No support for Docker compatibility mode enablement button for Linux (use documentation only)

[cdrage]

Unfortunately, we wont be able to implement an "automatic" compatibility-mode button for Linux.

This is due to:

• Flatpak's sandbox model for no access to system services
• If we were to enable it manually with --socket=system-bus when building, it's only recommended for dev environments (see: https://docs.flatpak.org/_/downloads/en/latest/pdf/ and where it says: "Access to the entire bus with --socket=system-bus or --socket=session-bus should be avoided, unless the application is a development tool."
• Despite podman desktop being a development tool, opening up the system socket access just for compatibility enablement would be a big security risk.
• Too many libraries / upkeep for implementation in order to implement automatic enablement. Better to "tell" the developer to open a terminal and type in systemctl enable --now podman.socket.

I went ahead and implemented it here: #1847 unfortunately this will only work on non-flatpak environments. I only realized until after that Flatpak permissions are highly sandboxed for systemd / systemctl calls.

When trying to implement it within electron + flatpak, I created the code necessary to communicate to the API here:
https://gist.github.com/cdrage/beb190a32eaf1909bf19c76f93f1f926

Despite API calls, this unfortunately this requires us to add:

finish-args:
  - --socket=system-bus

To the electron-builder YAML which is not recommended by Flatpak for us to do.

This would also require us to add the org.freedesktop.DBus GLib runtime for enablement.

Solution:

Instead we should prompt the user to just type in systemctl enable --now podman.socket and have Podman Desktop detect that the socket has indeed been enabled / etc.

[benoitf]

we're able to call with flatpak some commands using flatpak-spawn. It does not work ?

[cdrage]

@benoitf Not well. I'm going to modify it and find a way to do it without so many libraries / API calls.

[cdrage]

The problem is being able to run it under sudo for flatpak-spawn which is causing most of the issues, I've opened up the PR here if you were curious with regards to my development: #1925

Two issues:

1. Issue with sudo-prompt on on non-flatpak environments:

Which can be fixed by applying jorangreef/sudo-prompt#123

2. Running flatpak-spawn --host sudo systemctl enable --now podman.socket.

See: https://discussion.fedoraproject.org/t/host-spawn-a-better-way-to-run-host-commands-from-inside-your-toolbox/40876/3 and https://github.com/1player/host-spawn

We'd have to implement a way to successfully run sudo / permissions.

I'm going to try a few more things (in Fedora we can have it force prompt to ask for password natively) and test on Ubuntu as well.

[cdrage]

Closing in favour of: #1925

On Fedora / Ubuntu, they will automatically initiate a prompt to enter a password for privileges when using flatpak-spawn, but not on Debian.