[CRE] Reduce noisy error in shard index mapper (#23885)

[CRE] Reduce noisy errors in shard index mapper

Author: bolekk

core/services/registrysyncer/v2/syncer.go

@@ -377,7 +377,7 @@ func (s *registrySyncer) Sync(ctx context.Context, isInitialSync bool) error {
 	for _, listener := range s.listeners {
 		lrCopy := registry.DeepCopyRegistryMetadata(latestRegistry)
 		if err := listener.OnNewRegistry(ctx, &lrCopy); err != nil {
-			s.lggr.Errorf("error calling launcher: %s", err)
+			s.lggr.Errorf("error calling OnNewRegistry on a registrysyncer listener: %s", err)
 			s.metrics.incrementLauncherFailureCounter(ctx)
 		}
 	}

core/services/workflows/shardownership/shard_index_mapper.go

@@ -2,7 +2,6 @@ package shardownership
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"slices"
 	"strings"
@@ -45,7 +44,8 @@ func (s *ShardIndexMapper) OnNewRegistry(ctx context.Context, reg *registry.Regi
 		return fmt.Errorf("failed to resolve local node: %w", err)
 	}
 	if localNode.WorkflowDON.ID == 0 {
-		return errors.New("local node does not belong to a workflow DON")
+		s.lggr.Info("local node does not belong to a workflow DON, skipping shard index mapping")
+		return nil
 	}
 
 	namePrefix := shardGroupNamePrefix(localNode.WorkflowDON.Name)

core/services/workflows/shardownership/shard_index_mapper_test.go

@@ -184,7 +184,7 @@ func TestShardIndexMapper_ErrorsWhenLocalDonHasNoFamilies(t *testing.T) {
 	assert.Contains(t, err.Error(), "no workflow DONs found")
 }
 
-func TestShardIndexMapper_ErrorsWhenLocalNodeNotInAnyWorkflowDon(t *testing.T) {
+func TestShardIndexMapper_SkipsWhenLocalNodeNotInAnyWorkflowDon(t *testing.T) {
 	t.Parallel()
 
 	me := makePeerID(1)
@@ -194,9 +194,8 @@ func TestShardIndexMapper_ErrorsWhenLocalNodeNotInAnyWorkflowDon(t *testing.T) {
 	)
 
 	idx := NewShardIndexMapper(logger.Test(t))
-	err := idx.OnNewRegistry(t.Context(), reg)
-	require.Error(t, err)
-	assert.Contains(t, err.Error(), "does not belong to a workflow DON")
+	require.NoError(t, idx.OnNewRegistry(t.Context(), reg))
+	assert.Nil(t, idx.DonByShardIndex(t.Context(), 0))
 }
 
 func TestShardIndexMapper_ErrorsOnMultiDigitShardSuffix(t *testing.T) {