config: make platforms as a list for users and images

The `images` output attribute is now similar to packages as an attribute
set of packages with their platforms as the first level.

flake.nix

@@ -83,7 +83,7 @@
       users = lib'.importTOML ./users.toml;
 
       # A set of image-related utilities for the flake outputs.
-      inherit (import ./lib/images.nix { inherit inputs; lib = lib'; }) mkHost mkHome mkImage;
+      inherit (import ./lib/images.nix { inherit inputs; lib = lib'; }) mkHost mkHome mkImage listImagesWithSystems;
 
       # The order here is important(?).
       overlays = [
@@ -294,30 +294,35 @@
 
       # A list of NixOS configurations from the `./hosts` folder. It also has
       # some sensible default configurations.
-      nixosConfigurations = lib'.mapAttrs
+      nixosConfigurations =
-        (host: metadata:
+        let
-          let
+          images' = listImagesWithSystems images;
-            path = ./hosts/${host};
+        in
-            extraModules = [
+        lib'.mapAttrs
-              ({ lib, ... }: {
+          (_: host:
-                config = lib.mkMerge [
+            let
-                  { networking.hostName = metadata.hostname or host; }
+              name = host._name;
+              path = ./hosts/${name};
+              extraModules = [
+                ({ lib, ... }: {
+                  config = lib.mkMerge [
+                    { networking.hostName = lib.mkForce name; }
 
-                  (lib.mkIf (metadata ? domain)
+                    (lib.mkIf (host ? domain)
-                    { networking.domain = metadata.domain; })
+                      { networking.domain = lib.mkForce host.domain; })
-                ];
+                  ];
-              })
+                })
 
-              hostSharedConfig
+                hostSharedConfig
-              path
+                path
-            ];
+              ];
-          in
+            in
-          mkHost {
+            mkHost {
-            inherit extraModules extraArgs;
+              inherit extraModules extraArgs;
-            system = metadata.system or defaultSystem;
+              system = host._system;
-            nixpkgs-channel = metadata.nixpkgs-channel or "nixpkgs";
+              nixpkgs-channel = host.nixpkgs-channel or "nixpkgs";
-          })
+            })
-        (lib'.filterAttrs (name: host: (host.format or "iso") == "iso") images);
+          (lib'.filterAttrs (_: host: (host.format or "iso") == "iso") images');
 
       # We're going to make our custom modules available for our flake. Whether
       # or not this is a good thing is debatable, I just want to test it.
@@ -325,10 +330,15 @@
 
       # I can now install home-manager users in non-NixOS systems.
       # NICE!
-      homeConfigurations = lib'.mapAttrs
+      homeConfigurations =
+        let
+          users' = listImagesWithSystems users;
+        in
+        lib'.mapAttrs
         (name: metadata:
           let
-            system = metadata.system or defaultSystem;
+            name = metadata._name;
+            system = metadata._system;
             pkgs = import inputs."${metadata.nixpkgs-channel or "nixpkgs"}" {
               inherit system overlays;
             };
@@ -359,7 +369,7 @@
             inherit pkgs system extraModules extraArgs;
             home-manager-channel = metadata.home-manager-channel or "home-manager";
           })
-        users;
+        users';
 
       # Extending home-manager with my custom modules, if anyone cares.
       homeModules =
@@ -386,30 +396,34 @@
       # somewhere else including those NixOS configurations that are built as
       # an ISO.
       images =
-        lib'.mapAttrs
+        forAllSystems (system:
-          (host: metadata:
+          let
-            let
+            images' = lib'.filterAttrs (host: metadata: lib'.elem system metadata.systems) images;
-              system = metadata.system or defaultSystem;
+          in
-              nixpkgs-channel = metadata.nixpkgs-channel or "nixpkgs";
+          lib'.mapAttrs
-              pkgs = import inputs."${nixpkgs-channel}" { inherit system overlays; };
+            (host: metadata:
-              format = metadata.format or "iso";
+              let
-            in
+                inherit system;
-            mkImage {
+                nixpkgs-channel = metadata.nixpkgs-channel or "nixpkgs";
-              inherit format system pkgs extraArgs;
+                pkgs = import inputs."${nixpkgs-channel}" { inherit system overlays; };
-              extraModules = [
+                format = metadata.format or "iso";
-                ({ lib, ... }: {
+              in
-                  config = lib.mkMerge [
+              mkImage {
-                    { networking.hostName = lib.mkForce metadata.hostname or host; }
+                inherit format system pkgs extraArgs;
+                extraModules = [
+                  ({ lib, ... }: {
+                    config = lib.mkMerge [
+                      { networking.hostName = lib.mkForce metadata.hostname or host; }
 
-                    (lib.mkIf (metadata ? domain)
+                      (lib.mkIf (metadata ? domain)
-                      { networking.domain = lib.mkForce metadata.domain; })
+                        { networking.domain = lib.mkForce metadata.domain; })
-                  ];
+                    ];
-                })
+                  })
-                hostSharedConfig
+                  hostSharedConfig
-                ./hosts/${host}
+                  ./hosts/${host}
-              ];
+                ];
-            })
+              })
-          images;
+            images');
 
       # My several development shells for usual type of projects. This is much
       # more preferable than installing all of the packages at the system

images.toml

@@ -8,13 +8,12 @@
 #
 # Take note, any images with the "iso" format is essentially made to be
 # deployed somewhere (e.g., desktop, homelab server, VPS).
-
 [ni]
-system = "x86_64-linux"
+systems = [ "x86_64-linux" ]
 format = "iso"
 
 [plover]
-system = "x86_64-linux"
+systems = [ "x86_64-linux" ]
 format = "iso"
 domain = "foodogsquared.one"
 
@@ -24,14 +23,20 @@ auto-rollback = true
 magic-rollback = true
 
 [void]
-system = "x86_64-linux"
+systems = [ "x86_64-linux" ]
 format = "vm"
 
 [bootstrap]
-system = "x86_64-linux"
+systems = [
+  "aarch64-linux",
+  "x86_64-linux",
+]
 format = "install-iso"
 nixpkgs-channel = "nixos-unstable-small"
 
 [graphical-installer]
-system = "x86_64-linux"
+systems = [
+  "aarch64-linux",
+  "x86_64-linux",
+]
 format = "install-iso"

lib/images.nix

@@ -42,4 +42,30 @@
         # Our own modules.
         ++ extraModules;
     };
+
+  listImagesWithSystems = data:
+    lib.foldlAttrs
+      (acc: name: metadata:
+      let
+        name' = metadata.hostname or name;
+      in
+        if lib.length metadata.systems > 1 then
+          acc // (lib.foldl
+            (images: system: images // {
+              "${name'}-${system}" = metadata // {
+                _system = system;
+                _name = name';
+              };
+            })
+            {}
+            metadata.systems)
+        else
+          acc // {
+            "${name'}" = metadata // {
+              _system = lib.head metadata.systems;
+              _name = name';
+            };
+          })
+      {}
+      data;
 }

users.toml

@@ -2,7 +2,10 @@
 # of the users defined here should correspond to one of the home-manager users
 # at `./users/home-manager/`.
 [foo-dogsquared]
-system = "x86_64-linux"
+systems = [
+  "aarch64-linux",
+  "x86_64-linux",
+]
 
 [plover]
-system = "x86_64-linux"
+systems = [ "x86_64-linux" ]