[exporter/elasticsearch] set the default User-Agent header in the out…

…going HTTP requests (open-telemetry#29911)

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

**Link to tracking Issue:** close
open-telemetry#29898

**Testing:** <Describe what testing was performed and which tests were
added.>

**Documentation:** <Describe the documentation added.>

---------

Signed-off-by: Jared Tan <jian.tan@daocloud.io>

.chloggen/elasticsearchexporter-set-the-User-Agent-header-in-the-outgoing-HTTP-requests.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: exporter/elasticsearch
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: set the User-Agent header in the outgoing HTTP requests.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [29898]
+
+# (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: []

exporter/elasticsearchexporter/factory.go

@@ -8,6 +8,7 @@ package elasticsearchexporter // import "github.com/open-telemetry/opentelemetry
 import (
 	"context"
 	"fmt"
+	"runtime"
 	"time"
 
 	"go.opentelemetry.io/collector/component"
@@ -21,6 +22,7 @@ const (
 	// The value of "type" key in configuration.
 	defaultLogsIndex   = "logs-generic-default"
 	defaultTracesIndex = "traces-generic-default"
+	userAgentHeaderKey = "User-Agent"
 )
 
 // NewFactory creates a factory for Elastic exporter.
@@ -76,6 +78,8 @@ func createLogsExporter(
 		set.Logger.Warn("index option are deprecated and replaced with logs_index and traces_index.")
 	}
 
+	setDefaultUserAgentHeader(cf, set.BuildInfo)
+
 	logsExporter, err := newLogsExporter(set.Logger, cf)
 	if err != nil {
 		return nil, fmt.Errorf("cannot configure Elasticsearch logsExporter: %w", err)
@@ -96,6 +100,9 @@ func createTracesExporter(ctx context.Context,
 	cfg component.Config) (exporter.Traces, error) {
 
 	cf := cfg.(*Config)
+
+	setDefaultUserAgentHeader(cf, set.BuildInfo)
+
 	tracesExporter, err := newTracesExporter(set.Logger, cf)
 	if err != nil {
 		return nil, fmt.Errorf("cannot configure Elasticsearch tracesExporter: %w", err)
@@ -108,3 +115,14 @@ func createTracesExporter(ctx context.Context,
 		exporterhelper.WithShutdown(tracesExporter.Shutdown),
 		exporterhelper.WithQueue(cf.QueueSettings))
 }
+
+// set default User-Agent header with BuildInfo if User-Agent is empty
+func setDefaultUserAgentHeader(cf *Config, info component.BuildInfo) {
+	if _, found := cf.Headers[userAgentHeaderKey]; found {
+		return
+	}
+	if cf.Headers == nil {
+		cf.Headers = make(map[string]string)
+	}
+	cf.Headers[userAgentHeaderKey] = fmt.Sprintf("%s/%s (%s/%s)", info.Description, info.Version, runtime.GOOS, runtime.GOARCH)
+}

exporter/elasticsearchexporter/factory_test.go

@@ -5,10 +5,12 @@ package elasticsearchexporter
 
 import (
 	"context"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/component/componenttest"
 	"go.opentelemetry.io/collector/exporter/exportertest"
 )
@@ -66,3 +68,24 @@ func TestFactory_CreateLogsAndTracesExporterWithDeprecatedIndexOption(t *testing
 	require.NotNil(t, tracesExporter)
 	require.NoError(t, tracesExporter.Shutdown(context.TODO()))
 }
+
+func TestSetDefaultUserAgentHeader(t *testing.T) {
+	t.Run("insert default user agent header into empty", func(t *testing.T) {
+		factory := NewFactory()
+		cfg := factory.CreateDefaultConfig().(*Config)
+		setDefaultUserAgentHeader(cfg, component.BuildInfo{Description: "mock OpenTelemetry Collector", Version: "latest"})
+		assert.Equal(t, len(cfg.Headers), 1)
+		assert.Equal(t, strings.Contains(cfg.Headers[userAgentHeaderKey], "OpenTelemetry Collector"), true)
+	})
+
+	t.Run("ignore user agent header if configured", func(t *testing.T) {
+		factory := NewFactory()
+		cfg := factory.CreateDefaultConfig().(*Config)
+		cfg.Headers = map[string]string{
+			userAgentHeaderKey: "mock user agent header",
+		}
+		setDefaultUserAgentHeader(cfg, component.BuildInfo{Description: "mock OpenTelemetry Collector", Version: "latest"})
+		assert.Equal(t, len(cfg.Headers), 1)
+		assert.Equal(t, cfg.Headers[userAgentHeaderKey], "mock user agent header")
+	})
+}