Change FindTag err when tag not found to NotFound

What
---
Update the error message to be `Not Found` rather then `Internal` when a
tag is not found.

Why
---
We burn through our error budget when a single user sends a bunch of
requests to tags that don't exist because we classify the error as
`Internal`, instead it should be `NotFound`.

Reference: https://gitlab.com/gitlab-org/gitaly/-/issues/4366
Signed-off-by: Steve Azzopardi <sazzopardi@gitlab.com>

2 files changed, 13 insertions, 1 deletions

diff --git a/internal/gitaly/service/ref/refs.go b/internal/gitaly/service/ref/refs.go
index 19e532dc0..c8b1ba34d 100644
--- a/internal/gitaly/service/ref/refs.go
+++ b/internal/gitaly/service/ref/refs.go
@@ -257,7 +257,7 @@ func (s *server) findTag(ctx context.Context, repo git.RepositoryExecutor, tagNa
 			return nil, err
 		}
 	} else {
-		return nil, errors.New("no tag found")
+		return nil, helper.ErrNotFoundf("no tag found")
 	}
 
 	if err = tagCmd.Wait(); err != nil {
diff --git a/internal/gitaly/service/ref/refs_test.go b/internal/gitaly/service/ref/refs_test.go
index aa4e0faff..2028563e9 100644
--- a/internal/gitaly/service/ref/refs_test.go
+++ b/internal/gitaly/service/ref/refs_test.go
@@ -1212,3 +1212,15 @@ func TestInvalidFindTagRequest(t *testing.T) {
 		})
 	}
 }
+
+func TestNotFoundFindTagRequest(t *testing.T) {
+	t.Parallel()
+
+	ctx := testhelper.Context(t)
+	_, repoProto, _, client := setupRefService(ctx, t)
+
+	rpcRequest := &gitalypb.FindTagRequest{Repository: repoProto, TagName: []byte("not-found")}
+
+	_, err := client.FindTag(ctx, rpcRequest)
+	testhelper.RequireGrpcError(t, err, helper.ErrNotFoundf("no tag found"))
+}