https://github.com/kevinmichaelchen/docker-compose-env-file-stack

Stack multiple env_files together in Docker Compose
https://github.com/kevinmichaelchen/docker-compose-env-file-stack

Last synced: about 1 month ago
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Stack multiple env_files together in Docker Compose

• Host: GitHub
• URL: https://github.com/kevinmichaelchen/docker-compose-env-file-stack
• Owner: kevinmichaelchen
• Created: 2022-11-08T23:36:48.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2022-11-09T00:25:07.000Z (about 2 years ago)
• Last Synced: 2024-06-20T21:09:19.088Z (6 months ago)
• Language: Go
• Size: 2.93 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
A demonstration of possibly unintuitive behavior.

Here we have a simple Go program that logs its `PORT` env var and spins up a

simple HTTP server on that port.

We also have a Docker Compose file that stacks 2 different `env_file` options,

and does a port-forwarding.

```yaml

    env_file:

      - .env

      - app.env

    ports:

      - "${PORT}:${PORT}"

```

## Expectations

`.env` has a port of 8080, and `app.env` has a port of 9090. Because `app.env`

is stacked on top of `.env`, its 9090 that is ultimately set as the value.

This is as you'd expect.

However, the port forwarding is where things are surprising. It's forwarded as

```

8080:8080

```

This is an informative [StackOverflow post](https://stackoverflow.com/questions/52664673/how-to-get-port-of-docker-compose-from-env-file):

> The env_file option will only set environment variables in the Docker

> container itself. Not on the host which is used during the Compose 'build'.