How can I configure the project directory on the _remote_ with docker-compose --context/--host?

Docker Engine Compose
1

Hi,

I’ve just discovered --host and --context and it’s wonderful. But there’s one option I’m missing; maybe it’s there and I just can’t find it; maybe I’m doing it wrong; otherwise it’s a feature request =).

How do I make docker-compose --host run within a different project dir on the remote?

The setup

So to illustrate the problem I’ve created minimal project directory for this example-app:

example-app
├── config
│   └── config.txt
├── docker-compose.yaml
└── Dockerfile

The files have the following content:

1: config.txt:

   It works!

2: docker-compose.yaml:

   version: '2.4'

   services:
     app:
       build:
         context: .
       volumes:
         - "./config:/config"

3: Dockerfile:

   FROM busybox:latest
   ENTRYPOINT ["cat", "/config/config.txt"]

When I run this locally the ./config directory will be prefixed by my current directory and evaluate as let’s say /home/me/projects/docker/example-app/config:

docker-compose up --build

This is all fine – “It works!”

Going remote

I now want to deploy this to my remote server, aptly called server in this example.
I’ll state the port number 22 explicitly.

First I copy the config dir to the server in an exampleapp-remote dir:

rsync -e "ssh -p 22" -Rav config user@server:exampleapp-remote/

The server now has this structure:

:
home
├── user
:    └── exampleapp-remote
         └── config
             └── config.txt

Now I run docker-compose locally, issuing it to deploy and invoke the app on the server using --host:

docker-compose --host ssh://user@server:22 up --build

And it fails:

app_1  | cat: can't open '/config/config.txt': No such file or directory

Adding --project-directory exampleapp-remote or --project-directory /home/user/exampleapp-remote doesn’t work, as it accounts for the local directory (I guess).

Moving the config dir to the /home/user/config doesn’t work either because the current dir prefix gets evaluated on the host running docker-compose.

What to do?

A --remote-project-directory would be handy here.

Or maybe something like --host ssh://user@server:22/~/exampleapp-remote or --host ssh://user@server:22/home/user/exampleapp-remote.

Or if a --context was used, perhaps a remote-work-dir could be added to the meta.json file.

How do I solve this? How do I make docker-compose --host run within a different project dir on the remote? Is it even doable?