delft: allow deployment through colemena (#400)

Provide an output that translates nixosConfigurations to a colmena-
compatible output.

Colmena provides a convenient wrapper around building and deploying
machines, than the bare nixos-rebuild we had been using up until now.

Author: mweinelt

delft/flake.lock

@@ -4,6 +4,9 @@
   inputs.agenix.url = "github:ryantm/agenix";
   inputs.agenix.inputs.nixpkgs.follows = "nixpkgs";
 
+  inputs.colmena.url = "github:zhaofengli/colmena";
+  inputs.colmena.inputs.nixpkgs.follows = "nixpkgs";
+
   inputs.disko.url = "github:nix-community/disko";
   inputs.disko.inputs.nixpkgs.follows = "nixpkgs";
 
@@ -20,7 +23,7 @@
   inputs.rfc39.url = "github:NixOS/rfc39";
   inputs.rfc39.inputs.nixpkgs.follows = "nixpkgs";
 
-  outputs = flakes @ { self, agenix, disko, hydra, hydra-scale-equinix-metal, nix, nixpkgs, nixos-channel-scripts, nix-netboot-serve, rfc39 }:
+  outputs = flakes @ { self, agenix, colmena, disko, hydra, hydra-scale-equinix-metal, nix, nixpkgs, nixos-channel-scripts, nix-netboot-serve, rfc39 }:
     let
       inherit (nixpkgs) lib;
 
@@ -67,12 +70,29 @@
         ];
       };
 
+      colmena = {
+        meta = {
+          description = "NixOS.org infrastructure";
+          nixpkgs = import nixpkgs {
+            system = "x86_64-linux";
+          };
+        };
+      } // builtins.mapAttrs
+        (name: value: {
+          nixpkgs.system = value.config.nixpkgs.system;
+          imports = value._module.args.modules;
+          deployment = {
+            targetHost = "${name}.nixos.org";
+          };
+        }) (self.nixosConfigurations);
+
       # TODO: flake-utils.lib.eachDefaultSystem
       devShell.x86_64-linux = let
         pkgs = import nixpkgs { system = "x86_64-linux"; };
       in pkgs.mkShell {
         buildInputs = with pkgs; [
           agenix.packages.x86_64-linux.agenix
+          colmena.packages.x86_64-linux.colmena
         ];
       };
     };