desktop: AppImage compiling and uploading as artifact in GitHub Actions

[kevin-wijnen]

AppImage support

I am looking to introduce AppImage support to the Ruffle project's desktop app for a standalone version with all necessary shared libraries included. AppImages are similar to Windows' .exe executables, with the possibility of having dependencies built-in to allow it to run on any Linux system regardless of installed shared libraries.

Using AppImages is one of the alternative ways of distributing the emulator to any Linux system. This is a benefit for those running a Linux distro that does not have the capabilities of installing said dependencies because of a locked down filesystem (e.g. Fedora Silverblue and Valve Steam Deck's SteamOS 3). Another way of distribution of said packaged binaries, is through Flatpak. Flatpak support was currently being worked on by someone else through #9220 , but considering it is still work in progress and the complexity of adding Flatpak support, I have tried to look into how to integrate AppImage support instead.

Cargo AppImage seems to be a suitable solution, by adding the following steps to the current CI setup:

• Installing appimagetool and cargo-appimage
• Making appimagetool executable and putting the path magic byte in (following the Dockerfile provided in the project's README)
• Uploading the artifact to GitHub as part of a release.

I am currently working on it in my fork, but figured opening an issue and making a draft pull request to try and attract assistance to make it work. Especially as I am currently inexperienced with Rust to tackle this feature request on my own. See #12402 for my own (not working) attempt.

[kevin-wijnen]

Quick notes:

• Using Cargo AppImage does not work currently, presumably due to a bug (as mentioned in desktop,ci: Adding AppImage support #12402).
• Another possible way is to use appimagetool directly, as demonstrated in this blog post about compiling Rust projects into working AppImages. I am concerned with compatibility however, if there's no attention given to including the necessary shared libraries, which will require further investigation. Especially as someone else has mentioned on a Discourse forum that bundling the necessary libraries is not done automatically. Is there any list of used shared libraries for the Linux desktop standalone program, and its sources/where they are during the CI process to copy them over to include them with the Rust program?

I'll try to see if I can have it packaged through appimagetool directly next week or the week after.

[kevin-wijnen]

Returning to this issue:

• No update has been given about Cargo AppImage's issue - thus the tool currently seems unfit to use for this particular project.
• A new packaging tool for Rust projects has popped up, called Cargo Packager. Needs further investigation/experimentation from my side, but this would also help with Ruffle .deb or appimage file #12633 regarding .deb file distribution.