[exporter] Flip on queue batcher (#11637)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

This PR solves
#10368.

Previously we use a pushing model between the queue and the batch,
resulting the batch size to be constrained by the
`sending_queue.num_consumers`, because the batch cannot accumulate more
than `sending_queue.num_consumers` blocked goroutines provide.

This PR changes it to a pulling model. We read from the queue until
threshold is met or timeout, then allocate a worker to asynchronously
send out the request.

<!-- Issue number if applicable -->
#### Link to tracking issue
Fixes
#10368
#8122

---------

Co-authored-by: Dmitrii Anoshin <[email protected]>

.chloggen/11637-exporter-queue-batcher.yaml

@@ -0,0 +1,28 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: exporterqueue
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Introduce a feature gate exporter.UsePullingBasedExporterQueueBatcher to use the new pulling model in exporter queue batching.
+
+# One or more tracking issues or pull requests related to the change
+issues: [8122, 10368]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+  If both queuing and batching is enabled for exporter, we now use a pulling model instead of a
+  pushing model. num_consumer in queue configuration is now used to specify the maximum number of
+  concurrent workers that are sending out the request. 
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

exporter/exporterhelper/internal/base_exporter.go

@@ -26,9 +26,9 @@ import (
 )
 
 var usePullingBasedExporterQueueBatcher = featuregate.GlobalRegistry().MustRegister(
-	"telemetry.UsePullingBasedExporterQueueBatcher",
-	featuregate.StageBeta,
-	featuregate.WithRegisterFromVersion("v0.114.0"),
+	"exporter.UsePullingBasedExporterQueueBatcher",
+	featuregate.StageAlpha,
+	featuregate.WithRegisterFromVersion("v0.115.0"),
 	featuregate.WithRegisterDescription("if set to true, turns on the pulling-based exporter queue bathcer"),
 )
 
@@ -102,13 +102,14 @@ func NewBaseExporter(set exporter.Settings, signal pipeline.Signal, osf ObsrepSe
 				ExporterSettings: be.Set,
 			},
 			be.queueCfg)
-		be.QueueSender = NewQueueSender(q, be.Set, be.queueCfg.NumConsumers, be.ExportFailureMessage, be.Obsrep)
+		be.QueueSender = NewQueueSender(q, be.Set, be.queueCfg.NumConsumers, be.ExportFailureMessage, be.Obsrep, be.BatcherCfg)
 		for _, op := range options {
 			err = multierr.Append(err, op(be))
 		}
 	}
 
-	if be.BatcherCfg.Enabled {
+	if !usePullingBasedExporterQueueBatcher.IsEnabled() && be.BatcherCfg.Enabled ||
+		usePullingBasedExporterQueueBatcher.IsEnabled() && be.BatcherCfg.Enabled && !be.queueCfg.Enabled {
 		bs := NewBatchSender(be.BatcherCfg, be.Set)
 		be.BatchSender = bs
 	}

exporter/exporterhelper/internal/batch_sender_test.go

@@ -158,7 +158,6 @@ func TestBatchSender_BatchExportError(t *testing.T) {
 			assert.Eventually(t, func() bool {
 				return sink.requestsCount.Load() == tt.expectedRequests &&
 					sink.itemsCount.Load() == tt.expectedItems &&
-					be.BatchSender.(*BatchSender).activeRequests.Load() == 0 &&
 					be.QueueSender.(*QueueSender).queue.Size() == 0
 			}, 100*time.Millisecond, 10*time.Millisecond)
 		})

exporter/exporterhelper/internal/queue_sender.go

@@ -15,6 +15,7 @@ import (
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/exporter"
+	"go.opentelemetry.io/collector/exporter/exporterbatcher"
 	"go.opentelemetry.io/collector/exporter/exporterqueue"
 	"go.opentelemetry.io/collector/exporter/internal"
 	"go.opentelemetry.io/collector/exporter/internal/queue"
@@ -71,30 +72,41 @@ type QueueSender struct {
 	queue          exporterqueue.Queue[internal.Request]
 	numConsumers   int
 	traceAttribute attribute.KeyValue
+	batcher        queue.Batcher
 	consumers      *queue.Consumers[internal.Request]
 
