Move metric-related public API out of otel/ pkg

Move GetMeterProvider, Meter and SetMeterProvider to new package
otel/metric/global in the otel/metric module.

This will allow otel/ module to be released as v1.0.

CHANGELOG.md

@@ -14,6 +14,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Reverse order in which `Resource` attributes are merged, per change in spec. (#1501)
 - Add tooling to maintain "replace" directives in go.mod files automatically.
 - Create new modules: otel/metric, otel/trace, otel/oteltest, otel/sdk/export/metric, otel/sdk/metric
+- Move metric-related public APIs from otel to otel/metric/global.
 
 ## [0.16.0] - 2020-01-13
 

example/otel-collector/main.go

@@ -30,6 +30,7 @@ import (
 	"go.opentelemetry.io/otel/exporters/otlp/otlpgrpc"
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/global"
 	"go.opentelemetry.io/otel/propagation"
 	controller "go.opentelemetry.io/otel/sdk/metric/controller/basic"
 	processor "go.opentelemetry.io/otel/sdk/metric/processor/basic"
@@ -85,7 +86,7 @@ func initProvider() func() {
 	// set global propagator to tracecontext (the default is no-op).
 	otel.SetTextMapPropagator(propagation.TraceContext{})
 	otel.SetTracerProvider(tracerProvider)
-	otel.SetMeterProvider(cont.MeterProvider())
+	global.SetMeterProvider(cont.MeterProvider())
 	handleErr(cont.Start(context.Background()), "failed to start controller")
 
 	return func() {
@@ -104,7 +105,7 @@ func main() {
 	defer shutdown()
 
 	tracer := otel.Tracer("test-tracer")
-	meter := otel.Meter("test-meter")
+	meter := global.Meter("test-meter")
 
 	// labels represent additional key-value descriptors that can be bound to a
 	// metric observer or recorder.

example/prom-collector/main.go

@@ -23,12 +23,12 @@ import (
 
 	"google.golang.org/grpc"
 
-	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/exporters/metric/prometheus"
 	"go.opentelemetry.io/otel/exporters/otlp"
 	"go.opentelemetry.io/otel/exporters/otlp/otlpgrpc"
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/global"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/histogram"
 	controller "go.opentelemetry.io/otel/sdk/metric/controller/basic"
 	processor "go.opentelemetry.io/otel/sdk/metric/processor/basic"
@@ -85,7 +85,7 @@ func initMeter() {
 		log.Fatal(http.ListenAndServe(":17000", nil))
 	}()
 
-	otel.SetMeterProvider(cont.MeterProvider())
+	global.SetMeterProvider(cont.MeterProvider())
 
 	log.Println("Prometheus server running on :17000")
 	log.Println("Exporting OTLP to :30080")
@@ -98,7 +98,7 @@ func main() {
 		label.String("label1", "value1"),
 	}
 
-	meter := otel.Meter("ex.com/prom-collector")
+	meter := global.Meter("ex.com/prom-collector")
 	_ = metric.Must(meter).NewFloat64ValueObserver(
 		"randval",
 		func(_ context.Context, result metric.Float64ObserverResult) {

example/prometheus/main.go

@@ -22,10 +22,10 @@ import (
 	"sync"
 	"time"
 
-	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/exporters/metric/prometheus"
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/global"
 )
 
 var (
@@ -48,7 +48,7 @@ func initMeter() {
 func main() {
 	initMeter()
 
-	meter := otel.Meter("ex.com/basic")
+	meter := global.Meter("ex.com/basic")
 	observerLock := new(sync.RWMutex)
 	observerValueToReport := new(float64)
 	observerLabelsToReport := new([]label.KeyValue)

exporters/metric/prometheus/prometheus.go

@@ -29,6 +29,7 @@ import (
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/global"
 	"go.opentelemetry.io/otel/metric/number"
 	export "go.opentelemetry.io/otel/sdk/export/metric"
 	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
@@ -142,7 +143,7 @@ func InstallNewPipeline(config Config, options ...controller.Option) (*Exporter,
 	if err != nil {
 		return nil, err
 	}
-	otel.SetMeterProvider(exp.MeterProvider())
+	global.SetMeterProvider(exp.MeterProvider())
 	return exp, nil
 }
 

