Env File for Docker

TODO: collapasable, copyable, download, etc

We are baking ENV variables into our Dockerfile, but that seems dumb. Is there a way to launch a docker container and reference a file that is a bunch of env variables?Yes, baking environment variables directly into a Dockerfile is generally not a good practice, especially for sensitive information like passwords or API keys. Instead, you can use an environment file to pass environment variables to your Docker container at runtime. This method keeps your Docker images more secure and flexible.

Here's how you can do it:

1. Create an Environment File:

   Create a file named .env (or any name you prefer) and list your environment variables in it:

   DATABASE_URL=your_database_url
   API_KEY=your_api_key
   OTHER_ENV_VAR=value
   

2. Run the Docker Container with the Environment File:

   When you run your Docker container, use the --env-file option to reference your environment file:

   docker run --env-file .env your_image_name
   

   This command tells Docker to load the environment variables from the .env file and pass them to the container.

Example

Assuming you have the following .env file:

DATABASE_URL=postgres://user:password@host:port/db
API_KEY=abcd1234

And you want to run a Docker container from an image named my_app_image, you would use:

docker run --env-file .env my_app_image

Additional Tips

• Docker Compose: If you are using Docker Compose, you can specify the environment file in your docker-compose.yml:

  version: '3'
  services:
    app:
      image: my_app_image
      env_file:
        - .env
  

• Security: Ensure that your .env file is not included in your version control system by adding it to your .gitignore.

• Validation: It’s good practice to validate the presence of required environment variables in your application’s entry script.

By following this approach, you can manage your environment variables more securely and flexibly.

Env File for Docker created at Tue Jan 20 1970 20:38:07 GMT+0000 (Coordinated Universal Time)