[exporterhelper] Add WithRequestQueue option to the exporter

.chloggen/exporter-helper-v2.yaml

@@ -0,0 +1,34 @@
+# 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: exporter/exporterhelper
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add API for enabling queue in the new exporter helpers.
+
+# One or more tracking issues or pull requests related to the change
+issues: [7874]
+
+# (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: |
+  The following experimental API is introduced in exporter/exporterhelper package:
+    - `WithRequestQueue`: a new exporter helper option for using a queue.
+    - queue.Queue: an interface for queue implementations.
+    - queue.Factory: a queue factory interface, implementations of this interface are intended to be used with WithRequestQueue option.
+    - queue.Settings: queue factory settings.
+    - queue.Config: common configuration for queue implementations.
+    - queue.NewDefaultConfig: a function for creating a default queue configuration.
+    - queue/memoryqueue.NewFactory: a new factory for creating a memory queue.
+    - queue/memoryqueue.Config: a configuration for the memory queue factory.
+    - queue/memoryqueue.NewDefaultConfig: a function for creating a default memory queue configuration.
+    All the new APIs are intended to be used by exporters that operate over client-provided requests instead of pdata.
+
+# 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: [api]

exporter/exporterhelper/common.go

@@ -9,63 +9,52 @@ import (
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/exporter"
-	"go.opentelemetry.io/collector/exporter/exporterhelper/internal"
+	intrequest "go.opentelemetry.io/collector/exporter/exporterhelper/internal/request"
+	"go.opentelemetry.io/collector/exporter/exporterhelper/queue"
+	"go.opentelemetry.io/collector/exporter/exporterhelper/queue/persistentqueue"
+	"go.opentelemetry.io/collector/exporter/exporterhelper/request"
 )
 
 // requestSender is an abstraction of a sender for a request independent of the type of the data (traces, metrics, logs).
 type requestSender interface {
-	start(ctx context.Context, host component.Host, set exporter.CreateSettings) error
-	shutdown()
-	send(req internal.Request) error
-	setNextSender(nextSender requestSender)
-}
-
-type baseRequestSender struct {
-	nextSender requestSender
-}
-
-var _ requestSender = (*baseRequestSender)(nil)
-
-func (b *baseRequestSender) start(context.Context, component.Host, exporter.CreateSettings) error {
-	return nil
-}
-
-func (b *baseRequestSender) shutdown() {}
-
-func (b *baseRequestSender) send(req internal.Request) error {
-	return b.nextSender.send(req)
+	send(req *intrequest.Request) error
 }
 
-func (b *baseRequestSender) setNextSender(nextSender requestSender) {
-	b.nextSender = nextSender
+type starter interface {
+	start(context.Context, component.Host) error
 }
 
-type obsrepSenderFactory func(obsrep *obsExporter) requestSender
-
-// baseRequest is a base implementation for the internal.Request.
-type baseRequest struct {
-	ctx                        context.Context
-	processingFinishedCallback func()
+type shutdowner interface {
+	shutdown()
 }
 
-func (req *baseRequest) Context() context.Context {
-	return req.ctx
+type baseRequestSender struct {
+	sender     requestSender
+	nextSender *baseRequestSender
 }
 
-func (req *baseRequest) SetContext(ctx context.Context) {
-	req.ctx = ctx
+func (b *baseRequestSender) start(ctx context.Context, host component.Host) error {
+	if s, ok := b.sender.(starter); ok {
+		return s.start(ctx, host)
+	}
+	return nil
 }
 
-func (req *baseRequest) SetOnProcessingFinished(callback func()) {
-	req.processingFinishedCallback = callback
+func (b *baseRequestSender) shutdown() {
+	if s, ok := b.sender.(shutdowner); ok {
+		s.shutdown()
+	}
 }
 
-func (req *baseRequest) OnProcessingFinished() {
-	if req.processingFinishedCallback != nil {
-		req.processingFinishedCallback()
+func (b *baseRequestSender) send(req *intrequest.Request) error {
+	if b.sender == nil {
+		return b.nextSender.send(req)
 	}
+	return b.sender.send(req)
 }
 
+type obsrepSenderFactory func(obsrep *obsExporter, nextSender *baseRequestSender) requestSender
+
 // Option apply changes to baseExporter.
 type Option func(*baseExporter)
 
@@ -89,15 +78,15 @@ func WithShutdown(shutdown component.ShutdownFunc) Option {
 // The default TimeoutSettings is 5 seconds.
 func WithTimeout(timeoutSettings TimeoutSettings) Option {
 	return func(o *baseExporter) {
-		o.timeoutSender.cfg = timeoutSettings
+		o.timeoutSender.sender = &timeoutSender{cfg: timeoutSettings}
 	}
 }
 
 // WithRetry overrides the default RetrySettings for an exporter.
 // The default RetrySettings is to disable retries.
 func WithRetry(retrySettings RetrySettings) Option {
 	return func(o *baseExporter) {
-		o.retrySender = newRetrySender(o.set.ID, retrySettings, o.set.Logger, o.onTemporaryFailure)
+		o.retrySender.sender = newRetrySender(o.set.ID, retrySettings, o.set.Logger, o.onTemporaryFailure, o.retrySender.nextSender)
 	}
 }
 