exporters/otlp/otlpgrpc/example_test.go

@@ -26,6 +26,7 @@ import (
 	"go.opentelemetry.io/otel/exporters/otlp"
 	"go.opentelemetry.io/otel/exporters/otlp/otlpgrpc"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/global"
 	controller "go.opentelemetry.io/otel/sdk/metric/controller/basic"
 	processor "go.opentelemetry.io/otel/sdk/metric/processor/basic"
 	"go.opentelemetry.io/otel/sdk/metric/selector/simple"
@@ -187,7 +188,7 @@ func Example_withDifferentSignalCollectors() {
 		controller.WithPusher(exp),
 		controller.WithCollectPeriod(2*time.Second),
 	)
-	otel.SetMeterProvider(pusher.MeterProvider())
+	global.SetMeterProvider(pusher.MeterProvider())
 
 	if err := pusher.Start(ctx); err != nil {
 		log.Fatalf("could not start metric controoler: %v", err)
@@ -202,7 +203,7 @@ func Example_withDifferentSignalCollectors() {
 	}()
 
 	tracer := otel.Tracer("test-tracer")
-	meter := otel.Meter("test-meter")
+	meter := global.Meter("test-meter")
 
 	// Recorder metric example
 	counter := metric.Must(meter).

exporters/stdout/example_test.go

@@ -22,6 +22,7 @@ import (
 	"go.opentelemetry.io/otel/exporters/stdout"
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/global"
 	"go.opentelemetry.io/otel/trace"
 )
 
@@ -36,7 +37,7 @@ var (
 		trace.WithInstrumentationVersion(instrumentationVersion),
 	)
 
-	meter = otel.GetMeterProvider().Meter(
+	meter = global.GetMeterProvider().Meter(
 		instrumentationName,
 		metric.WithInstrumentationVersion(instrumentationVersion),
 	)

exporters/stdout/exporter.go

@@ -18,6 +18,7 @@ import (
 	"context"
 
 	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/metric/global"
 	"go.opentelemetry.io/otel/sdk/export/metric"
 	exporttrace "go.opentelemetry.io/otel/sdk/export/trace"
 	controller "go.opentelemetry.io/otel/sdk/metric/controller/basic"
@@ -92,6 +93,6 @@ func InstallNewPipeline(exportOpts []Option, pushOpts []controller.Option) (*con
 		return controller, err
 	}
 	otel.SetTracerProvider(tracerProvider)
-	otel.SetMeterProvider(controller.MeterProvider())
+	global.SetMeterProvider(controller.MeterProvider())
 	return controller, err
 }

internal/global/benchmark_test.go

@@ -21,6 +21,7 @@ import (
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/internal/global"
 	"go.opentelemetry.io/otel/label"
+	metricglobal "go.opentelemetry.io/otel/metric/global"
 )
 
 func BenchmarkGlobalInt64CounterAddNoSDK(b *testing.B) {
@@ -29,7 +30,7 @@ func BenchmarkGlobalInt64CounterAddNoSDK(b *testing.B) {
 	// global no-op system against a registered SDK.
 	global.ResetForTest()
 	ctx := context.Background()
-	sdk := otel.Meter("test")
+	sdk := metricglobal.Meter("test")
 	labs := []label.KeyValue{label.String("A", "B")}
 	cnt := Must(sdk).NewInt64Counter("int64.counter")
 

internal/global/meter_test.go

@@ -21,10 +21,10 @@ import (
 
 	"github.com/stretchr/testify/require"
 
-	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/internal/global"
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	metricglobal "go.opentelemetry.io/otel/metric/global"
 	"go.opentelemetry.io/otel/metric/number"
 	"go.opentelemetry.io/otel/oteltest"
 )
@@ -38,8 +38,8 @@ func TestDirect(t *testing.T) {
 	global.ResetForTest()
 
 	ctx := context.Background()
-	meter1 := otel.Meter("test1", metric.WithInstrumentationVersion("semver:v1.0.0"))
-	meter2 := otel.Meter("test2")
+	meter1 := metricglobal.Meter("test1", metric.WithInstrumentationVersion("semver:v1.0.0"))
+	meter2 := metricglobal.Meter("test2")
 	labels1 := []label.KeyValue{label.String("A", "B")}
 	labels2 := []label.KeyValue{label.String("C", "D")}
 	labels3 := []label.KeyValue{label.String("E", "F")}
@@ -67,7 +67,7 @@ func TestDirect(t *testing.T) {
 	second.Record(ctx, 2, labels3...)
 
