feat(server): Use hash of Nixery source as version

Uses a hash of Nixery's sources as the version displayed when Nixery
launches or logs an error. This makes it possible to distinguish
between errors logged from different versions.

The source hashes should be reproducible between different checkouts
of the same source tree.

1 files changed, 32 insertions, 8 deletions

diff --git a/tools/nixery/server/default.nix b/tools/nixery/server/default.nix
index 573447a6c3df..d497f106b02e 100644
--- a/tools/nixery/server/default.nix
+++ b/tools/nixery/server/default.nix
@@ -12,21 +12,45 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-{ buildGoPackage, lib }:
+{ buildGoPackage, go, lib, srcHash }:
 
-buildGoPackage {
+buildGoPackage rec {
   name = "nixery-server";
   goDeps = ./go-deps.nix;
   src = ./.;
 
   goPackagePath = "github.com/google/nixery/server";
-
-  # Enable checks and configure check-phase to include vet:
   doCheck = true;
-  preCheck = ''
-    for pkg in $(getGoDirs ""); do
-      buildGoDir vet "$pkg"
-    done
+
+  # The following phase configurations work around the overengineered
+  # Nix build configuration for Go.
+  #
+  # All I want this to do is produce a binary in the standard Nix
+  # output path, so pretty much all the phases except for the initial
+  # configuration of the "dependency forest" in $GOPATH have been
+  # overridden.
+  #
+  # This is necessary because the upstream builder does wonky things
+  # with the build arguments to the compiler, but I need to set some
+  # complex flags myself
+
+  outputs = [ "out" ];
+  preConfigure = "bin=$out";
+  buildPhase = ''
+    runHook preBuild
+    runHook renameImport
+
+    export GOBIN="$out/bin"
+    go install -ldflags "-X main.version=$(cat ${srcHash})" ${goPackagePath}
+  '';
+
+  fixupPhase = ''
+    remove-references-to -t ${go} $out/bin/server
+  '';
+
+  checkPhase = ''
+    go vet ${goPackagePath}
+    go test ${goPackagePath}
   '';
 
   meta = {