limithandler: Return structured error on queue timejc-return-structured-error-limits

1 files changed, 14 insertions, 0 deletions

diff --git a/internal/middleware/limithandler/concurrency_limiter.go b/internal/middleware/limithandler/concurrency_limiter.go
index f6587554a..ff26ffb63 100644
--- a/internal/middleware/limithandler/concurrency_limiter.go
+++ b/internal/middleware/limithandler/concurrency_limiter.go
@@ -11,6 +11,8 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/gitaly/config"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/helper"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/metadata/featureflag"
+	"gitlab.com/gitlab-org/gitaly/v14/proto/go/gitalypb"
+	"google.golang.org/protobuf/types/known/durationpb"
 )
 
 // ErrMaxQueueTime indicates a request has reached the maximum time allowed to wait in the
@@ -164,6 +166,18 @@ func (c *ConcurrencyLimiter) Limit(ctx context.Context, lockKey string, f Limite
 	if err != nil {
 		if errors.Is(err, ErrMaxQueueTime) {
 			c.monitor.Dropped(ctx, "max_time")
+
+			errWithDetails, e := helper.ErrWithDetails(
+				helper.ErrUnavailablef("too many requests"),
+				&gitalypb.LimitError{
+					ErrorMessage: "concurrency queue wait time reached",
+					RetryAfter:   durationpb.New(0),
+				},
+			)
+			if e != nil {
+				return nil, err
+			}
+			return nil, errWithDetails
 		}
 		return nil, err
 	}