@@ -107,19 +96,32 @@ func WithRetry(retrySettings RetrySettings) Option {
 func WithQueue(config QueueSettings) Option {
 	return func(o *baseExporter) {
 		if o.requestExporter {
-			panic("queueing is not available for the new request exporters yet")
+			panic("this option is not available for the new request exporters, " +
+				"use WithMemoryQueue or WithPersistentQueue instead")
 		}
-		var queue internal.ProducerConsumerQueue
-		if config.Enabled {
-			if config.StorageID == nil {
-				queue = internal.NewBoundedMemoryQueue(config.QueueSize, config.NumConsumers)
-			} else {
-				queue = internal.NewPersistentQueue(config.QueueSize, config.NumConsumers, *config.StorageID, o.marshaler, o.unmarshaler)
-			}
-		}
-		qs := newQueueSender(o.set.ID, o.signal, queue, o.set.Logger)
-		o.queueSender = qs
+		factory := persistentqueue.NewFactory(persistentqueue.Config{
+			Config: queue.Config{
+				Enabled:      config.Enabled,
+				NumConsumers: config.NumConsumers,
+				QueueSize:    config.QueueSize,
+			},
+			StorageID: config.StorageID,
+		}, o.marshaler, o.unmarshaler)
+		qs := newQueueSender(o.set, o.signal, factory, o.queueSender.nextSender)
+		o.setOnTemporaryFailure(qs.onTemporaryFailure)
+		o.queueSender.sender = qs
+	}
+}
+
+// WithRequestQueue enables queueing for an exporter.
+// This option should be used with the new exporter helpers New[Traces|Metrics|Logs]RequestExporter.
+// This API is at the early stage of development and may change without backward compatibility
+// until https://github.com/open-telemetry/opentelemetry-collector/issues/8122 is resolved.
+func WithRequestQueue(queueFactory queue.Factory) Option {
+	return func(o *baseExporter) {
+		qs := newQueueSender(o.set, o.signal, queueFactory, o.queueSender.nextSender)
 		o.setOnTemporaryFailure(qs.onTemporaryFailure)
+		o.queueSender.sender = qs
 	}
 }
 
@@ -138,8 +140,8 @@ type baseExporter struct {
 	component.ShutdownFunc
 
 	requestExporter bool
-	marshaler       internal.RequestMarshaler
-	unmarshaler     internal.RequestUnmarshaler
+	marshaler       request.Marshaler
+	unmarshaler     request.Unmarshaler
 	signal          component.DataType
 
 	set    exporter.CreateSettings
@@ -148,10 +150,10 @@ type baseExporter struct {
 	// Chain of senders that the exporter helper applies before passing the data to the actual exporter.
 	// The data is handled by each sender in the respective order starting from the queueSender.
 	// Most of the senders are optional, and initialized with a no-op path-through sender.
-	queueSender   requestSender
-	obsrepSender  requestSender
-	retrySender   requestSender
-	timeoutSender *timeoutSender // timeoutSender is always initialized.
+	queueSender   *baseRequestSender
+	obsrepSender  *baseRequestSender
+	retrySender   *baseRequestSender
+	timeoutSender *baseRequestSender
 
 	// onTemporaryFailure is a function that is called when the retrySender is unable to send data to the next consumer.
 	onTemporaryFailure onRequestHandlingFinishedFunc
@@ -160,8 +162,8 @@ type baseExporter struct {
 }
 
 // TODO: requestExporter, marshaler, and unmarshaler arguments can be removed when the old exporter helpers will be updated to call the new ones.
-func newBaseExporter(set exporter.CreateSettings, signal component.DataType, requestExporter bool, marshaler internal.RequestMarshaler,
-	unmarshaler internal.RequestUnmarshaler, osf obsrepSenderFactory, options ...Option) (*baseExporter, error) {
+func newBaseExporter(set exporter.CreateSettings, signal component.DataType, requestExporter bool, marshaler request.Marshaler,
+	unmarshaler request.Unmarshaler, osf obsrepSenderFactory, options ...Option) (*baseExporter, error) {
 
 	obsrep, err := newObsExporter(ObsReportSettings{ExporterID: set.ID, ExporterCreateSettings: set}, globalInstruments)
 	if err != nil {
@@ -174,43 +176,36 @@ func newBaseExporter(set exporter.CreateSettings, signal component.DataType, req
 		unmarshaler:     unmarshaler,
 		signal:          signal,
 
-		queueSender:   &baseRequestSender{},
-		obsrepSender:  osf(obsrep),
-		retrySender:   &baseRequestSender{},
-		timeoutSender: &timeoutSender{cfg: NewDefaultTimeoutSettings()},
-
 		set:    set,
 		obsrep: obsrep,
 	}
 
