Add blocking option to control queue behavior when full (#12090)

Fixes
#5456

Signed-off-by: Bogdan Drutu <[email protected]>

Author: bogdandrutu

.chloggen/add-blocking-option.yaml

@@ -0,0 +1,25 @@
+# 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: exporterhelper
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add blocking option to control queue behavior when full
+
+# One or more tracking issues or pull requests related to the change
+issues: [12090]
+
+# (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:
+
+# 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/README.md

@@ -17,6 +17,7 @@ The following configuration options can be modified:
   - `enabled` (default = true)
   - `num_consumers` (default = 10): Number of consumers that dequeue batches; ignored if `enabled` is `false`
   - `queue_size` (default = 1000): Maximum number of batches kept in memory before dropping; ignored if `enabled` is `false`
+  - `blocking` (default = false): If true blocks until queue has space for the request otherwise returns immediately; ignored if `enabled` is `false`
   User should calculate this as `num_seconds * requests_per_second / requests_per_batch` where:
     - `num_seconds` is the number of seconds to buffer in case of a backend outage
     - `requests_per_second` is the average number of requests per seconds

exporter/exporterhelper/internal/base_exporter.go

@@ -222,6 +222,7 @@ func WithQueue(config QueueConfig) Option {
 			Enabled:      config.Enabled,
 			NumConsumers: config.NumConsumers,
 			QueueSize:    config.QueueSize,
+			Blocking:     config.Blocking,
 		}
 		o.queueFactory = exporterqueue.NewPersistentQueueFactory[internal.Request](config.StorageID, exporterqueue.PersistentQueueSettings[internal.Request]{
 			Marshaler:   o.Marshaler,

exporter/exporterhelper/internal/queue_sender.go

@@ -20,8 +20,6 @@ import (
 	"go.opentelemetry.io/collector/exporter/internal/queue"
 )
 
-const defaultQueueSize = 1000
-
 // QueueConfig defines configuration for queueing batches before sending to the consumerSender.
 type QueueConfig struct {
 	// Enabled indicates whether to not enqueue batches before sending to the consumerSender.
@@ -32,6 +30,9 @@ type QueueConfig struct {
 	NumConsumers int `mapstructure:"num_consumers"`
 	// QueueSize is the maximum number of batches allowed in queue at a given time.
 	QueueSize int `mapstructure:"queue_size"`
+	// Blocking controls the queue behavior when full.
+	// If true it blocks until enough space to add the new request to the queue.
+	Blocking bool `mapstructure:"blocking"`
 	// StorageID if not empty, enables the persistent storage and uses the component specified
 	// as a storage extension for the persistent queue
 	StorageID *component.ID `mapstructure:"storage"`
@@ -45,7 +46,8 @@ func NewDefaultQueueConfig() QueueConfig {
 		// By default, batches are 8192 spans, for a total of up to 8 million spans in the queue
 		// This can be estimated at 1-4 GB worth of maximum memory usage
 		// This default is probably still too high, and may be adjusted further down in a future release
-		QueueSize: defaultQueueSize,
+		QueueSize: 1_000,
+		Blocking:  false,
 	}
 }
 

exporter/exporterhelper/internal/queue_sender_test.go

@@ -261,7 +261,7 @@ func TestQueuedRetry_QueueMetricsReported(t *testing.T) {
 				require.NoError(t, err)
 				require.NoError(t, be.Start(context.Background(), componenttest.NewNopHost()))
 
-				require.NoError(t, tt.CheckExporterMetricGauge("otelcol_exporter_queue_capacity", int64(defaultQueueSize)))
+				require.NoError(t, tt.CheckExporterMetricGauge("otelcol_exporter_queue_capacity", int64(1000)))
 
 				for i := 0; i < 7; i++ {
 					require.NoError(t, be.Send(context.Background(), newErrorRequest()))
@@ -271,7 +271,7 @@ func TestQueuedRetry_QueueMetricsReported(t *testing.T) {
 
 				assert.NoError(t, be.Shutdown(context.Background()))
 				// metrics should be unregistered at shutdown to prevent memory leak
-				require.Error(t, tt.CheckExporterMetricGauge("otelcol_exporter_queue_capacity", int64(defaultQueueSize)))
+				require.Error(t, tt.CheckExporterMetricGauge("otelcol_exporter_queue_capacity", int64(1000)))
 				require.Error(t, tt.CheckExporterMetricGauge("otelcol_exporter_queue_size", int64(7),
 					attribute.String(DataTypeKey, dataType.String())))
 			}

exporter/exporterqueue/config.go

@@ -20,6 +20,9 @@ type Config struct {
 	NumConsumers int `mapstructure:"num_consumers"`
 	// QueueSize is the maximum number of requests allowed in queue at any given time.
 	QueueSize int `mapstructure:"queue_size"`
+	// Blocking controls the queue behavior when full.
+	// If true it blocks until enough space to add the new request to the queue.
+	Blocking bool `mapstructure:"blocking"`
 }
 
 // NewDefaultConfig returns the default Config.
@@ -30,6 +33,7 @@ func NewDefaultConfig() Config {
 		Enabled:      true,
 		NumConsumers: 10,
 		QueueSize:    1_000,
+		Blocking:     true,
 	}
 }
 

exporter/exporterqueue/queue.go

@@ -69,6 +69,7 @@ func NewMemoryQueueFactory[T any]() Factory[T] {
 		return newBoundedMemoryQueue[T](memoryQueueSettings[T]{
 			sizer:    &requestSizer[T]{},
 			capacity: int64(cfg.QueueSize),
+			blocking: cfg.Blocking,
 		})
 	}
 }
@@ -95,6 +96,7 @@ func NewPersistentQueueFactory[T any](storageID *component.ID, factorySettings P
 		return newPersistentQueue[T](persistentQueueSettings[T]{
 			sizer:       &requestSizer[T]{},
 			capacity:    int64(cfg.QueueSize),
+			blocking:    cfg.Blocking,
 			signal:      set.Signal,
 			storageID:   *storageID,
 			marshaler:   factorySettings.Marshaler,