[FEATURE REQUEST] - Support Steam in a Flatpak

[JoshuaFern]

What problem does the feature request solve?
Sometimes Linux gamers don't install Steam natively but instead opt for the Flatpak version of Steam.

Example mock-up (optional)
The path for Flatpak'd Steam would look something like ~/.var/app/com.valvesoftware.Steam/.steam/steam/steamapps/common/Valheim. It could be implemented as another selectable option, i.e. Xbox, Steam, Steam (Flatpak)

Additional information (optional)
A workaround before this is implemented could be simply linking the Steam native directory to the Steam Flatpak directory. But that doesn't work for me because I have both a native and a Flatpak version of Steam installed.

Another workaround might be trying to run r2modman within the Steam Flatpak. I believe AppImages are not supported within a Flatpak so it must first be extracted then ran. You can enter the Flatpak environment shell by using the command flatpak run --command=/bin/bash com.valvesoftware.Steam and r2modman needs to be ran with the option --no-sandbox. Once you have your mods installed a normal launch won't work, launch Flatpak Steam with options like:
com.valvesoftware.Steam -applaunch 892970 --doorstop-enable true --doorstop-target ~/.var/app/com.valvesoftware.Steam/.config/r2modmanPlus-local/Valheim/profiles/Default/BepInEx/core/BepInEx.Preloader.dll --r2profile Default --doorstop-dll-search-override ~/.var/app/com.valvesoftware.Steam/.config/r2modmanPlus-local/Valheim/profiles/Default/unstripped_corlib

Note, this is not a duplicate of #729 because this issue is relating to using r2modman as an AppImage with Flatpak'd Steam, whereas #729 is relating to distributing r2modman as a Flatpak, potentially useful on the Steam Deck.

[rehashedsalt]

This is required for compatibility with immutable OSes such as Fedora Silverblue/Kinoite

[TheJanzap]

I'm running Flatpak Steam and installed r2modman via AUR and r2modman detected my Steam directory as ~/.var/app/com.valvesoftware.Steam/.local/share/Steam and the game dir was also detected properly. However, upon launching the game, I get the error You are missing the following 32-bit libraries, and Steam may not run: libc.so.6, so it is probably not running Steam correctly?

[mscharley]

I managed to cobble together something that works from answers in a few places:

1. Use flatseal to grant Steam access to xdg-config/r2modmanPlus-local under "Other files".
2. Use the AppImage for r2modman normally to install and manage mods and profiles.
3. Use the help tab inside r2modman while on a profile and copy the launch parameters at the bottom of the page under "Launching the game from outside the mod manager" to get Steam to launch the mod profile.

The "Start modded" and "Start vanilla" buttons in r2modman don't appear to be working as they seem to be trying to run steam outside the flatpak sandbox, but this appears to be the only concession till there's proper support implemented. All the game and data folders all got autodetected correctly for me even though I have my games installed inside the flatpak data folder (ie, in ~/.var/app/com.valvesoftware.Steam)

[bruglet]

I managed to cobble together something that works from answers in a few places:

1. Use flatseal to grant Steam access to `xdg-config/r2modmanPlus-local` under "Other files".

2. Use the AppImage for r2modman normally to install and manage mods and profiles.

3. Use the help tab inside r2modman while on a profile and copy the launch parameters at the bottom of the page under "Launching the game from outside the mod manager" to get Steam to launch the mod profile.

The "Start modded" and "Start vanilla" buttons in r2modman don't appear to be working as they seem to be trying to run steam outside the flatpak sandbox, but this appears to be the only concession till there's proper support implemented. All the game and data folders all got autodetected correctly for me even though I have my games installed inside the flatpak data folder (ie, in ~/.var/app/com.valvesoftware.Steam)

I don't know what happened, r2modman worked just fine with Flatpak Steam just a few weeks ago, but now it has the issues finding libc.so.6. Thank you so much for dropping the solution, I tried everything else to get it working, even deleting my steam library. I'm literally in shambles right now for not remembering to give permissions with flatseal

Perhaps they should add your solution to the documentation or something until a proper solution has been implemented?

[Soapsuds]

Just ran into this today. Would be great if the workaround listed here was added onto this page: https://r2modman.com/troubleshooting/ under game doesn't start at all. Something like:
R2ModMan does not support Flatpak Steam and can not start games. See these instructions to launch modded games from the launch options
And maybe even a warning in the UI if steam is found under .var.

Installing mods worked great though! And thanks for the workaround too!

