feat(nix): add treefmt-nix

README.adoc

@@ -24,6 +24,7 @@ link:https://nixos.org[nix] is used to run tasks and manage other tools.
 * List available tasks: `+nix flake show+`
 * Invoke a task: `+nix run .#<task>+`
 * Enter a development shell: `+nix develop+`
+* Run linters: `+nix flake check+`
 
 == License
 

flake.lock

@@ -37,7 +37,8 @@
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "treefmt-nix": "treefmt-nix"
       }
     },
     "systems": {
@@ -54,6 +55,26 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1699786194,
+        "narHash": "sha256-3h3EH1FXQkIeAuzaWB+nK0XK54uSD46pp+dMD3gAcB4=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "e82f32aa7f06bbbd56d7b12186d555223dc399d1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -18,13 +18,21 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     flake-utils.url = "github:numtide/flake-utils";
+
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
-  outputs = inputs @ { self, nixpkgs, flake-utils, ... }:
+  outputs = { self, nixpkgs, flake-utils, treefmt-nix, ... }:
     flake-utils.lib.eachDefaultSystem (system:
       let
+        inherit (nixpkgs) lib;
         pkgs = nixpkgs.legacyPackages."${system}";
 
+        treefmtEval = treefmt-nix.lib.evalModule pkgs ./treefmt.nix;
+
         shellHook = ''
           export NIX_CONFIG="experimental-features = nix-command flakes"
           export GOTOOLCHAIN=local
@@ -44,12 +52,12 @@
           (builtins.map
             (x: {
               name = x;
-              value = nixpkgs.lib.genAttrs
+              value = lib.genAttrs
                 (
                   builtins.map
                     (y: x + ":" + y)
                     (builtins.attrNames
-                      (nixpkgs.lib.attrsets.filterAttrs (k: v: v == "directory")
+                      (lib.attrsets.filterAttrs (k: v: v == "directory")
                         (builtins.readDir ./stacks)
                       )
                     )
@@ -57,8 +65,6 @@
             }) [ "plan" "up" ]);
       in
       {
-        formatter = pkgs.nixpkgs-fmt;
-
         # `pulumi up` -> nix run .#up:<stack>
         apps = forPulumi.up
           (target:
@@ -86,25 +92,39 @@
                 '';
               };
             }
-          )
-        # Other tasks
-        // {
-          lint = with pkgs; flake-utils.lib.mkApp {
-            drv = writeShellScriptBin "lint" ''
-              ${golangci-lint}/bin/golangci-lint run
+          );
+
+        checks = {
+          golangci = with pkgs; runCommandLocal "golangci-check"
+            {
+              buildInputs = [ golangci-lint go ];
+              meta.description = "Run golangci-lint against the code base";
+            }
+            ''
+              export HOME=$TMPDIR
+              export LANG=C.UTF-8
+              export LC_ALL=C.UTF-8
+
+              cd "${self}"
+              golangci-lint run
+
+              # Require to pass mkDerivation
+              touch $out
             '';
-          };
+
+          treefmt = treefmtEval.config.build.check self;
         };
 
+        formatter = treefmtEval.config.build.wrapper;
+
         devShells.default = with pkgs; mkShell {
+          inherit shellHook;
           nativeBuildInputs = pulumiInputs ++ [
             git
-            golangci-lint
             nix
             sops
             vim
           ];
-          shellHook = shellHook;
         };
       }
     );

treefmt.nix

@@ -0,0 +1,22 @@
+_:
+{
+  projectRootFile = ".git/config";
+
+  # List of formatters: https://github.com/numtide/treefmt-nix/tree/main/programs
+  programs = builtins.listToAttrs
+    (
+      builtins.map
+        (x: {
+          name = x;
+          value.enable = true;
+        })
+        [
+          "gofumpt"
+          "nixpkgs-fmt"
+          "shellcheck"
+          "shfmt"
+          "statix"
+          "taplo"
+        ]
+    );
+}