nixos/flake.nix

{
  description = "LAN NixOS configs";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05";
    nixos-conf-editor.url = "github:snowfallorg/nixos-conf-editor";
    home-manager = {
      url = "github:nix-community/home-manager/release-26.05";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    disko = {
      url = "github:nix-community/disko";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    sops-nix = {
      url = "github:Mic92/sops-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, nixos-conf-editor, home-manager, sops-nix, ... } @ inputs:

    let
      system = "x86_64-linux";
      inherit (nixpkgs) lib;
      pkgs = nixpkgs.legacyPackages.${system};
      vars = import ./variables.nix;

      # Generates a nixosConfiguration from a platform (what it runs on) and
      # a build type (what it's for), plus the per-identity host.nix that
      # carries the bits that must stay fixed regardless of platform
      # (hostName, hostId, per-machine secrets). Every build type except
      # nix-cache itself consumes the nix-cache substituter and remote
      # builder.
      mkTarget = { platform, buildType, hostPath, homeFile ? ./modules/common/home.nix }:
        let
          flakeTarget = "${platform}-${buildType}";
        in
        nixpkgs.lib.nixosSystem {
          inherit system;
          modules = [
            inputs.disko.nixosModules.disko
            sops-nix.nixosModules.sops
            ./modules/common/configuration.nix
            ./modules/platforms/${platform}.nix
            ./modules/build-types/${buildType}.nix
            hostPath
            { environment.etc."flake-target".text = flakeTarget; }
            home-manager.nixosModules.home-manager
            {
              home-manager = {
                useGlobalPkgs = true;
                useUserPackages = true;
                extraSpecialArgs = { inherit vars; };
                users.nixos = import homeFile;
              };
            }
          ] ++ lib.optionals (buildType != "nix-cache") [
            ./modules/nix-cache/client.nix
            ./modules/nix-cache/remote-builder-client.nix
          ];
          # flakeTarget is passed via specialArgs (not read back from
          # config.environment.etc."flake-target" above) specifically so
          # modules/platforms/lxc.nix can use it to select its own host key
          # file without a same-option circular dependency (a module
          # contributing to environment.etc can't read the merged
          # environment.etc it's itself contributing to).
          specialArgs = { inherit inputs vars netbootSystem flakeTarget; };
        };

      # Generated platform x build-type matrix. pxe-boot has no linode
      # variant (PXE/DHCP/TFTP need LAN L2 adjacency, which a Linode VPS
      # doesn't have).
      generatedTargets = {
        linode-minimal = mkTarget { platform = "linode"; buildType = "minimal"; hostPath = ./hosts/nix-minimal/host.nix; };
        proxmox-minimal = mkTarget { platform = "proxmox"; buildType = "minimal"; hostPath = ./hosts/nix-minimal/host.nix; };
        lxc-minimal = mkTarget { platform = "lxc"; buildType = "minimal"; hostPath = ./hosts/nix-minimal/host.nix; };

        linode-nix-cache = mkTarget { platform = "linode"; buildType = "nix-cache"; hostPath = ./hosts/nix-cache/host.nix; };
        proxmox-nix-cache = mkTarget { platform = "proxmox"; buildType = "nix-cache"; hostPath = ./hosts/nix-cache/host.nix; };
        lxc-nix-cache = mkTarget { platform = "lxc"; buildType = "nix-cache"; hostPath = ./hosts/nix-cache/host.nix; };

        linode-server = mkTarget { platform = "linode"; buildType = "server"; hostPath = ./hosts/server/host.nix; };
        proxmox-server = mkTarget { platform = "proxmox"; buildType = "server"; hostPath = ./hosts/server/host.nix; };
        lxc-server = mkTarget { platform = "lxc"; buildType = "server"; hostPath = ./hosts/server/host.nix; };

        linode-docker = mkTarget { platform = "linode"; buildType = "docker"; hostPath = ./hosts/docker/host.nix; };
        proxmox-docker = mkTarget { platform = "proxmox"; buildType = "docker"; hostPath = ./hosts/docker/host.nix; };
        lxc-docker = mkTarget { platform = "lxc"; buildType = "docker"; hostPath = ./hosts/docker/host.nix; };

        linode-gui = mkTarget { platform = "linode"; buildType = "gui"; hostPath = ./hosts/nixos/host.nix; homeFile = ./hosts/nixos/home.nix; };
        proxmox-gui = mkTarget { platform = "proxmox"; buildType = "gui"; hostPath = ./hosts/nixos/host.nix; homeFile = ./hosts/nixos/home.nix; };
        lxc-gui = mkTarget { platform = "lxc"; buildType = "gui"; hostPath = ./hosts/nixos/host.nix; homeFile = ./hosts/nixos/home.nix; };

        proxmox-pxe-boot = mkTarget { platform = "proxmox"; buildType = "pxe-boot"; hostPath = ./hosts/pxe-boot/host.nix; };
        lxc-pxe-boot = mkTarget { platform = "lxc"; buildType = "pxe-boot"; hostPath = ./hosts/pxe-boot/host.nix; };

        linode-tailscale-exit-node = mkTarget { platform = "linode"; buildType = "tailscale-exit-node"; hostPath = ./hosts/tailscale-exit-node/host.nix; };
        proxmox-tailscale-exit-node = mkTarget { platform = "proxmox"; buildType = "tailscale-exit-node"; hostPath = ./hosts/tailscale-exit-node/host.nix; };
        lxc-tailscale-exit-node = mkTarget { platform = "lxc"; buildType = "tailscale-exit-node"; hostPath = ./hosts/tailscale-exit-node/host.nix; };
      };

      # Auto-install environments (migrated from the former nix-auto-installer
      # flake): a self-contained NixOS installer that boots, discovers this
      # flake's own nixosConfigurations over the network, and runs
      # nixos-install against whichever one the operator picks. These are
      # deliberately not part of the platform x build-type matrix above —
      # they're throwaway boot media, not persistent hosts, so they skip
      # disko/sops-nix/home-manager and just need `vars`.
      installerTargets = {
        installer = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = [ ./modules/installer/iso.nix ];
          specialArgs = { inherit vars; };
        };
      };

      # Same installer environment, built as netboot (kernel + initrd +
      # iPXE script) instead of an ISO — this is what packages.pxe bundles.
      netbootSystem = nixpkgs.lib.nixosSystem {
        inherit system;
        modules = [
          ./modules/installer/iso.nix
          ({ modulesPath, ... }: {
            imports = [
              (modulesPath + "/installer/netboot/netboot-minimal.nix")
            ];
          })
        ];
        specialArgs = { inherit vars; };
      };

    in
    {

      nixosConfigurations = generatedTargets // installerTargets;

      # Buildable auto-installer artifacts (`nix build .#<name>`). No `lxc`
      # variant (installer-boots-as-an-LXC-container) or `all` bundle
      # anymore — lxc-* and proxmox-* hosts deploy via their own tarball/
      # disk-image outputs instead (see docs/auto-installer.md and
      # docs/proxmox-images.md), which left the installer's own LXC form
      # with no real use case: it's excluded from the install menu (same
      # bind-mount problem as any LXC nixos-install target) and nothing
      # else needed booting the installer itself as a container.
      packages.${system} = {
        iso = installerTargets.installer.config.system.build.isoImage;

        pxe = pkgs.linkFarm "pxe" [
          { name = "netboot.ipxe"; path = netbootSystem.config.system.build.netbootIpxeScript; }
          { name = "initrd"; path = netbootSystem.config.system.build.netbootRamdisk; }
          { name = "kernel"; path = netbootSystem.config.system.build.kernel; }
        ];
      };
    };
}