Add nix flakes to go repo template

Signed-off-by: Milos Gajdos <[email protected]>

Author: milosgajdos

default.nix

@@ -0,0 +1,22 @@
+{ pkgs ? (
+    let
+      inherit (builtins) fetchTree fromJSON readFile;
+      inherit ((fromJSON (readFile ./flake.lock)).nodes) nixpkgs gomod2nix;
+    in
+    import (fetchTree nixpkgs.locked) {
+      overlays = [
+        (import "${fetchTree gomod2nix.locked}/overlay.nix")
+      ];
+    }
+  )
+, buildGoApplication ? pkgs.buildGoApplication
+}:
+
+buildGoApplication {
+  pname = "go-app";
+  version = "0.1";
+  pwd = ./.;
+  src = ./.;
+  modules = ./gomod2nix.toml;
+  doCheck = false;
+}

flake.lock

@@ -0,0 +1,29 @@
+{
+  description = "A basic gomod2nix flake";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.gomod2nix.url = "github:nix-community/gomod2nix";
+  inputs.gomod2nix.inputs.nixpkgs.follows = "nixpkgs";
+  inputs.gomod2nix.inputs.flake-utils.follows = "flake-utils";
+
+  outputs = { self, nixpkgs, flake-utils, gomod2nix }:
+    (flake-utils.lib.eachDefaultSystem
+      (system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+
+          # The current default sdk for macOS fails to compile go projects, so we use a newer one for now.
+          # This has no effect on other platforms.
+          callPackage = pkgs.darwin.apple_sdk_11_0.callPackage or pkgs.callPackage;
+        in
+        {
+          packages.default = callPackage ./. {
+            inherit (gomod2nix.legacyPackages.${system}) buildGoApplication;
+          };
+          devShells.default = callPackage ./shell.nix {
+            inherit (gomod2nix.legacyPackages.${system}) mkGoEnv gomod2nix;
+          };
+        })
+    );
+}

flake.nix

@@ -0,0 +1,3 @@
+schema = 3
+
+[mod]

gomod2nix.toml

@@ -0,0 +1,26 @@
+{ pkgs ? (
+    let
+      inherit (builtins) fetchTree fromJSON readFile;
+      inherit ((fromJSON (readFile ./flake.lock)).nodes) nixpkgs gomod2nix;
+    in
+    import (fetchTree nixpkgs.locked) {
+      overlays = [
+        (import "${fetchTree gomod2nix.locked}/overlay.nix")
+      ];
+    }
+  )
+, mkGoEnv ? pkgs.mkGoEnv
+, gomod2nix ? pkgs.gomod2nix
+, golangci-lint ? pkgs.golangci-lint
+}:
+
+let
+  goEnv = mkGoEnv { pwd = ./.; };
+in
+pkgs.mkShell {
+  packages = [
+    goEnv
+    gomod2nix
+    golangci-lint
+  ];
+}