 	obsrep     *ObsReport
 	exporterID component.ID
 }
 
-func NewQueueSender(q exporterqueue.Queue[internal.Request], set exporter.Settings, numConsumers int,
-	exportFailureMessage string, obsrep *ObsReport) *QueueSender {
+func NewQueueSender(
+	q exporterqueue.Queue[internal.Request],
+	set exporter.Settings,
+	numConsumers int,
+	exportFailureMessage string,
+	obsrep *ObsReport,
+	batcherCfg exporterbatcher.Config) *QueueSender {
 	qs := &QueueSender{
 		queue:          q,
 		numConsumers:   numConsumers,
 		traceAttribute: attribute.String(ExporterKey, set.ID.String()),
 		obsrep:         obsrep,
 		exporterID:     set.ID,
 	}
-	consumeFunc := func(ctx context.Context, req internal.Request) error {
+
+	exportFunc := func(ctx context.Context, req internal.Request) error {
 		err := qs.NextSender.Send(ctx, req)
 		if err != nil {
 			set.Logger.Error("Exporting failed. Dropping data."+exportFailureMessage,
 				zap.Error(err), zap.Int("dropped_items", req.ItemsCount()))
 		}
 		return err
 	}
-	qs.consumers = queue.NewQueueConsumers[internal.Request](q, numConsumers, consumeFunc)
+	if usePullingBasedExporterQueueBatcher.IsEnabled() {
+		qs.batcher, _ = queue.NewBatcher(batcherCfg, q, exportFunc, numConsumers)
+	} else {
+		qs.consumers = queue.NewQueueConsumers[internal.Request](q, numConsumers, exportFunc)
+	}
 	return qs
 }
 
@@ -103,8 +115,15 @@ func (qs *QueueSender) Start(ctx context.Context, host component.Host) error {
 	if err := qs.queue.Start(ctx, host); err != nil {
 		return err
 	}
-	if err := qs.consumers.Start(ctx, host); err != nil {
-		return err
+
+	if usePullingBasedExporterQueueBatcher.IsEnabled() {
+		if err := qs.batcher.Start(ctx, host); err != nil {
+			return err
+		}
+	} else {
+		if err := qs.consumers.Start(ctx, host); err != nil {
+			return err
+		}
 	}
 
 	dataTypeAttr := attribute.String(DataTypeKey, qs.obsrep.Signal.String())
@@ -123,6 +142,9 @@ func (qs *QueueSender) Shutdown(ctx context.Context) error {
 	if err := qs.queue.Shutdown(ctx); err != nil {
 		return err
 	}
+	if usePullingBasedExporterQueueBatcher.IsEnabled() {
+		return qs.batcher.Shutdown(ctx)
+	}
 	return qs.consumers.Shutdown(ctx)
 }
 

exporter/exporterhelper/internal/queue_sender_test.go

@@ -19,6 +19,7 @@ import (
 	"go.opentelemetry.io/collector/component/componenttest"
 	"go.opentelemetry.io/collector/config/configretry"
 	"go.opentelemetry.io/collector/exporter"
+	"go.opentelemetry.io/collector/exporter/exporterbatcher"
 	"go.opentelemetry.io/collector/exporter/exporterqueue"
 	"go.opentelemetry.io/collector/exporter/exportertest"
 	"go.opentelemetry.io/collector/exporter/internal"
@@ -540,7 +541,7 @@ func TestQueueSenderNoStartShutdown(t *testing.T) {
 				ExporterCreateSettings: exportertest.NewNopSettings(),
 			})
 			require.NoError(t, err)
-			qs := NewQueueSender(queue, set, 1, "", obsrep)
+			qs := NewQueueSender(queue, set, 1, "", obsrep, exporterbatcher.NewDefaultConfig())
 			assert.NoError(t, qs.Shutdown(context.Background()))
 		})
 	}

exporter/internal/queue/default_batcher.go

@@ -132,6 +132,11 @@ func (qb *DefaultBatcher) startTimeBasedFlushingGoroutine() {
 
 // Start starts the goroutine that reads from the queue and flushes asynchronously.
 func (qb *DefaultBatcher) Start(_ context.Context, _ component.Host) error {
+	// maxWorker being -1 means batcher is disabled. This is for testing queue sender metrics.
+	if qb.maxWorkers == -1 {
+		return nil
+	}
+
 	qb.startWorkerPool()
 	qb.shutdownCh = make(chan bool, 1)
 

exporter/internal/queue/disabled_batcher.go

@@ -17,6 +17,11 @@ type DisabledBatcher struct {
 
 // Start starts the goroutine that reads from the queue and flushes asynchronously.
 func (qb *DisabledBatcher) Start(_ context.Context, _ component.Host) error {
+	// maxWorker being -1 means batcher is disabled. This is for testing queue sender metrics.
+	if qb.maxWorkers == -1 {
+		return nil
+	}
+
 	qb.startWorkerPool()
 
 	// This goroutine reads and then flushes.