Скачать или смотреть How to Run Multiple Python Scripts in a Bash Script within Docker

Learn how to run multiple Python scripts simultaneously in a Bash script executed from a Docker container. This guide provides step-by-step instructions and considerations for beginners.
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Running Multiple Python Scripts in a Bash Script within Docker

Are you trying to run multiple Python scripts at the same time using a bash script in a Docker environment? If you've attempted this and found that your application isn’t working as intended, you're not alone. Many developers encounter issues when they try to manage background processes effectively in shell scripts, especially when Docker is involved.

In this post, let's dive into how to successfully execute two Python scripts together within a bash script running in a Docker container. We'll break down the solution into digestible sections for better understanding.

Problem Overview

In your scenario, you have two Python scripts: main.py, which serves as an app server, and service_scheduler.py, which is designed to run a job at regular intervals. However, when you added service_scheduler.py to your bash script (svc_invoke.sh), neither script executed properly, causing the desired scheduling not to take place.

Initial Script

Your initial bash script looked like this:

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

This script launches both Python scripts in the background but fails to handle their execution properly. As a result, Docker may terminate before these scripts have a chance to finish.

Solution: Using wait Command

To rectify this issue, you need to ensure that your script waits for both Python processes to complete before it exits. This can be achieved using the wait command. Here’s how you should structure your bash script:

Revised Script

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

Key Changes Explained

Background Execution with &: Both scripts are still run in the background using &, but we save their process IDs ($!) into variables (mainpid and schedpid).

Using wait: The wait command is employed to pause the execution of the script until each of the Python processes completes. This prevents the Docker container from terminating prematurely.

Status Checks: After each wait, we check for any errors by capturing the exit status ($?). If either script fails, a message is logged, and the script exits with a corresponding status.

Conclusion

By modifying your initial bash script to include process handling with wait, you can effectively run multiple Python scripts concurrently in a Docker environment. This adjustment not only ensures that both your application server and the scheduler run correctly but also helps maintain control over the processes within your Docker container.

If you're new to Docker and shell scripting, don't hesitate to practice with these concepts and refer back to this guide when needed. Running multiple scripts concurrently can enhance the efficiency of your applications, allowing you to manage tasks more effectively.

Thanks for reading! Feel free to share your thoughts and questions in the comments below.