feat: Add queue size multiplier config to BulkIndexer

esutil/bulk_indexer.go

@@ -54,9 +54,10 @@ type BulkIndexer interface {
 
 // BulkIndexerConfig represents configuration of the indexer.
 type BulkIndexerConfig struct {
-	NumWorkers    int           // The number of workers. Defaults to runtime.NumCPU().
-	FlushBytes    int           // The flush threshold in bytes. Defaults to 5MB.
-	FlushInterval time.Duration // The flush threshold as duration. Defaults to 30sec.
+	NumWorkers          int           // The number of workers. Defaults to runtime.NumCPU().
+	FlushBytes          int           // The flush threshold in bytes. Defaults to 5MB.
+	FlushInterval       time.Duration // The flush threshold as duration. Defaults to 30sec.
+	QueueSizeMultiplier int           // The multiplier on the size of the worker queue. Defaults to 1.
 
 	Client      esapi.Transport         // The Elasticsearch client.
 	Decoder     BulkResponseJSONDecoder // A custom JSON decoder.
@@ -289,18 +290,22 @@ func NewBulkIndexer(cfg BulkIndexerConfig) (BulkIndexer, error) {
 		cfg.Decoder = defaultJSONDecoder{}
 	}
 
-	if cfg.NumWorkers == 0 {
+	if cfg.NumWorkers <= 0 {
 		cfg.NumWorkers = runtime.NumCPU()
 	}
 
-	if cfg.FlushBytes == 0 {
+	if cfg.FlushBytes <= 0 {
 		cfg.FlushBytes = 5e+6
 	}
 
-	if cfg.FlushInterval == 0 {
+	if cfg.FlushInterval <= 0 {
 		cfg.FlushInterval = 30 * time.Second
 	}
 
+	if cfg.QueueSizeMultiplier <= 0 {
+		cfg.QueueSizeMultiplier = 1
+	}
+
 	bi := bulkIndexer{
 		config: cfg,
 		stats:  &bulkIndexerStats{},
@@ -371,7 +376,7 @@ func (bi *bulkIndexer) Stats() BulkIndexerStats {
 
 // init initializes the bulk indexer.
 func (bi *bulkIndexer) init() {
-	bi.queue = make(chan BulkIndexerItem, bi.config.NumWorkers)
+	bi.queue = make(chan BulkIndexerItem, bi.config.NumWorkers*bi.config.QueueSizeMultiplier)
 
 	for i := 1; i <= bi.config.NumWorkers; i++ {
 		bi.wg.Add(1)

esutil/bulk_indexer_internal_test.go

@@ -186,6 +186,103 @@ func TestBulkIndexer(t *testing.T) {
 		}
 	})
 
+	t.Run("BulkIndexerConfig.QueueSizeMultiplier", func(t *testing.T) {
+		tests := []struct {
+			name                string
+			numWorkers          int
+			queueSizeMultiplier int
+			expectedQueueCap    int
+		}{
+			{
+				name:                "Default QueueSizeMultiplier with 1 worker",
+				numWorkers:          1,
+				queueSizeMultiplier: 0,
+				expectedQueueCap:    1,
+			},
+			{
+				name:                "Default QueueSizeMultiplier with 2 workers",
+				numWorkers:          2,
+				queueSizeMultiplier: 0,
+				expectedQueueCap:    2,
+			},
+			{
+				name:                "QueueSizeMultiplier=2 with 1 worker",
+				numWorkers:          1,
+				queueSizeMultiplier: 2,
+				expectedQueueCap:    2,
+			},
+			{
+				name:                "QueueSizeMultiplier=5 with 1 worker",
+				numWorkers:          1,
+				queueSizeMultiplier: 5,
+				expectedQueueCap:    5,
+			},
+			{
+				name:                "QueueSizeMultiplier=10 with 1 worker",
+				numWorkers:          1,
+				queueSizeMultiplier: 10,
+				expectedQueueCap:    10,
+			},
+			{
+				name:                "QueueSizeMultiplier=1 with 4 workers",
+				numWorkers:          4,
+				queueSizeMultiplier: 1,
+				expectedQueueCap:    4,
+			},
+			{
+				name:                "QueueSizeMultiplier=2 with 4 workers",
+				numWorkers:          4,
+				queueSizeMultiplier: 2,
+				expectedQueueCap:    8,
+			},
+			{
+				name:                "QueueSizeMultiplier=5 with 3 workers",
+				numWorkers:          3,
+				queueSizeMultiplier: 5,
+				expectedQueueCap:    15,
+			},
+			{
+				name:                "QueueSizeMultiplier=-1 with 1 worker",
+				numWorkers:          1,
+				queueSizeMultiplier: -1,
+				expectedQueueCap:    1,
+			},
+		}
+
+		for _, tt := range tests {
+			tt := tt
+			t.Run(tt.name, func(t *testing.T) {
+				es, err := elasticsearch.NewClient(elasticsearch.Config{Transport: &mockTransport{}})
+				if err != nil {
+					t.Fatalf("Unexpected error: %s", err)
+				}
+
+				cfg := BulkIndexerConfig{
+					NumWorkers:          tt.numWorkers,
+					QueueSizeMultiplier: tt.queueSizeMultiplier,
+					Client:              es,
+				}
+
+				bi, err := NewBulkIndexer(cfg)
+				if err != nil {
+					t.Fatalf("Unexpected error: %s", err)
+				}
+
+				bir, ok := bi.(*bulkIndexer)
+				if !ok {
+					t.Fatalf("Unexpected type: %T", bi)
+				}
+
+				if queueCap := cap(bir.queue); queueCap != tt.expectedQueueCap {
+					t.Errorf("Unexpected queue capacity: want=%d, got=%d", tt.expectedQueueCap, queueCap)
+				}
+
+				// Clean up
+				_ = bi.Close(context.Background())
+			})
+		}
+	})
+
 	t.Run("Add() Timeout", func(t *testing.T) {
 		es, _ := elasticsearch.NewClient(elasticsearch.Config{Transport: &mockTransport{}})
 		bi, _ := NewBulkIndexer(BulkIndexerConfig{NumWorkers: 1, Client: es})