jaychou2211 / env_config

Test: How to avoid hardcoding environment variables in docker-compose.yml

env_config

Test: How to avoid hardcoding environment variables in docker-compose.yml

Compose file

Substitute with an .env file

The .env file is useful if you have multiple environment variables you need to store.

Below is a simple example:

$ cat .env
TAG=v1.5

$ cat compose.yml
services:
  web:
    image: "webapp:${TAG}"

When you run docker compose up, the web service defined in the Compose file substitutes in the image webapp:v1.5 which was set in the .env file. You can verify this with the config command, which prints your resolved application config to the terminal:

content_copy
$ docker compose config

services:
  web:
    image: 'webapp:v1.5'