Quadlets can be debugged with systemd-analyze --generators=true verify example.service (an alternative to podman-system-generator -dryrun)

[eriksjolund]

I have two files my1.container and my2.container. The first one contains a syntax error (the key jImage)

/var/home/test/.config/containers/systemd/my1.container

[Container]
jImage=docker.io/library/alpine
Exec=/bin/sh -c "sleep 300"

/var/home/test/.config/containers/systemd/my2.container

[Container]
Image=docker.io/library/alpine
Exec=/bin/sh -c "sleep 300"

Test 1

1. Run command

   systemd-analyze --user --generators=true verify my1.service
   

   The following output is printed

   quadlet-generator[9752]: converting "my1.container": unsupported key 'jImage' in group 'Container' in 
   /var/home/test/.config/containers/systemd/my1.container
   /usr/lib/systemd/user-generators/podman-user-generator failed with exit status 1.
   Unit my1.service not found.
   

Test 2

1. Run command

   /usr/lib/systemd/system-generators/podman-system-generator --user --dryrun
   

   The following output is printed

   quadlet-generator[9733]: Loading source unit file /var/home/test/.config/containers/systemd/my1.container
   quadlet-generator[9733]: Loading source unit file /var/home/test/.config/containers/systemd/my2.container
   ---my2.service---
   [X-Container]
   Image=docker.io/library/alpine
   Exec=/bin/sh -c "sleep 300"
   
   
   [Unit]
   Wants=podman-user-wait-network-online.service
   After=podman-user-wait-network-online.service
   SourcePath=/var/home/test/.config/containers/systemd/my2.container
   RequiresMountsFor=%t/containers
   
   [Service]
   Environment=PODMAN_SYSTEMD_UNIT=%n
   KillMode=mixed
   ExecStop=/usr/bin/podman rm -v -f -i --cidfile=%t/%N.cid
   ExecStopPost=-/usr/bin/podman rm -v -f -i --cidfile=%t/%N.cid
   Delegate=yes
   Type=notify
   NotifyAccess=all
   SyslogIdentifier=%N
   ExecStart=/usr/bin/podman run --name systemd-%N --cidfile=%t/%N.cid --replace --rm --cgroups=split --sdnotify=conmon -d docker.io/library/alpine /bin/sh -c "sleep 300"
   
   quadlet-generator[9733]: converting "my1.container": unsupported key 'jImage' in group 'Container' in /var/home/test/.config/containers/systemd/my1.container
   

Discussion

The command

systemd-analyze --user --generators=true verify my1.service

seems to be more user-friendly because it just prints the error messages.

It is possible to achieve a similar result by adding > /dev/null

$ /usr/lib/systemd/system-generators/podman-system-generator --user --dryrun > /dev/null
quadlet-generator[9787]: Loading source unit file /var/home/test/.config/containers/systemd/my1.container
quadlet-generator[9787]: Loading source unit file /var/home/test/.config/containers/systemd/my2.container
quadlet-generator[9787]: converting "my1.container": unsupported key 'jImage' in group 'Container' in /var/home/test/.config/containers/systemd/my1.container

(Some additional lines containing Loading source unit file are also listed)

Side note 1: I verified that it is possible to analyse a quadlets in a custom directory path with

QUADLET_UNIT_DIRS=/some/path systemd-analyze --user --generators=true verify my1.service

Side note 2:
The command systemd-analyze verify performs additional checks on
the generated service unit. (See https://www.man7.org/linux/man-pages/man1/systemd-analyze.1.html)