Скачать или смотреть Resolving docker-compose Environment Variable Issues in WSL on Ubuntu

Learn how to fix the problem with `docker-compose` not reading environment variables on Ubuntu within WSL on Windows 10. Discover the solution to ensure your Docker projects run smoothly.
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Troubleshooting docker-compose Environment Variable Issues in WSL on Ubuntu

If you're working with Docker on a Windows 10 machine using Windows Subsystem for Linux (WSL) and have encountered issues with docker-compose not reading environment variables, you're not alone. This problem can be particularly frustrating, especially when your setup works flawlessly on Unix-based systems. In this guide, we will explore the common root cause of this issue and provide a step-by-step solution to get your environment variables loaded correctly.

The Problem: Missing Environment Variables

You have a Docker project that relies on specific environment variables to function. Here's what you might encounter:

You have created a .envrc file on your WSL Ubuntu instance, which contains your environment variables.

When you run the command source .envrc, the variables load correctly and can be confirmed with printenv.

Yet, despite this, when you run docker-compose up my_container, the required environment variables do not seem to be passed to Docker. Hardcoding the variables directly into your docker-compose.yml file works without any issues, but that's not a maintainable solution.

Understanding the Root Cause

After some troubleshooting, it was found that the issue originated from the way line endings were handled between Windows and Unix systems. Windows uses different line endings (carriage return and line feed - \r\n) compared to Unix's just line feed (\n). This discrepancy can lead to unexpected behavior in handling files created or edited in different environments.

Key Symptoms

Environment variables seem to load in the terminal but fail to propagate to Docker.

The output of debugging commands like docker-compose config shows inconsistencies.

The Solution: Fixing Line Endings

To resolve this issue and ensure your environment variables are recognized by docker-compose, you need to save your .envrc file with the correct line endings for a Linux environment. Here’s how to do that:

Step 1: Check Line Endings

First, you can check the line endings of your .envrc file. If you're using a compatible text editor, look for a feature that indicates line endings or helps you convert them.

Step 2: Use a Linux-Compatible Text Editor

Open your .envrc file in a text editor that supports Unix-style line endings, such as Visual Studio Code, Sublime Text, or a command-line editor like nano or vim.

Ensure to configure the editor to save files with Unix line endings (LF).

For example, in Visual Studio Code:

Open your .envrc file.

Click on the CRLF button in the bottom-right corner of the window.

Select LF from the dropdown menu.

Save the file.

Step 3: Re-check Environment Variables

After saving your .envrc file with the corrected line endings, run the following commands to verify that your environment variables are loaded properly:

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

Conclusion

By following these remedies, you should be able to resolve the issues with docker-compose not reading your environment variables on Ubuntu inside WSL. The critical takeaway is ensuring that files created or modified in Windows adhere to the Unix line ending conventions, which can prevent a host of compatibility issues.

If you continue to face challenges, ensure your Docker and WSL installations are up-to-date, and refer to community forums for assistance. Happy coding!