Demo of docker-compose issue with --project-directory

This demo relates to changes introduced by docker/compose#6134

The understanding is that --project-directory will allow you run start up a docker-compose from another directory by specifying the 'project directory'. The understanding is that it will also load the .env file within that directory.

This pull request is only included in the latest release so ensure you're using docker-compose from https://github.com/docker/compose/releases/tag/1.23.0-rc3.

Demo 1

• Run docker-compose --project-directory docker up from the root of the project

Expected behaviour

The docker container is started using the .env file.

Actual behaviour

ERROR:
        Can't find a suitable configuration file in this directory or any
        parent. Are you in the right directory?

        Supported filenames: docker-compose.yml, docker-compose.yaml

Demo 2

• Run docker-compose --project-directory docker -f docker/docker-compose.yml up from the root of the project

Expected behaviour

The docker container is started using the .env file.

Actual behaviour

ERROR:
WARNING: The TAG variable is not set. Defaulting to a blank string.
ERROR: no such image: java:: invalid reference format

Working example

• Run docker-compose --project-directory docker config from the root of the project

Result

services:
  java:
    command: java -version
    image: java:alpine
version: '3.1'