Скачать или смотреть Resolving FileNotFoundError When Using Subprocess in Python

Learn how to troubleshoot the `FileNotFoundError` caused when running subprocess commands in Python scripts. Discover the importance of using the full path for executables.
---
This video is based on the question https://stackoverflow.com/q/63815059/ asked by the user 'Mehdi Khlifi' ( https://stackoverflow.com/u/11481105/ ) and on the answer https://stackoverflow.com/a/63815449/ provided by the user 'JacobIRR' ( https://stackoverflow.com/u/4225229/ ) 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: Running command with subprocess raises FileNotFoundError

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.
---
Troubleshooting FileNotFoundError with Subprocess in Python

Running subprocess commands in Python can sometimes be a struggle, especially when you encounter errors that halt your progress. One such common issue is the dreaded FileNotFoundError. If you've seen an error message like this while trying to execute a command using Python's subprocess module, you're not alone. In this guide, we'll dissect the cause of this problem and provide a clear solution to prevent it from happening again.

The Problem at Hand

A user faced an issue when trying to execute the command trivy -q image -f json alpine:3.10 within a Python script:

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

When running this script, they encountered the following error:

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

Interestingly, this command worked perfectly when used in an interactive Python interpreter. So, what was the discrepancy causing the error in the script?

Understanding the Error

The root of the FileNotFoundError lies in how the Python interpreter locates executable files. When a command is executed in a script, Python needs to find the executable file associated with that command. If Python cannot find trivy, it raises this error.

In contrast, running commands interactively may work simply because the interactive shell may have better access to your PATH environment, or it is configured differently from your script.

The Solution: Provide the Full Path

To resolve this issue, you need to provide the full path to the executable in your command. Here's how to do that:

Find the Full Path of the Executable:

Open a terminal and run the command:

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

This command will return the full path to the trivy executable.

Update Your Python Script:

Replace trivy in your script with its full path that you obtained from the previous step. Suppose the output of which trivy was /usr/local/bin/trivy, you would update your code as follows:

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

Run the Updated Script:

Execute your updated script again, and you should no longer encounter the FileNotFoundError.

Conclusion

The key takeaway here is to remember that when executing external commands in Python using the subprocess module, always ensure that you're providing the full path to the executable. This simple approach will help you avoid the frustrations of FileNotFoundError, and streamline your Python scripting.

Now, go ahead and try this method in your scripts! If you have any more questions or face any other issues, feel free to ask.