module to lock a file in Python:

import os
from filelock import Filelock

lock = FileLock("file.lock")

with lock:
    with open("file.txt", "a") as f:
        f.write(f"Line written by process { os.getpid()}\n")

Here, You can name your lockfile anything you want, in our case, it is file.lock. This file will temporally create while acquiring the lock and it will automatically deleted after releasing the lock.
we use the FileLock class from the filelock module to lock the file file.lock. The with statement is used to obtain the lock and automatically release it after the protected code has executed. This ensures that only one process can access the file at a time and prevents race conditions.

The os.getpid() function is used to obtain the process ID, which is written to the file along with the line of text. This allows us to see which process wrote each line to the file.

Summary

The filelock module provides a simple and reliable way to lock files and prevent race conditions. By using a lock file, you can ensure that only one process can access a shared resource at a time, and prevent data corruption and other issues that can occur when multiple processes access the same resource simultaneously. The filelock module is a great tool for developing concurrent and multi-process applications in Python, and it provides a simple and reliable way to lock files and prevent race conditions.

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