Add pre-commit gofmt hook.

.gitignore

@@ -4,3 +4,4 @@ env
 files
 /gomod2nix-template
 .direnv
+.pre-commit-config.yaml

flake.lock

@@ -1,5 +1,21 @@
 {
   "nodes": {
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1696426674,
+        "narHash": "sha256-kvjfFW7WAETZlt09AgDn1MrtKzP7t90Vf7vypd3OL1U=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "0f9255e01c2351cc7d116c072cb317785dd33b33",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -18,6 +34,45 @@
         "type": "github"
       }
     },
+    "flake-utils_2": {
+      "inputs": {
+        "systems": "systems_2"
+      },
+      "locked": {
+        "lastModified": 1701680307,
+        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "gitignore": {
+      "inputs": {
+        "nixpkgs": [
+          "pre-commit-hooks",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1703887061,
+        "narHash": "sha256-gGPa9qWNc6eCXT/+Z5/zMkyYOuRZqeFZBDbopNZQkuY=",
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "rev": "43e1aa1308018f37118e34d3a9cb4f5e75dc11d5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "type": "github"
+      }
+    },
     "gomod2nix": {
       "inputs": {
         "flake-utils": [
@@ -57,11 +112,66 @@
         "type": "github"
       }
     },
+    "nixpkgs-stable": {
+      "locked": {
+        "lastModified": 1704874635,
+        "narHash": "sha256-YWuCrtsty5vVZvu+7BchAxmcYzTMfolSPP5io8+WYCg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "3dc440faeee9e889fe2d1b4d25ad0f430d449356",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-23.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1704842529,
+        "narHash": "sha256-OTeQA+F8d/Evad33JMfuXC89VMetQbsU4qcaePchGr4=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "eabe8d3eface69f5bb16c18f8662a702f50c20d5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "flake-utils": "flake-utils_2",
+        "gitignore": "gitignore",
+        "nixpkgs": "nixpkgs_2",
+        "nixpkgs-stable": "nixpkgs-stable"
+      },
+      "locked": {
+        "lastModified": 1708018599,
+        "narHash": "sha256-M+Ng6+SePmA8g06CmUZWi1AjG2tFBX9WCXElBHEKnyM=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "5df5a70ad7575f6601d91f0efec95dd9bc619431",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
         "gomod2nix": "gomod2nix",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks"
       }
     },
     "systems": {
@@ -78,6 +188,21 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -6,8 +6,9 @@
   inputs.gomod2nix.url = "github:nix-community/gomod2nix";
   inputs.gomod2nix.inputs.nixpkgs.follows = "nixpkgs";
   inputs.gomod2nix.inputs.flake-utils.follows = "flake-utils";
+  inputs.pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
 
-  outputs = { self, nixpkgs, flake-utils, gomod2nix }:
+  outputs = { self, nixpkgs, flake-utils, gomod2nix, pre-commit-hooks }:
     (flake-utils.lib.eachDefaultSystem
       (system:
         let
@@ -23,6 +24,7 @@
           };
           devShells.default = callPackage ./shell.nix {
             inherit (gomod2nix.legacyPackages.${system}) mkGoEnv gomod2nix;
+            inherit pre-commit-hooks;
           };
         })
     );

shell.nix

@@ -11,12 +11,20 @@
   )
 , mkGoEnv ? pkgs.mkGoEnv
 , gomod2nix ? pkgs.gomod2nix
+, pre-commit-hooks
 }:
 
 let
   goEnv = mkGoEnv { pwd = ./.; };
+  pre-commit-check = pre-commit-hooks.lib.${pkgs.system}.run {
+      src = ./.;
+      hooks = {
+          gofmt.enable = true;
+      };
+  };
 in
 pkgs.mkShell {
+  inherit (pre-commit-check) shellHook;
   packages = [
     goEnv
     gomod2nix