Скачать или смотреть Solving the Permission Denied Issue in GitLab CI with Python's subprocess Module

Discover how to resolve the `PermissionError` in GitLab CI when using Python's subprocess.Popen for file execution.
---
This video is based on the question https://stackoverflow.com/q/75906827/ asked by the user 'Bob' ( https://stackoverflow.com/u/4859268/ ) and on the answer https://stackoverflow.com/a/75907267/ provided by the user 'RAI' ( https://stackoverflow.com/u/21367341/ ) 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: GitLab CI python subprocess.Popen permission denied

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.
---
Solving the Permission Denied Issue in GitLab CI with Python's subprocess Module

When it comes to working with Continuous Integration (CI), nothing can be more frustrating than facing permission errors in your automated jobs. If you’re a developer using GitLab CI and encountering a PermissionError while trying to execute a binary file via Python's subprocess.Popen, you’re not alone. This common issue can stem from a variety of causes and is especially puzzling when you are certain that permissions seem to be set correctly.

The Problem: Understanding PermissionError

Imagine you are running a job in GitLab CI that executes a Python script to start another process. The code looks something like this:

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

However, instead of smoothly running your command, you receive the following error:

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

What’s Going Wrong?

At first glance, it might seem like a straightforward permissions issue, something like forgetting to make the binary file executable. Yet, you check the permissions with the following commands:

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

Surprisingly, everything appears to be in order. You’re executing commands as the root user, and the binary file has the necessary executable permissions. So, where is the problem originating from?

The Solution: Checking File Paths

Based on the initial diagnosis, the permissions are not the cause of the issue. Instead, a more common problem arises from incorrect paths. When you are executing a script within CI, relative paths can create unexpected behavior due to the working directory context. Here’s how to effectively address the issue:

Steps to Diagnose and Fix

Verify the Current Working Directory: Use the os.getcwd() function in Python to check what the current working directory is when the script runs. This will help you understand what the relative path is based on.

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

Adjust Paths as Necessary: Make sure that the path you are using to execute your binary file aligns with the directory from which your Python script is being executed. If the current working directory differs from where your binary file resides, you will need to adjust your path accordingly.

Use Absolute Paths: If the relative paths continue to lead to permission errors, consider converting to absolute paths in your Popen call. This eliminates confusion and ensures that the correct file is always referenced.

Example:

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

Test in Local Environment: Sometimes it helps to replicate the CI environment locally. By running your script in a similar context (same user, same directory structure), you might discover the root cause of the discrepancy more easily.

Conclusion

Facing a PermissionError in GitLab CI can be frustrating, but understanding the root cause is key to resolving the issue. By systematically checking your file paths and ensuring that they are correctly aligned with your current working directory, you can troubleshoot and fix these kinds of problems efficiently.

Remember: Always verify file paths when dealing with subprocesses in CI/CD pipelines! This simple practice can save you time and effort, letting you focus on what you do best—writing great code.