Install directly from .flatpak file

[baduhai]

I'd like to be able to install flatpaks directly from .flatpak files. More specifically, I want to install OrcaSlicer which doesn't have a flatpakref and isn't in any specific remote, the flatpaks are released as github releases.

[gmodena]

Hey @baduhai . This should not be too hard to implement, and can def benefit more people.

I'll have a look at it after #136.

[gmodena]

This should not be too hard to implement

I spoke too quickly. Installing from a file is straightforward, but handling state is not as simple.
tl;dr: this work is in scope, but it won't make it to the next release. I'll prob need to tackle #85 first.

The key observation is that nix-flatpak will need to resolve the file to an application ID to manage its state (e.g., for uninstalls and updates).

Considerations

1 Resolving Application IDs from local files

While it is possible to query a local file's metadata, the file must comply with Flatpak's conventions for application IDs. For example, a file named OrcaSlicer-Linux-flatpak_V2.3.0-dev.flatpak would need to be renamed to something like io.github.softfever.OrcaSlicer.flatpak to make it queryable.

At this point, we might just request users to explicitly provide the application ID in their configuration:

packages = [
  { appId = "io.github.softfever.OrcaSlicer"; path = "OrcaSlicer-Linux-flatpak_V2.3.0-dev.flatpak"; }
];

Either approach feels cumbersome for the end user.

2. Issues with updates

The heuristic to determine if an app needs updating is to check if path has changed since the previous activation. This can get messy if we ask users to rename files (see point 1). We might require adding a sha256 to the config.

We'll also need to explicitly exclude local files installs from the default update path:
once the application is installed, a "mock" origin is generated. However, any lookup attempts will result in an error. This creates problems when running nix-flatpak default update code path.
For example, trying to update the application using the following command would fail:

 $ flatpak install --user --or-update io.github.softfever.OrcaSlicer
 Looking for matches…
 error: No remote refs found for ‘io.github.softfever.OrcaSlicer’

Which make sense, but I was hoping in a no-op.

3. State Persistence

If we need to explicitly identify provenance, changes may be required to how nix-flatpak persists its state. Currently, we only store a list of app IDs for installed packages. AFAIK those alone are not enough to tell if the application was installed from file. So we'll need a richer state file. See #85.

[kagurazaka-ayano]

I don't think the path variable exists...

my config:

flake.nix:

{
  description = "My nix config";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    nur = {
      url = "github:nix-community/NUR";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    home-manager = {
      url = "github:nix-community/home-manager";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    darwin.url = "github:LnL7/nix-darwin/master";
    darwin.inputs.nixpkgs.follows = "nixpkgs";
    nix-flatpak.url = "github:gmodena/nix-flatpak";
    nixgl = {
      url = "github:nix-community/nixGL";
      # require as in issue https://github.com/nix-community/home-manager/issues/6035
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs =
    { self, nixpkgs, home-manager, darwin, nix-flatpak, nixgl, ... }@inputs:
    let inherit (self) outputs;
    in {
...
      homeConfigurations = {
        "ayano" = home-manager.lib.homeManagerConfiguration {
          pkgs = import nixpkgs {
            system = "x86_64-linux";
            config.allowUnfree = true;
            overlays = [
              nixgl.overlay
            ];
          };
          extraSpecialArgs = {
            inherit inputs outputs nixgl;
            flake-inputs = inputs;
          };
          modules =
            [ ./home_desktop.nix ];
        };
      };
    };
}

home-desktop.nix:

...
  imports = [
    ...
    (import ./modules/flatpak {
      flake-inputs = flake-inputs;
      fetchurl = pkgs.fetchurl;
    })
  ];
...

modules/flatpak/default.nix

  imports = [ flake-inputs.nix-flatpak.homeManagerModules.nix-flatpak ];
  services.flatpak = {
    enable = true;
    packages = [{
      appId = "moe.nyarchlinux.assistant";
      path = fetchurl {
        url =
          "https://github.com/NyarchLinux/NyarchAssistant/releases/latest/download/nyarchassistant.flatpak";
        hash = "sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=";
      };
    }];
  };

output: https://pastebin.ubuntu.com/p/wKM9PDCJS8/

[baduhai]

I don't think the path variable exists...

It doesn't, that was just @gmodena brainstorming ways to solve this issue. It is currently impossible to install from a .flatpak file.

[gmodena]

I do have some work in flight on this, that I hope to make available soon-ish. Right now I'm still daily driving it, to iron out some bugs.
Working with bundles was a bit more tricky than I had anticipated.

[gmodena]

I do have some work in flight on this, that I hope to make available soon-ish. Right now I'm still daily driving it, to iron out some bugs. Working with bundles was a bit more tricky than I had anticipated.

@baduhai @kagurazaka-ayano if you want to give it a go, you can try this feature by tracking the main branch.
PR #160 has some examples - and gotchas - on how to install local files (using OrcaSlicer as an example). I might do some f/up work to the API before release.