[service] Allow users to disable the tracer provider via the feature …

…gate `service.noopTracerProvider` (#10859)

Previously the service was returning an instance of a SDK tracer
provider regardless of whether there were any processors configured
causing resources to be consumed unnecessarily.

Fixes #10858

---------

Signed-off-by: Alex Boten <[email protected]>

.chloggen/codeboten_disable-tracer-without-config.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: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: service
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Allow users to disable the tracer provider via the feature gate `service.noopTracerProvider`"
+
+# One or more tracking issues or pull requests related to the change
+issues: [10858]
+
+# (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 service is returning an instance of a SDK tracer provider regardless of whether there were any processors configured causing resources to be consumed unnecessarily.
+
+# 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: []

internal/globalgates/globalgates.go

@@ -24,3 +24,8 @@ var DisableOpenCensusBridge = featuregate.GlobalRegistry().MustRegister("service
 	featuregate.WithRegisterFromVersion("v0.105.0"),
 	featuregate.WithRegisterToVersion("v0.109.0"),
 	featuregate.WithRegisterDescription("`Disables the OpenCensus bridge meaning any component still using the OpenCensus SDK will no longer be able to produce telemetry."))
+
+var NoopTracerProvider = featuregate.GlobalRegistry().MustRegister("service.noopTracerProvider",
+	featuregate.StageAlpha,
+	featuregate.WithRegisterFromVersion("v0.107.0"),
+	featuregate.WithRegisterDescription("Sets a Noop OpenTelemetry TracerProvider to reduce memory allocations. This featuregate is incompatible with the zPages extension."))

service/go.mod

@@ -21,6 +21,7 @@ require (
 	go.opentelemetry.io/collector/extension v0.106.1
 	go.opentelemetry.io/collector/extension/zpagesextension v0.106.1
 	go.opentelemetry.io/collector/featuregate v1.12.0
+	go.opentelemetry.io/collector/internal/globalgates v0.106.1
 	go.opentelemetry.io/collector/pdata v1.12.0
 	go.opentelemetry.io/collector/pdata/testdata v0.106.1
 	go.opentelemetry.io/collector/processor v0.106.1
@@ -86,7 +87,6 @@ require (
 	go.opentelemetry.io/collector/config/internal v0.106.1 // indirect
 	go.opentelemetry.io/collector/consumer/consumerprofiles v0.106.1 // indirect
 	go.opentelemetry.io/collector/extension/auth v0.106.1 // indirect
-	go.opentelemetry.io/collector/internal/globalgates v0.106.1 // indirect
 	go.opentelemetry.io/collector/pdata/pprofile v0.106.1 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.53.0 // indirect
 	go.opentelemetry.io/contrib/zpages v0.53.0 // indirect

service/telemetry/tracer.go

@@ -13,6 +13,9 @@ import (
 	"go.opentelemetry.io/otel/propagation"
 	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
 	"go.opentelemetry.io/otel/trace"
+	"go.opentelemetry.io/otel/trace/noop"
+
+	"go.opentelemetry.io/collector/internal/globalgates"
 )
 
 const (
@@ -45,6 +48,9 @@ func attributes(set Settings, cfg Config) map[string]interface{} {
 
 // New creates a new Telemetry from Config.
 func newTracerProvider(ctx context.Context, set Settings, cfg Config) (trace.TracerProvider, error) {
+	if globalgates.NoopTracerProvider.IsEnabled() {
+		return noop.NewTracerProvider(), nil
+	}
 	sch := semconv.SchemaURL
 	res := config.Resource{
 		SchemaUrl:  &sch,

service/telemetry/tracer_test.go

@@ -4,11 +4,16 @@
 package telemetry // import "go.opentelemetry.io/collector/service/telemetry"
 
 import (
+	"context"
 	"testing"
 
 	"github.com/stretchr/testify/require"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+	"go.opentelemetry.io/otel/trace/noop"
 
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/featuregate"
+	"go.opentelemetry.io/collector/internal/globalgates"
 	"go.opentelemetry.io/collector/service/telemetry/internal"
 )
 
@@ -56,6 +61,38 @@ func TestAttributes(t *testing.T) {
 	}
 }
 
+func TestNewTracerProvider(t *testing.T) {
+	tests := []struct {
+		name               string
+		wantTracerProvider any
+		noopTracer         bool
+	}{
+		{
+			name:               "noop tracer provider",
+			noopTracer:         true,
+			wantTracerProvider: noop.TracerProvider{},
+		},
+		{
+			name:               "tracer provider",
+			wantTracerProvider: &sdktrace.TracerProvider{},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			previousValue := globalgates.NoopTracerProvider.IsEnabled()
+			err := featuregate.GlobalRegistry().Set(globalgates.NoopTracerProvider.ID(), tt.noopTracer)
+			require.NoError(t, err)
+			defer func() {
+				err = featuregate.GlobalRegistry().Set(globalgates.NoopTracerProvider.ID(), previousValue)
+				require.NoError(t, err)
+			}()
+			provider, err := newTracerProvider(context.TODO(), internal.Settings{}, Config{})
+			require.NoError(t, err)
+			require.IsType(t, tt.wantTracerProvider, provider)
+		})
+	}
+}
+
 func ptr[T any](v T) *T {
 	return &v
 }