From 81b81695c2aa7686ae01a5fde4ebe700926298bb Mon Sep 17 00:00:00 2001
From: Pim Kunis <pim@kunis.nl>
Date: Sat, 2 Mar 2024 12:42:00 +0100
Subject: [PATCH] use flake-utils to abstract cpu architectures in some places

---
 flake.lock |  36 ++++++++++++++++-
 flake.nix  | 116 +++++++++++++++++++++++++++--------------------------
 2 files changed, 95 insertions(+), 57 deletions(-)

diff --git a/flake.lock b/flake.lock
index 5b6d7de..d73a01c 100644
--- a/flake.lock
+++ b/flake.lock
@@ -141,6 +141,24 @@
       "inputs": {
         "systems": "systems_3"
       },
+      "locked": {
+        "lastModified": 1709126324,
+        "narHash": "sha256-q6EQdSeUZOG26WelxqkmR7kArjgWCdw5sfJVHPH/7j8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "d465f4819400de7c8d874d50b982301f28a84605",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "flake-utils_3": {
+      "inputs": {
+        "systems": "systems_4"
+      },
       "locked": {
         "lastModified": 1701680307,
         "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
@@ -178,7 +196,7 @@
     },
     "microvm": {
       "inputs": {
-        "flake-utils": "flake-utils_2",
+        "flake-utils": "flake-utils_3",
         "nixpkgs": [
           "nixpkgs"
         ],
@@ -268,6 +286,7 @@
         "deploy-rs": "deploy-rs",
         "disko": "disko",
         "dns": "dns",
+        "flake-utils": "flake-utils_2",
         "microvm": "microvm",
         "nixos-hardware": "nixos-hardware",
         "nixpkgs": "nixpkgs_2",
@@ -335,6 +354,21 @@
         "type": "github"
       }
     },
+    "systems_4": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
     "utils": {
       "inputs": {
         "systems": "systems_2"
diff --git a/flake.nix b/flake.nix
index 58bf968..e0c9a28 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,5 +1,5 @@
 # TODO: good way to improve flake design: https://gist.github.com/lucperkins/437600b6aaaf0e1e8f91fb22fe421234
-# Good tutorial for multiple architectures
+# Good tutorial for multiple architectures: https://ertt.ca/nix/shell-scripts/
 {
   description = "NixOS definitions for our physical servers";
 
@@ -8,6 +8,7 @@
     nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
     deploy-rs.url = "github:serokell/deploy-rs";
     nixos-hardware.url = "github:NixOS/nixos-hardware/master";
+    flake-utils.url = "github:numtide/flake-utils";
 
     disko = {
       url = "github:nix-community/disko";
@@ -31,67 +32,26 @@
   };
 
   outputs =
-    { self, nixpkgs, deploy-rs, disko, agenix, nixpkgs-unstable, dns, microvm, nixos-hardware, ... }:
+    { self, nixpkgs, deploy-rs, disko, agenix, nixpkgs-unstable, dns, microvm, nixos-hardware, flake-utils, ... }:
+    (flake-utils.lib.eachDefaultSystem (system:
     let
-      controllerArch = "x86_64-linux";
-      pkgs = nixpkgs.legacyPackages.${controllerArch};
+      pkgs = nixpkgs.legacyPackages.${system};
       lib = pkgs.lib;
-      pkgs-unstable = nixpkgs-unstable.legacyPackages.${controllerArch};
+      pkgs-unstable = nixpkgs-unstable.legacyPackages.${system};
       machines = (lib.modules.evalModules { modules = [ (import ./nixos/machines) ]; }).config.machines;
-      physicalMachines = lib.filterAttrs (n: v: v.isPhysical) machines;
-      mkNixosSystems = systemDef:
-        builtins.mapAttrs
-          (name: machine:
-            nixpkgs.lib.nixosSystem (systemDef name machine)
-          )
-          physicalMachines;
-      mkDeployNodes = nodeDef:
-        builtins.mapAttrs
-          (name: machine: nodeDef name machine)
-          physicalMachines;
     in
     {
-      formatter.${controllerArch} = pkgs.nixfmt;
+      formatter = pkgs.nixfmt;
 
-      nixosConfigurations = mkNixosSystems (name: machine: {
-        system = machine.arch;
-
-        specialArgs = { inherit machines machine dns microvm disko agenix nixos-hardware; };
-        modules = [
-          ./nixos
-          { networking.hostName = name; }
-        ];
+      checks = deploy-rs.lib.${system}.deployChecks (self.deploy // {
+        nodes = (lib.attrsets.filterAttrs
+          (name: node:
+            machines.${name}.arch == system
+          )
+          self.deploy.nodes);
       });
 
-      deploy = {
-        sshUser = "root";
-        user = "root";
-
-        nodes = mkDeployNodes (name: machine: {
-          hostname = self.nixosConfigurations.${name}.config.networking.fqdn;
-          profiles.system = {
-            remoteBuild = machine.arch != controllerArch;
-            path = deploy-rs.lib."${machine.arch}".activate.nixos
-              self.nixosConfigurations.${name};
-          };
-        });
-      };
-
-      # Deploy-rs' flake checks seem broken for architectures different from the deployment machine.
-      # We skip these here.
-      checks = builtins.mapAttrs
-        (system: deployLib:
-          deployLib.deployChecks (self.deploy // {
-            nodes = (lib.attrsets.filterAttrs
-              (name: node:
-                machines.${name}.arch == controllerArch
-              )
-              self.deploy.nodes);
-          })
-        )
-        deploy-rs.lib;
-
-      packages.${controllerArch}.bootstrap =
+      packages.bootstrap =
         let
           name = "bootstrap";
           buildInputs = with pkgs; [ libsecret coreutils pkgs-unstable.nixos-anywhere ];
@@ -106,9 +66,53 @@
           postBuild = "wrapProgram $out/bin/${name} --set PATH $out/bin";
         };
 
-      apps.${controllerArch}.deploy = {
+      apps.deploy = {
         type = "app";
         program = "${pkgs-unstable.deploy-rs}/bin/deploy";
       };
-    };
+    })) //
+    (
+      let
+        system = "x86_64-linux";
+        pkgs = nixpkgs.legacyPackages.${system};
+        lib = pkgs.lib;
+        machines = (lib.modules.evalModules { modules = [ (import ./nixos/machines) ]; }).config.machines;
+        physicalMachines = lib.filterAttrs (n: v: v.isPhysical) machines;
+        mkNixosSystems = systemDef:
+          builtins.mapAttrs
+            (name: machine:
+              nixpkgs.lib.nixosSystem (systemDef name machine)
+            )
+            physicalMachines;
+        mkDeployNodes = nodeDef:
+          builtins.mapAttrs
+            (name: machine: nodeDef name machine)
+            physicalMachines;
+      in
+      {
+        nixosConfigurations = mkNixosSystems (name: machine: {
+          system = machine.arch;
+
+          specialArgs = { inherit machines machine dns microvm disko agenix nixos-hardware; };
+          modules = [
+            ./nixos
+            { networking.hostName = name; }
+          ];
+        });
+
+        deploy = {
+          sshUser = "root";
+          user = "root";
+
+          nodes = mkDeployNodes (name: machine: {
+            hostname = self.nixosConfigurations.${name}.config.networking.fqdn;
+            profiles.system = {
+              remoteBuild = machine.arch != system;
+              path = deploy-rs.lib."${machine.arch}".activate.nixos
+                self.nixosConfigurations.${name};
+            };
+          });
+        };
+      }
+    );
 }