systemd file for docker compose, with added dereference of symlinks

[email protected]

[Unit]
Description=%i service with docker compose
Requires=docker.service
After=docker.service network-online.target autofs.service

[Service]
Type=oneshot
RemainAfterExit=true
WorkingDirectory=/etc/docker/compose/%i
ExecStart=/bin/sh -c 'cd "$(dirname $(realpath /etc/docker/compose/%i/compose.yml))" && docker compose up -d --remove-orphans'
ExecStop=/bin/sh -c 'cd "$(dirname $(realpath /etc/docker/compose/%i/compose.yml))" && docker compose down'

[Install]
WantedBy=multi-user.target

The idea here is that you have a dir called /etc/docker/compose/«project» for each compose project. That's what the typical [email protected] file does.

However, it borks if the compose file in there is a symlink; this is useful if you want the actual compose project somewhere else on the server. You can symlink the whole project file as /etc/docker/compose/«project», but that's still not that tidy, and Compose still thinks it's running in /etc which may break relative paths.

Instead, symlink the compose file as /etc/docker/compose/«project»/compose.yml (apparently the primary name for that file) and this version of the service file will resolve the symlink first and chdir.

Save this file to /etc/systemd/system/[email protected] and something like:

systemctl daemon-reload

mkdir /etc/docker/compose/traefik
ln -s /projects/traefik/compose.yml /etc/docker/compose/traefik/compose.yml

systemctl enable docker-compose@traefik
systemctl start docker-compose@traefik

It might not handle paths with spaces and weird chars, so keep it simple. Improvements welcome.