[otelarrowexporter] Support the new experimental batcher (open-telemetry#34802)

**Description:** Add exportbatcher.BatcherConfig to OTel-Arrow exporter.
Follows
open-telemetry/opentelemetry-collector#10846 as
we intend to maintain parity between OTLP/gRPC and OTel-Arrow exporters.

**Link to tracking Issue:** 

**Testing:** ✅ 

**Documentation:** README updated with reference to new batcher and
[concurrent batch
processor](https://github.com/open-telemetry/otel-arrow/tree/main/collector/processor/concurrentbatchprocessor)
in the otel-arrow repo.

---------

Co-authored-by: Matthew Wear <matthew.wear@gmail.com>

Author: jmacd

.chloggen/otelarrow-batcher.yaml

@@ -0,0 +1,27 @@
+# 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. filelogreceiver)
+component: otelarrowexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add BatcherConfig field following similar in OTLP exporter.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [34802]
+
+# (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 your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# 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/otelarrowexporter/README.md

@@ -241,3 +241,47 @@ exporters:
       zstd:
         level: 1       # 1 is the "fastest" compression level
 ```
+
+### Batching Configuration
+
+This exporter includes a new, experimental `batcher` configuration for
+batching in the `exporterhelper` module, but this mode is disabled by
+default.  This batching support works when combined with
+`queue_sender` functionality.
+
+```
+exporters:
+  otelarrow:
+    batcher:
+	  enabled: true
+    sending_queue:
+      enabled: true
+      storage: file_storage/otc
+extensions:
+  file_storage/otc:
+    directory: /var/lib/storage/otc
+```
+
+The built-in batcher is only recommended with a persistent queue,
+otherwise it cannot provide back-pressure to the caller.  If building
+a custom build of the OpenTelemetry Collector, we recommend using the
+[Concurrent Batch
+Processor](https://github.com/open-telemetry/otel-arrow/blob/main/collector/processor/concurrentbatchprocessor/README.md)
+to provide simultaneous back-pressure, concurrency, and batching
+functionality.  See [more discussion on this
+issue](https://github.com/open-telemetry/opentelemetry-collector/issues/10368).
+
+```
+exporters:
+  otelarrow:
+    batcher:
+	  enabled: false
+    sending_queue:
+      enabled: false
+processors:
+  concurrentbatch:
+    send_batch_max_size: 1500
+    send_batch_size: 1000
+    timeout: 1s
+    max_in_flight_size_mib: 128
+```

exporter/otelarrowexporter/config.go

@@ -12,6 +12,7 @@ import (
 	"go.opentelemetry.io/collector/config/configcompression"
 	"go.opentelemetry.io/collector/config/configgrpc"
 	"go.opentelemetry.io/collector/config/configretry"
+	"go.opentelemetry.io/collector/exporter/exporterbatcher"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
 	"google.golang.org/grpc"
 
@@ -32,6 +33,10 @@ type Config struct {
 
 	configgrpc.ClientConfig `mapstructure:",squash"` // squash ensures fields are correctly decoded in embedded struct.
 
+	// Experimental: This configuration 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
+	BatcherConfig exporterbatcher.Config `mapstructure:"batcher"`
+
 	// Arrow includes settings specific to OTel Arrow.
 	Arrow ArrowConfig `mapstructure:"arrow"`
 

exporter/otelarrowexporter/config_test.go

@@ -20,6 +20,7 @@ import (
 	"go.opentelemetry.io/collector/config/configretry"
 	"go.opentelemetry.io/collector/config/configtls"
 	"go.opentelemetry.io/collector/confmap/confmaptest"
+	"go.opentelemetry.io/collector/exporter/exporterbatcher"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/otelarrowexporter/internal/arrow"
@@ -84,6 +85,16 @@ func TestUnmarshalConfig(t *testing.T) {
 				BalancerName:    "experimental",
 				Auth:            &configauth.Authentication{AuthenticatorID: component.NewID(component.MustNewType("nop"))},
 			},
+			BatcherConfig: exporterbatcher.Config{
+				Enabled:      true,
+				FlushTimeout: 200 * time.Millisecond,
+				MinSizeConfig: exporterbatcher.MinSizeConfig{
+					MinSizeItems: 1000,
+				},
+				MaxSizeConfig: exporterbatcher.MaxSizeConfig{
+					MaxSizeItems: 10000,
+				},
+			},
 			Arrow: ArrowConfig{
 				NumStreams:         2,
 				MaxStreamLifetime:  2 * time.Hour,

exporter/otelarrowexporter/factory.go

@@ -16,6 +16,7 @@ import (
 	"go.opentelemetry.io/collector/config/configretry"
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/exporter"
+	"go.opentelemetry.io/collector/exporter/exporterbatcher"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
 	"google.golang.org/grpc"
 
@@ -37,10 +38,14 @@ func NewFactory() exporter.Factory {
 }
 
 func createDefaultConfig() component.Config {
+	batcherCfg := exporterbatcher.NewDefaultConfig()
+	batcherCfg.Enabled = false
+
 	return &Config{
 		TimeoutSettings: exporterhelper.NewDefaultTimeoutSettings(),
 		RetryConfig:     configretry.NewDefaultBackOffConfig(),
 		QueueSettings:   exporterhelper.NewDefaultQueueSettings(),
+		BatcherConfig:   batcherCfg,
 		ClientConfig: configgrpc.ClientConfig{
 			Headers: map[string]configopaque.String{},
 			// Default to zstd compression
@@ -74,6 +79,7 @@ func (exp *baseExporter) helperOptions() []exporterhelper.Option {
 		exporterhelper.WithRetry(exp.config.RetryConfig),
 		exporterhelper.WithQueue(exp.config.QueueSettings),
 		exporterhelper.WithStart(exp.start),
+		exporterhelper.WithBatcher(exp.config.BatcherConfig),
 		exporterhelper.WithShutdown(exp.shutdown),
 	}
 }

exporter/otelarrowexporter/testdata/config.yaml

@@ -25,6 +25,11 @@ keepalive:
   timeout: 30s
   permit_without_stream: true
 balancer_name: "experimental"
+batcher:
+  enabled: true
+  flush_timeout: 200ms
+  min_size_items: 1000
+  max_size_items: 10000
 arrow:
   num_streams: 2
   disabled: false