1 files changed, 17 insertions, 0 deletions
diff --git a/internal/praefect/grpc-proxy/proxy/handler.go b/internal/praefect/grpc-proxy/proxy/handler.go
index aeac70181..743aedf8a 100644
--- a/internal/praefect/grpc-proxy/proxy/handler.go
+++ b/internal/praefect/grpc-proxy/proxy/handler.go
@@ -10,6 +10,7 @@ package proxy
 import (
 	"context"
 	"errors"
+	"fmt"
 	"io"
 
 	"gitlab.com/gitlab-org/gitaly/internal/middleware/sentryhandler"
@@ -96,6 +97,20 @@ type streamAndDestination struct {
 	cancel      func()
 }
 
+// failDestinationWithErrors marks all of the destinations in the StreamParameters as
+// having failed with the given error.
+func failDestinationsWithError(params *StreamParameters, err error) {
+	if params.Primary().ErrHandler != nil {
+		_ = params.Primary().ErrHandler(err)
+	}
+
+	for _, secondary := range params.Secondaries() {
+		if secondary.ErrHandler != nil {
+			_ = secondary.ErrHandler(err)
+		}
+	}
+}
+
 // handler is where the real magic of proxying happens.
 // It is invoked like any gRPC server stream and uses the gRPC server framing to get and receive bytes from the wire,
 // forwarding it to a ClientStream established against the relevant ClientConn.
@@ -127,6 +142,7 @@ func (s *handler) handler(srv interface{}, serverStream grpc.ServerStream) (fina
 
 	primaryClientStream, err := grpc.NewClientStream(clientCtx, clientStreamDescForProxying, params.Primary().Conn, fullMethodName, params.CallOptions()...)
 	if err != nil {
+		failDestinationsWithError(params, fmt.Errorf("initiate primary stream: %w", err))
 		return err
 	}
 
@@ -143,6 +159,7 @@ func (s *handler) handler(srv interface{}, serverStream grpc.ServerStream) (fina
 
 		secondaryClientStream, err := grpc.NewClientStream(clientCtx, clientStreamDescForProxying, destination.Conn, fullMethodName, params.CallOptions()...)
 		if err != nil {
+			failDestinationsWithError(params, fmt.Errorf("initiate secondary stream: %w", err))
 			return err
 		}
 		secondaryStreams = append(secondaryStreams, streamAndDestination{