Скачать или смотреть Troubleshooting: ENV variables not coming through godotenv in Docker

Discover how to effectively handle environment variables in your Go web app using Docker and `godotenv`, and learn best practices for managing your configuration.
---
This video is based on the question https://stackoverflow.com/q/66314534/ asked by the user 'jpazzajpeg' ( https://stackoverflow.com/u/7908215/ ) and on the answer https://stackoverflow.com/a/66317257/ provided by the user 'morganbaz' ( https://stackoverflow.com/u/5328069/ ) 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: ENV variables not coming through godotenv Docker

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: ENV Variables Not Coming Through godotenv in Docker

If you're developing a web app in Go that runs in a Docker container and uses the godotenv package to manage your environment variables, you might run into an issue where the variables aren't being read properly. This can be frustrating, especially when you're getting the error message, "Error getting env, not coming through." In this guide, we will explore the problem and provide a comprehensive guide on how to fix it.

Understanding the Problem

The Go Web Application

You have a web app written in Go that you have dockerized using Docker and Docker Compose. Your configuration includes various files such as main.go, .env, docker-compose.yml, and Dockerfile, all located in the root of your project.

The Error

When you run the command docker-compose up, you receive the following error message:

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

This indicates that the application is unable to read the environment variables defined in your .env file.

Solution Breakdown

1. Using env_file in Docker Compose

If you are already using the env_file option in your docker-compose.yml, it's important to note that you may not need godotenv at all. Docker Compose automatically passes environment variables from .env files to your container, making it unnecessary to load them manually using godotenv.

Example of a minimal Docker Compose setup:

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

In this example, if you have a .env file that looks like this:

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

Running docker-compose up would yield:

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

Benefits of Using env_file

Simplicity: You can pass environment variables without rebuilding your container.

Efficiency: Allows for quick updates to the environment without changing the code.

2. Keeping godotenv in Play

If you prefer to use godotenv, you can resolve the loading issue by ensuring that the .env file is indeed accessible to godotenv during runtime. Uncommenting the line that copies the .env file in your Dockerfile solves this problem.

Dockerfile Modification:

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

By including this line, godotenv will be able to locate the .env file in the same directory.

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

You should now see:

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

3. Keeping in Sync with Filesystem

If you're looking to keep your environment variables in sync with your local filesystem, consider using Docker volumes to link your .env file. This way, changes to the .env on your host system will be reflected inside the container without needing to rebuild.

Conclusion

In conclusion, if you're facing issues with reading environment variables in your Go web application running in Docker, first check if you really need godotenv. Utilize Docker's built-in functionality to manage environment variables effectively through the env_file option. If you do choose to use godotenv, ensure the .env file is properly copied into the container. This way, you can eliminate errors and streamline your development process.

By keeping these practices in mind, you'll become adept at managing your environment variables and avoiding common pitfalls in Docker development. Happy coding!