Special paths defined as env variables in system files should be mapped as systemd specifiers

[rugk]

Example

E.g. say you have the following YAML:

version: "2.1"
services:
  grocy:
    image: lscr.io/linuxserver/grocy:latest
    container_name: grocy
    volumes:
      - $HOME/config:/config:Z
    ports:
      - 9283:80

This currently get's mapped as (Volume matters here):

[Container]
ContainerName=grocy
Image=lscr.io/linuxserver/grocy:latest
PublishPort=9283:80
Volume=$HOME/config:/config:Z

[Service]
Restart=always

[Install]
WantedBy=default.target

Problem

This does not work, as I dunno… some systemd thing…(?) I guess $HOME is not defined in that context.

in any case the error is something like if you want to start this Quadlet with podman:

(podman)[82122]: grocy.service: Invalid environment variable name evaluates to an empty string: HOME/config:/config:Z

Solution

It should replace some well-known env variables with their systemd equivalents. HOME should be replaced with %h e.g.

Aka the result should be this:

Volume=%h/grocy-data:/config:Z

There are more such variables: https://www.freedesktop.org/software/systemd/man/latest/systemd.unit.html#Specifiers