[ebkr]

That website is not associated with this manager at all

[peacememories]

This is because r2modman uses ${steamDir}/steam.sh regardless of the steam directory it finds:

r2modmanPlus/src/r2mm/launching/runners/linux/SteamGameRunner_Linux.ts

Line 72 in b4825f0

const cmd = `"${steamDir}/steam.sh" -applaunch ${game.activePlatform.storeIdentifier} ${args} ${settings.getContext().gameSpecific.launchParameters}`;

I managed to get this working with the following patch:

diff --git a/src/r2mm/launching/runners/linux/SteamGameRunner_Linux.ts b/src/r2mm/launching/runners/linux/SteamGameRunner_Linux.ts
index ddee0e9..ce396c8 100644
--- a/src/r2mm/launching/runners/linux/SteamGameRunner_Linux.ts
+++ b/src/r2mm/launching/runners/linux/SteamGameRunner_Linux.ts
@@ -69,7 +69,7 @@ export default class SteamGameRunner_Linux extends GameRunnerProvider {
         LoggerProvider.instance.Log(LogSeverity.INFO, `Steam directory is: ${steamDir}`);
 
         try {
-            const cmd = `"${steamDir}/steam.sh" -applaunch ${game.activePlatform.storeIdentifier} ${args} ${settings.getContext().gameSpecific.launchParameters}`;
+            const cmd = `flatpak run com.valvesoftware.Steam -applaunch ${game.activePlatform.storeIdentifier} ${args} ${settings.getContext().gameSpecific.launchParameters}`;
             LoggerProvider.instance.Log(LogSeverity.INFO, `Running command: ${cmd}`);
             await exec(cmd);
         } catch(err) {

Similarly to how nixos adds a patch: https://github.com/NixOS/nixpkgs/blob/nixos-24.05/pkgs/games/r2modman/steam-launch-fix.patch

This is obviously not a proper fix. Ideally one would change the way the command is called depending on the steam directory found, and maybe allow overriding this with an option.

[gegoxaren]

The way it works now is just not viable at all, as the app does not actually install the mods into the game folder.

I expected this to work like r2mod-cli worked, but it did not.

If this is suppose to work at all there needs to be logic to detect if the games is installed as a flatpak and if so, launch the game via flatpak. Alternatively provide a way to toggle or change how steam is launched.

[gegoxaren]

Another thing to note is that Flatpak steam can't actually see the $HOME folder. So when when a flatpak install is detected, it should use $HOME/.var/app/com.valvesoftware.Steam/.config/r2modmanPlus-local as the base dir instead of the standard $HOME/.config/r2modmanPlus-local.

You can migrate over to that using:

cp -r $HOME/.config/r2modmanPlus-local $HOME/.var/app/com.valvesoftware.Steam/.config/r2modmanPlus-local

You can not symlink the directories.

[gegoxaren]

Why has the MR not been merged yet?

[LostWarriorr]

I guess this is more appropriate here because I didn't realize #729 was requesting r2modman to be a flatpak and not just the appimage supporting the flatpak.

Anyways,
For those who can't wait for the merge request (which for whatever reason hasn't been merged yet) I found a way to seamlessly integrate the Appimage into the steam flatpak container without having to launch it through steam. I even went ahead and made a one-liner that will automatically set everything up.

AppImage will update itself as usual.

I ran it and tested it a few times so (hopefully) there are no issues with it:

curl -s https://api.github.com/repos/ebkr/r2modmanPlus/releases/latest | sed 's/[()",{}]/ /g; s/ /\n/g' | grep "https.*releases/download.*AppImage" | wget -qi - && mv --no-copy ~/r2modman*.AppImage ~/.var/app/com.valvesoftware.Steam/.local/share/r2modman.AppImage && wget -qO ~/.icons/r2modman.png https://raw.githubusercontent.com/ebkr/r2modmanPlus/refs/heads/develop/public/icon.png && mkdir -p ~/.var/app/com.valvesoftware.Steam/.local/bin | printf '#!/bin/sh\n~/.local/share/r2modman.AppImage --appimage-extract-and-run --no-sandbox' > ~/.var/app/com.valvesoftware.Steam/.local/bin/r2modman && chmod +x ~/.var/app/com.valvesoftware.Steam/.local/bin/r2modman && chmod +x ~/.var/app/com.valvesoftware.Steam/.local/share/r2modman.AppImage && printf "[Desktop Entry]\nName=r2modman (In Steam Flatpak)\nExec=sh -c \"/usr/bin/flatpak run --command=\"$HOME/.var/app/com.valvesoftware.Steam/.local/bin/r2modman\" com.valvesoftware.Steam & /usr/bin/flatpak run --branch=stable --arch=x86_64 --command=/app/bin/steam --file-forwarding com.valvesoftware.Steam @@u %%U @@ & exit\"\nTerminal=false\nType=Application\nIcon=$HOME/.var/app/com.valvesoftware.Steam/.local/share/squashfs-root/r2modman.png\nStartupWMClass=r2modman\nComment=A simple and easy to use mod manager for several games using Thunderstore.\nMimeType=x-scheme-handler/ror2mm;\nCategories=Game;" > ~/.local/share/applications/r2modmanflatpak.desktop && update-desktop-database ~/.local/share/applications/

If you already have r2modman setup you will need to copy your .configs from your home/.configs folder to the steam flatpak .config at com.valvesoftware.Steam/.config/

you shouldn't need to grant any extra permissions either.

