Скачать или смотреть How to Effectively Terminate Bash Scripts and Background Jobs with Python's subprocess Module

Learn how to properly kill a Bash script and its background processes when using subprocess.Popen in Python. This guide provides clear solutions and explanations about managing processes.
---
This video is based on the question https://stackoverflow.com/q/65735724/ asked by the user 'maydin' ( https://stackoverflow.com/u/5537887/ ) and on the answer https://stackoverflow.com/a/65764728/ provided by the user 'maydin' ( https://stackoverflow.com/u/5537887/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: subprocess.Popen("bash file.sh"): how to kill the Bash script and all its background jobs

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Effectively Terminate Bash Scripts and Background Jobs with Python's subprocess Module

Running scripts and managing processes can be a complex task when working with different programming environments. If you've ever tried to manage background processes initiated by a Bash script from a Python script using the subprocess module, you may have encountered the challenge of terminating those processes effectively. In this guide, we’ll explore how to resolve this issue step-by-step, allowing you to kill your Bash scripts and all associated background jobs smoothly.

Understanding the Problem

When you run a Bash script directly in a terminal, you can easily interrupt execution using Ctrl-C, which sends a termination signal to all processes started by that script. However, this behavior doesn't mimic itself when we start the bash script from a Python script using the subprocess.Popen() command. It can be frustrating when you can terminate your primary script, but the background jobs continue to run undisturbed.

Scenario Overview

Consider a simple Bash script that pings two servers concurrently:

[[See Video to Reveal this Text or Code Snippet]]

If you run this script directly in the command line, you can stop both pings by hitting Ctrl-C. But what happens when you invoke it using a Python script like this:

[[See Video to Reveal this Text or Code Snippet]]

The send_signal does not effectively terminate the background jobs started by the Bash script. At this point, you might be wondering how to resolve this issue.

The Solution

To effectively manage the termination of a Bash script and its child processes, we need to implement a proper termination strategy within the Bash script itself. Here’s how to do it:

Step 1: Modify the Bash Script

You need to add a function in your Bash script. This function will help in handling termination signals and ensuring all child processes are killed when the script is terminated. Add the following code before the wait line:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Send the Right Signal from Python

In your Python script, it's crucial to utilize the signal-handling methods effectively. Make sure that when you wish to terminate your script, you send the SIGTERM signal instead of SIGINT. To do this, you can replace the send_signal line with:

[[See Video to Reveal this Text or Code Snippet]]

Complete Python Example

Here's how your final Python script would look:

[[See Video to Reveal this Text or Code Snippet]]

Summary

By implementing these steps, you can effectively terminate both the Bash script and its background jobs when using Python's subprocess module. This method enhances the management of processes, ensuring that you maintain control over the execution flow of your scripts.

Modify your Bash script to handle SIGTERM properly.

Send the right signal from Python using SIGTERM.

With these adjustments, you'll find that controlling your scripts and background processes becomes a much smoother experience. Happy coding!