Switch to flake-based build on nix-builder for nightly rust.

nix/configuration/roles/hydra/default.nix

@@ -2,56 +2,10 @@
   config,
   lib,
   pkgs,
+  nix_builder,
   ...
 }:
 
-let
-  # patchScriptBin =
-  #   {
-  #     filename,
-  #     contents,
-  #     path ? [ ],
-  #   }:
-  #   ((pkgs.writeScriptBin filename contents).overrideAttrs (old: {
-  #     buildInputs = [ pkgs.makeWrapper ];
-  #     buildCommand = "${old.buildCommand}\n patchShebangs $out\nwrapProgram $out/bin/${filename} --prefix PATH : ${lib.makeBinPath path}";
-  #   }));
-  nix_builder = pkgs.rustPlatform.buildRustPackage rec {
-    pname = "nix_builder";
-    version = "0.0.0";
-
-    src = pkgs.fetchgit {
-      url = "https://code.fizz.buzz/talexander/nix_builder.git";
-      # tag = version;
-      rev = "606832f505a1ccc9702cd12c236c3188f9282e82";
-      hash = "sha256-WHvnkCIPDBw0BnrQMnBpmwmYuhlxR4FfkoNWw2DY6XE=";
-      leaveDotGit = false;
-    };
-
-    cargoLock = {
-      lockFile = "${src}/Cargo.lock";
-    };
-
-    meta = with lib; {
-      description = "A builder of nix configs for a build server.";
-      homepage = "https://code.fizz.buzz/talexander/nix_builder";
-      license = licenses.bsd0;
-      maintainers = [ ];
-    };
-
-    nativeBuildInputs = [ pkgs.makeWrapper ];
-
-    postInstall = ''
-      wrapProgram $out/bin/nix-builder --prefix PATH : ${
-        lib.makeBinPath [
-          pkgs.git
-          pkgs.nix
-          pkgs.nixos-rebuild
-        ]
-      }
-    '';
-  };
-in
 {
   imports = [ ];
 
@@ -66,7 +20,7 @@ in
 
   config = lib.mkIf config.me.hydra.enable {
     environment.systemPackages = with pkgs; [
-      nix_builder
+      nix_builder.packages.x86_64-linux.default
       sqlite # For manually inspecting the database.
     ];
 
@@ -142,7 +96,7 @@ in
           IFS=$'\n\t'
           DIR="$( cd "$( dirname "''${BASH_SOURCE[0]}" )" && pwd )"
 
-          NIX_REMOTE='local?root=/.disk/root' RUST_BACKTRACE=1 RUST_LOG=nix_builder=DEBUG ${nix_builder}/bin/nix-builder build --config ${./files/nix_builder.toml} ${builtins.concatStringsSep " " build_flags}
+          NIX_REMOTE='local?root=/.disk/root' RUST_BACKTRACE=1 RUST_LOG=nix_builder=DEBUG ${nix_builder.packages.x86_64-linux.default}/bin/nix-builder build --config ${./files/nix_builder.toml} ${builtins.concatStringsSep " " build_flags}
         '';
         restartIfChanged = false;
         serviceConfig = {