https://github.com/rija/compose-variables

Playground project to learn about docker-compose environment variables
https://github.com/rija/compose-variables

Last synced: about 1 month ago
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Playground project to learn about docker-compose environment variables

• Host: GitHub
• URL: https://github.com/rija/compose-variables
• Owner: rija
• Created: 2018-08-03T21:22:40.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-08-03T21:23:00.000Z (over 6 years ago)
• Last Synced: 2024-11-02T15:42:27.362Z (3 months ago)
• Language: Shell
• Size: 1.95 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Demystifying Docker compose variables

I've concocted this project to alleviate the confusion that surround the use of environment variables with docker-compose files.

It's my attempt at clarifying things following the confusion in my head from those Docker issues:

* WARNING: The X variable is not set. Defaulting to a blank string. [#4189](https://github.com/docker/compose/issues/4189)

* Add support for `extends` feature in Compose v3 / docker stack deploy[#31101](https://github.com/moby/moby/issues/31101#issuecomment-301212524)

## Usage

```

$ docker-compose up test

$ docker-compose up prod

$ docker-compose up magic

$ FROM_CLI=wow docker-compose up magic

$ docker-compose up black-magic

$ docker-compose -f docker-compose.yml -f docker-compose.staging.yml up test

$ docker-compose -f docker-compose.yml -f docker-compose.staging.yml up prod

$ docker-compose -f docker-compose.yml -f docker-compose.staging.yml up magic

$ FROM_CLI=wow docker-compose -f docker-compose.yml -f docker-compose.staging.yml up magic

$ docker-compose -f docker-compose.yml -f docker-compose.staging.yml up black-magic

```

you can also run ``docker-compose config`` to display the compose-file with the in-container variables (specfied with **environment:** and **env_file:**) resolved.

you can also set the COMPOSE_FILE environment variable if you don't want to type all the compose file names:

```

$ export COMPOSE_FILE=docker-compose.yml:docker-compose.staging.yml

$ docker-compose up black-magic

```

to test the environment variables "inheritance" feature (to alleviate the disappearance of **extends**): 

```

$ docker-compose up queen-bee worker-bee sentinel-bee

```

## Requirement

it uses docker-compose format version 3.7 which requires Docker Engine 18.06.0+

Feel free to change the "version:" property in the **docker-compose.yml** to support older version or to explore behaviour with previous versions.