+	// Initialize the chain of senders in the reverse order.
+	be.timeoutSender = &baseRequestSender{sender: &timeoutSender{cfg: NewDefaultTimeoutSettings()}}
+	be.retrySender = &baseRequestSender{nextSender: be.timeoutSender}
+	be.obsrepSender = &baseRequestSender{sender: osf(obsrep, be.retrySender)}
+	be.queueSender = &baseRequestSender{nextSender: be.obsrepSender}
+
 	for _, op := range options {
 		op(be)
 	}
-	be.connectSenders()
 
 	return be, nil
 }
 
 // send sends the request using the first sender in the chain.
-func (be *baseExporter) send(req internal.Request) error {
+func (be *baseExporter) send(req *intrequest.Request) error {
 	return be.queueSender.send(req)
 }
 
-// connectSenders connects the senders in the predefined order.
-func (be *baseExporter) connectSenders() {
-	be.queueSender.setNextSender(be.obsrepSender)
-	be.obsrepSender.setNextSender(be.retrySender)
-	be.retrySender.setNextSender(be.timeoutSender)
-}
-
 func (be *baseExporter) Start(ctx context.Context, host component.Host) error {
 	// First start the wrapped exporter.
 	if err := be.StartFunc.Start(ctx, host); err != nil {
 		return err
 	}
 
 	// If no error then start the queueSender.
-	return be.queueSender.start(ctx, host, be.set)
+	return be.queueSender.start(ctx, host)
 }
 
 func (be *baseExporter) Shutdown(ctx context.Context) error {
@@ -226,7 +221,7 @@ func (be *baseExporter) Shutdown(ctx context.Context) error {
 
 func (be *baseExporter) setOnTemporaryFailure(onTemporaryFailure onRequestHandlingFinishedFunc) {
 	be.onTemporaryFailure = onTemporaryFailure
-	if rs, ok := be.retrySender.(*retrySender); ok {
+	if rs, ok := be.retrySender.sender.(*retrySender); ok {
 		rs.onTemporaryFailure = onTemporaryFailure
 	}
 }

exporter/exporterhelper/common_test.go

@@ -32,8 +32,8 @@ var (
 	}
 )
 
-func newNoopObsrepSender(_ *obsExporter) requestSender {
-	return &baseRequestSender{}
+func newNoopObsrepSender(_ *obsExporter, nextSender *baseRequestSender) requestSender {
+	return &baseRequestSender{nextSender: nextSender}
 }
 
 func TestBaseExporter(t *testing.T) {

exporter/exporterhelper/internal/bounded_memory_queue.go

@@ -11,6 +11,8 @@ import (
 	"sync/atomic"
 
 	"go.opentelemetry.io/collector/component"
+	intrequest "go.opentelemetry.io/collector/exporter/exporterhelper/internal/request"
+	"go.opentelemetry.io/collector/exporter/exporterhelper/queue"
 )
 
 // boundedMemoryQueue implements a producer-consumer exchange similar to a ring buffer queue,
@@ -20,26 +22,28 @@ type boundedMemoryQueue struct {
 	stopWG       sync.WaitGroup
 	size         *atomic.Uint32
 	stopped      *atomic.Bool
-	items        chan Request
+	items        chan *intrequest.Request
 	capacity     uint32
 	numConsumers int
+	callback     func(item *intrequest.Request)
 }
 
 // NewBoundedMemoryQueue constructs the new queue of specified capacity, and with an optional
 // callback for dropped items (e.g. useful to emit metrics).
-func NewBoundedMemoryQueue(capacity int, numConsumers int) ProducerConsumerQueue {
+func NewBoundedMemoryQueue(capacity int, numConsumers int, callback func(item *intrequest.Request)) queue.Queue {
 	return &boundedMemoryQueue{
-		items:        make(chan Request, capacity),
+		items:        make(chan *intrequest.Request, capacity),
 		stopped:      &atomic.Bool{},
 		size:         &atomic.Uint32{},
 		capacity:     uint32(capacity),
 		numConsumers: numConsumers,
+		callback:     callback,
 	}
 }
 
 // StartConsumers starts a given number of goroutines consuming items from the queue
 // and passing them into the consumer callback.
-func (q *boundedMemoryQueue) Start(_ context.Context, _ component.Host, set QueueSettings) error {
+func (q *boundedMemoryQueue) Start(_ context.Context, _ component.Host) error {
 	var startWG sync.WaitGroup
 	for i := 0; i < q.numConsumers; i++ {
 		q.stopWG.Add(1)
@@ -49,7 +53,7 @@ func (q *boundedMemoryQueue) Start(_ context.Context, _ component.Host, set Queu
 			defer q.stopWG.Done()
 			for item := range q.items {
 				q.size.Add(^uint32(0))
-				set.Callback(item)
+				q.callback(item)
 			}
 		}()
 	}
@@ -58,7 +62,7 @@ func (q *boundedMemoryQueue) Start(_ context.Context, _ component.Host, set Queu
 }
 
 // Produce is used by the producer to submit new item to the queue. Returns false in case of queue overflow.
-func (q *boundedMemoryQueue) Produce(item Request) bool {
+func (q *boundedMemoryQueue) Produce(item *intrequest.Request) bool {
 	if q.stopped.Load() {
 		return false
 	}