refactor(build): Pin dependencies using Go modules

Drops the go2nix configuration in favour of pkgs.buildGoModule.

Note that the go.sum file is bloated by issues with cyclic
dependencies in some Google projects, but this large number of
dependencies is not actually built.

tools/nixery/default.nix

@@ -20,7 +20,7 @@
 with pkgs;
 
 let
-  inherit (pkgs) buildGoPackage;
+  inherit (pkgs) buildGoModule;
 
   # Current Nixery commit - this is used as the Nixery version in
   # builds to distinguish errors between deployed versions, see
@@ -32,35 +32,17 @@ let
   #
   # Users should use the nixery-bin derivation below instead as it
   # provides the paths of files needed at runtime.
-  nixery-server = buildGoPackage rec {
+  nixery-server = buildGoModule rec {
     name = "nixery-server";
-    goDeps = ./go-deps.nix;
     src = ./.;
-
-    goPackagePath = "github.com/google/nixery";
     doCheck = true;
 
-    # Simplify the Nix build instructions for Go to just the basics
-    # required to get Nixery up and running with the additional linker
-    # flags required.
-    outputs = [ "out" ];
-    preConfigure = "bin=$out";
-    buildPhase = ''
-      runHook preBuild
-      runHook renameImport
+    # Needs to be updated after every modification of go.mod/go.sum
+    vendorSha256 = "1ff0kfww6fy6pnvyva7x8cc6l1d12aafps48wrkwawk2qjy9a8b9";
 
-      export GOBIN="$out/bin"
-      go install -ldflags "-X main.version=$(cat ${nixery-commit-hash})" ${goPackagePath}
-    '';
-
-    fixupPhase = ''
-      remove-references-to -t ${go} $out/bin/nixery
-    '';
-
-    checkPhase = ''
-      go vet ${goPackagePath}
-      go test ${goPackagePath}
-    '';
+    buildFlagsArray = [
+      "-ldflags=-s -w -X main.version=${nixery-commit-hash}"
+    ];
   };
 in rec {
   # Implementation of the Nix image building logic