EDIT:

Here is a version that adds the appimage as an extracted app and automatically checks and installs updates if available. Using the above version will work just fine but it does eat up some writes every time it is run, and is slower to start because it has to extract the appimage every time.

cd ~/.var/app/com.valvesoftware.Steam/.local/share && mkdir -p ../bin && curl -s https://api.github.com/repos/ebkr/r2modmanPlus/releases/latest | sed 's/[()",{}]/ /g; s/ /\n/g' | grep "https.*releases/download.*AppImage" | wget -qi - && chmod +x ./r2modman*.AppImage && ./r2modman*.AppImage --appimage-extract && rm ./r2modman*.AppImage && printf "[Desktop Entry]\nName=r2modman (In Steam Flatpak)\nExec=sh -c \"$HOME/.var/app/com.valvesoftware.Steam/.local/bin/launcher & /usr/bin/flatpak run --branch=stable --arch=x86_64 --command=/app/bin/steam --file-forwarding com.valvesoftware.Steam @@u %%U @@ & exit\"\nTerminal=false\nType=Application\nIcon=$HOME/.var/app/com.valvesoftware.Steam/.local/share/squashfs-root/r2modman.png\nStartupWMClass=r2modman\nComment=A simple and easy to use mod manager for several games using Thunderstore.\nMimeType=x-scheme-handler/ror2mm;\nCategories=Game;" > ~/.local/share/applications/r2modmanflatpak.desktop && update-desktop-database ~/.local/share/applications/ && printf '#!/bin/sh\n~/.local/share/squashfs-root/r2modman --no-sandbox' > ../bin/r2modman && chmod +x ../bin/r2modman && printf '#!/bin/sh\n\nif test "$(curl -s https://api.github.com/repos/ebkr/r2modmanPlus/releases/latest | jq -r '\''.tag_name'\'' | cut -c 2-)" = "$(sed '\''8q;d'\'' ~/.var/app/com.valvesoftware.Steam/.local/share/squashfs-root/r2modman.desktop | cut -c 20-)" || test "$(curl -s https://api.github.com/repos/ebkr/r2modmanPlus/releases/latest | jq -r '\''.tag_name'\'' | cut -c 2-)" = ""; then\n\tsh "$(/usr/bin/flatpak run --command='$HOME'/.var/app/com.valvesoftware.Steam/.local/bin/r2modman com.valvesoftware.Steam)"\nelse\n\tcd ~/.var/app/com.valvesoftware.Steam/.local/share && curl -s https://api.github.com/repos/ebkr/r2modmanPlus/releases/latest | sed '\''s/[()",{}]/ /g; s/ /\\n/g'\'' | grep "https.*releases/download.*AppImage" | wget -qi - && chmod +x ./r2modman*.AppImage && ./r2modman*.AppImage --appimage-extract && rm ./r2modman*.AppImage && sh "$(/usr/bin/flatpak run --command='$HOME'/.var/app/com.valvesoftware.Steam/.local/bin/r2modman com.valvesoftware.Steam)";\nfi' > ../bin/launcher && chmod +x ../bin/launcher

I shouldn't have to say this but this method of running r2modman is not officially supported by ebkr.

This way of running appimages inside a flatpak container is probably not officially supported by the flatpak team either.

[gegoxaren]

There are two PRs:
#1462

#798

It should be able to be fixed easely for the devs, but alas...

[ebkr]

It's just a couple of layers:

I'm not hugely opposed to merging one of those PRs beforehand, but I do need to find the time to test it. It's just low priority and involves a fair amount of time. There are some explanations below though:

• I primarily develop on Windows and I'd need to switch my Linux Steam setup to use Flatpak in order to test it. It takes time and breaks my existing Linux development environment
• It's a weird state where yes, supporting launching Flatpak would be nice, but I don't think it's great if we can't also bundle the application as a Flatpak too. I've been doing work towards this, but I'm in a state where it can launch Steam from inside a Flatpak sandbox, but Steam then fails to launch the game.
  • It shows as missing licence if you try to launch a game you don't own
  • Nothing happens if you do own the game
• I did kind of forget about this for a long time

The primary blocker to me is the second point where we aren't also bundling the app itself as Flatpak. It'll lead to people thinking there's a flatpak build, when it reality no, it just supports Flatpak Steam. The reason this is an important factor is because people would generally prefer to install a Flatpak version of the manager when using Steam Deck, and a mention of Flatpak is likely to be half-read and misconstrued.

It's not a solid answer as to why it hasn't been merged, and I'm sure there's ways around it, but that's my thought.