Move metric No-Op to metric/noop

CHANGELOG.md

@@ -23,6 +23,9 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Both the `Histogram` and `HistogramDataPoint` are redefined with a generic argument of `[N int64 | float64]` in `go.opentelemetry.io/otel/sdk/metric/metricdata`. (#3849)
 - The metric `Export` interface from `go.opentelemetry.io/otel/sdk/metric` accepts a `*ResourceMetrics` instead of `ResourceMetrics`. (#3853)
 - Rename `Asynchronous` to `Observable` in `go.opentelemetry.io/otel/metric/instrument`. (#3892)
+- Move No-Op implementation from `go.opentelemetry.io/otel/metric` into its own package `go.opentelemetry.io/otel/metric`. (#3893)
+  - `NewNoopMeterProvider` is replaced with `noop.NewMeterProvider`
+  - `NewNoopMeter` is replaced with `noop.NewMeterProvider().Meter("")`
 
 ### Removed
 

internal/global/instruments_test.go

@@ -21,6 +21,7 @@ import (
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/instrument"
+	"go.opentelemetry.io/otel/metric/noop"
 )
 
 func testFloat64Race(interact func(context.Context, float64, ...attribute.KeyValue), setDelegate func(metric.Meter)) {
@@ -36,7 +37,7 @@ func testFloat64Race(interact func(context.Context, float64, ...attribute.KeyVal
 		}
 	}()
 
-	setDelegate(metric.NewNoopMeter())
+	setDelegate(noop.NewMeterProvider().Meter(""))
 	close(finish)
 }
 
@@ -53,7 +54,7 @@ func testInt64Race(interact func(context.Context, int64, ...attribute.KeyValue),
 		}
 	}()
 
-	setDelegate(metric.NewNoopMeter())
+	setDelegate(noop.NewMeterProvider().Meter(""))
 	close(finish)
 }
 

internal/global/meter_test.go

@@ -25,6 +25,7 @@ import (
 
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/instrument"
+	"go.opentelemetry.io/otel/metric/noop"
 )
 
 func TestMeterProviderRace(t *testing.T) {
@@ -41,7 +42,7 @@ func TestMeterProviderRace(t *testing.T) {
 		}
 	}()
 
-	mp.setDelegate(metric.NewNoopMeterProvider())
+	mp.setDelegate(noop.NewMeterProvider())
 	close(finish)
 }
 
@@ -84,7 +85,7 @@ func TestMeterRace(t *testing.T) {
 	}()
 
 	wg.Wait()
-	mtr.setDelegate(metric.NewNoopMeterProvider())
+	mtr.setDelegate(noop.NewMeterProvider())
 	close(finish)
 }
 
@@ -113,7 +114,7 @@ func TestUnregisterRace(t *testing.T) {
 	_ = reg.Unregister()
 
 	wg.Wait()
-	mtr.setDelegate(metric.NewNoopMeterProvider())
+	mtr.setDelegate(noop.NewMeterProvider())
 	close(finish)
 }
 

internal/global/state_test.go

@@ -20,6 +20,7 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/noop"
 	"go.opentelemetry.io/otel/propagation"
 	"go.opentelemetry.io/otel/trace"
 )
@@ -152,7 +153,7 @@ func TestSetMeterProvider(t *testing.T) {
 	t.Run("First Set() should replace the delegate", func(t *testing.T) {
 		ResetForTest(t)
 
-		SetMeterProvider(metric.NewNoopMeterProvider())
+		SetMeterProvider(noop.NewMeterProvider())
 
 		_, ok := MeterProvider().(*meterProvider)
 		if ok {
@@ -165,7 +166,7 @@ func TestSetMeterProvider(t *testing.T) {
 
 		mp := MeterProvider()
 
-		SetMeterProvider(metric.NewNoopMeterProvider())
+		SetMeterProvider(noop.NewMeterProvider())
 
 		dmp := mp.(*meterProvider)
 

metric/example_test.go → metric/noop/example_test.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package metric_test
+package noop_test
 
 import (
 	"context"
@@ -23,12 +23,13 @@ import (
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/instrument"
+	"go.opentelemetry.io/otel/metric/noop"
 )
 
 //nolint:govet // Meter doesn't register for go vet
 func ExampleMeter_synchronous() {
 	// In a library or program this would be provided by otel.GetMeterProvider().
-	meterProvider := metric.NewNoopMeterProvider()
+	meterProvider := noop.NewMeterProvider()
 
 	workDuration, err := meterProvider.Meter("go.opentelemetry.io/otel/metric#SyncExample").Int64Histogram(
 		"workDuration",
@@ -48,7 +49,7 @@ func ExampleMeter_synchronous() {
 //nolint:govet // Meter doesn't register for go vet
 func ExampleMeter_asynchronous_single() {
 	// In a library or program this would be provided by otel.GetMeterProvider().
-	meterProvider := metric.NewNoopMeterProvider()
+	meterProvider := noop.NewMeterProvider()
 	meter := meterProvider.Meter("go.opentelemetry.io/otel/metric#AsyncExample")
 
 	_, err := meter.Int64ObservableGauge(
@@ -80,7 +81,7 @@ func ExampleMeter_asynchronous_single() {
 
 //nolint:govet // Meter doesn't register for go vet
 func ExampleMeter_asynchronous_multiple() {
-	meterProvider := metric.NewNoopMeterProvider()
+	meterProvider := noop.NewMeterProvider()
 	meter := meterProvider.Meter("go.opentelemetry.io/otel/metric#MultiAsyncExample")
 
 	// This is just a sample of memory stats to record from the Memstats