Fix execute item failure callback on bulk error (#626)

CHANGELOG.md

@@ -19,6 +19,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Fix ISM Allocation field types ([#609](https://github.com/opensearch-project/opensearch-go/pull/609))
 - Fix ISM Error Notification types ([#612](https://github.com/opensearch-project/opensearch-go/pull/612))
 - Fix signer receiving drained body on retries ([#620](https://github.com/opensearch-project/opensearch-go/pull/620))
+- Fix Bulk Index Items not executing failure callbacks on bulk request failure ([#626](https://github.com/opensearch-project/opensearch-go/issues/626))
 
 ### Security
 

opensearchutil/bulk_indexer.go

@@ -503,11 +503,7 @@ func (w *worker) flush(ctx context.Context) error {
 
 	blk, err = w.bi.config.Client.Bulk(ctx, req)
 	if err != nil {
-		atomic.AddUint64(&w.bi.stats.numFailed, uint64(len(w.items)))
-		if w.bi.config.OnError != nil {
-			w.bi.config.OnError(ctx, fmt.Errorf("flush: %w", err))
-		}
-		return fmt.Errorf("flush: %w", err)
+		return w.handleBulkError(ctx, fmt.Errorf("flush: %w", err))
 	}
 
 	for i, blkItem := range blk.Items {
@@ -520,7 +516,7 @@ func (w *worker) flush(ctx context.Context) error {
 		item = w.items[i]
 		// The OpenSearch bulk response contains an array of maps like this:
 		//   [ { "index": { ... } }, { "create": { ... } }, ... ]
-		// We range over the map, to set the first key and value as "op" and "info".
+		// We range over the map, to set the last key and value as "op" and "info".
 		for k, v := range blkItem {
 			op = k
 			info = v
@@ -552,3 +548,21 @@ func (w *worker) flush(ctx context.Context) error {
 
 	return err
 }
+
+func (w *worker) handleBulkError(ctx context.Context, err error) error {
+	atomic.AddUint64(&w.bi.stats.numFailed, uint64(len(w.items)))
+
+	// info (the response item) will be empty since the bulk request failed
+	var info opensearchapi.BulkRespItem
+	for i := range w.items {
+		if item := w.items[i]; item.OnFailure != nil {
+			item.OnFailure(ctx, item, info, err)
+		}
+	}
+
+	if w.bi.config.OnError != nil {
+		w.bi.config.OnError(ctx, err)
+	}
+
+	return err
+}

opensearchutil/bulk_indexer_internal_test.go

@@ -31,6 +31,7 @@ package opensearchutil
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -765,6 +766,78 @@ func TestBulkIndexer(t *testing.T) {
 			})
 		}
 	})
+
+	t.Run("Items Failure Callbacks Executed On Bulk Failure", func(t *testing.T) {
+		client, _ := opensearchapi.NewClient(opensearchapi.Config{
+			Client: opensearch.Config{
+				Transport: &mockTransport{
+					RoundTripFunc: func(request *http.Request) (*http.Response, error) {
+						if request.URL.Path == "/" {
+							return &http.Response{
+								StatusCode: http.StatusOK,
+								Status:     "200 OK",
+								Body:       io.NopCloser(strings.NewReader(infoBody)),
+								Header:     http.Header{"Content-Type": []string{"application/json"}},
+							}, nil
+						}
+
+						return nil, errors.New("simulated bulk request error")
+					},
+				},
+			},
+		})
+
+		bi, _ := NewBulkIndexer(BulkIndexerConfig{
+			NumWorkers: 1,
+			FlushBytes: 1,
+			Client:     client,
+			OnError: func(ctx context.Context, err error) {
+				if err.Error() != "flush: simulated bulk request error" {
+					t.Errorf("Unexpected error: %v", err)
+				}
+			},
+		})
+
+		var (
+			numItems    = 5
+			wg          sync.WaitGroup
+			failedItems int
+		)
+
+		wg.Add(numItems)
+		for i := 0; i < numItems; i++ {
+			err := bi.Add(context.Background(), BulkIndexerItem{
+				Action:     "index",
+				DocumentID: fmt.Sprintf("id_%d", i),
+				Body:       strings.NewReader(fmt.Sprintf(`{"title":"doc_%d"}`, i)),
+				OnFailure: func(ctx context.Context, item BulkIndexerItem, resp opensearchapi.BulkRespItem, err error) {
+					if err.Error() != "flush: simulated bulk request error" {
+						t.Errorf("Unexpected error in OnFailure: %v", err)
+					}
+
+					failedItems++
+					wg.Done()
+				},
+			})
+			if err != nil {
+				t.Fatalf("Unexpected error adding item: %v", err)
+			}
+		}
+
+		if err := bi.Close(context.Background()); err != nil {
+			t.Errorf("Unexpected error: %s", err)
+		}
+
+		wg.Wait()
+
+		if failedItems != numItems {
+			t.Errorf("Expected %d failed items, got %d", numItems, failedItems)
+		}
+
+		if stats := bi.Stats(); stats.NumFailed != uint64(numItems) {
+			t.Errorf("Expected NumFailed to be %d, got %d", numItems, stats.NumFailed)
+		}
+	})
 }
 
 func strPointer(s string) *string {