 	mock, provider := oteltest.NewMeterProvider()
-	otel.SetMeterProvider(provider)
+	metricglobal.SetMeterProvider(provider)
 
 	counter.Add(ctx, 1, labels1...)
 	valuerecorder.Record(ctx, 3, labels1...)
@@ -138,7 +138,7 @@ func TestBound(t *testing.T) {
 	// Note: this test uses opposite Float64/Int64 number kinds
 	// vs. the above, to cover all the instruments.
 	ctx := context.Background()
-	glob := otel.Meter("test")
+	glob := metricglobal.Meter("test")
 	labels1 := []label.KeyValue{label.String("A", "B")}
 
 	counter := Must(glob).NewFloat64Counter("test.counter")
@@ -152,7 +152,7 @@ func TestBound(t *testing.T) {
 	boundM.Record(ctx, 2)
 
 	mock, provider := oteltest.NewMeterProvider()
-	otel.SetMeterProvider(provider)
+	metricglobal.SetMeterProvider(provider)
 
 	boundC.Add(ctx, 1)
 	boundM.Record(ctx, 3)
@@ -182,7 +182,7 @@ func TestUnbind(t *testing.T) {
 	// Tests Unbind with SDK never installed.
 	global.ResetForTest()
 
-	glob := otel.Meter("test")
+	glob := metricglobal.Meter("test")
 	labels1 := []label.KeyValue{label.String("A", "B")}
 
 	counter := Must(glob).NewFloat64Counter("test.counter")
@@ -201,10 +201,10 @@ func TestUnbindThenRecordOne(t *testing.T) {
 	ctx := context.Background()
 	mock, provider := oteltest.NewMeterProvider()
 
-	meter := otel.Meter("test")
+	meter := metricglobal.Meter("test")
 	counter := Must(meter).NewInt64Counter("test.counter")
 	boundC := counter.Bind()
-	otel.SetMeterProvider(provider)
+	metricglobal.SetMeterProvider(provider)
 	boundC.Unbind()
 
 	require.NotPanics(t, func() {
@@ -233,7 +233,7 @@ func TestErrorInDeferredConstructor(t *testing.T) {
 	global.ResetForTest()
 
 	ctx := context.Background()
-	meter := otel.GetMeterProvider().Meter("builtin")
+	meter := metricglobal.GetMeterProvider().Meter("builtin")
 
 	c1 := Must(meter).NewInt64Counter("test")
 	c2 := Must(meter).NewInt64Counter("test")
@@ -242,7 +242,7 @@ func TestErrorInDeferredConstructor(t *testing.T) {
 	sdk := &meterProviderWithConstructorError{provider}
 
 	require.Panics(t, func() {
-		otel.SetMeterProvider(sdk)
+		metricglobal.SetMeterProvider(sdk)
 	})
 
 	c1.Add(ctx, 1)
@@ -256,7 +256,7 @@ func TestImplementationIndirection(t *testing.T) {
 	// returns the implementation interface not the global, after
 	// registered.
 
-	meter1 := otel.Meter("test1")
+	meter1 := metricglobal.Meter("test1")
 
 	// Sync: no SDK yet
 	counter := Must(meter1).NewInt64Counter("interface.counter")
@@ -281,7 +281,7 @@ func TestImplementationIndirection(t *testing.T) {
 
 	// Register the SDK
 	_, provider := oteltest.NewMeterProvider()
-	otel.SetMeterProvider(provider)
+	metricglobal.SetMeterProvider(provider)
 
 	// Repeat the above tests
 
@@ -303,14 +303,14 @@ func TestImplementationIndirection(t *testing.T) {
 func TestRecordBatchMock(t *testing.T) {
 	global.ResetForTest()
 
-	meter := otel.GetMeterProvider().Meter("builtin")
+	meter := metricglobal.GetMeterProvider().Meter("builtin")
 
 	counter := Must(meter).NewInt64Counter("test.counter")
 
 	meter.RecordBatch(context.Background(), nil, counter.Measurement(1))
 
 	mock, provider := oteltest.NewMeterProvider()
-	otel.SetMeterProvider(provider)
+	metricglobal.SetMeterProvider(provider)
 
 	meter.RecordBatch(context.Background(), nil, counter.Measurement(1))
 

metric.go → metric/global/metric.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package otel // import "go.opentelemetry.io/otel"
+package global // import "go.opentelemetry.io/otel/metric/global"
 
 import (
 	"go.opentelemetry.io/otel/internal/global"

metric_test.go → metric/global/metric_test.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package otel
+package global
 
 import (
 	"testing"

sdk/metric/benchmark_test.go

@@ -20,9 +20,9 @@ import (
 	"math/rand"
 	"testing"
 
-	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/global"
 	export "go.opentelemetry.io/otel/sdk/export/metric"
 	sdk "go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/metric/processor/processortest"
@@ -214,8 +214,8 @@ func BenchmarkGlobalInt64CounterAddWithSDK(b *testing.B) {
 	ctx := context.Background()
 	fix := newFixture(b)
 
-	sdk := otel.Meter("test")
-	otel.SetMeterProvider(fix)
+	sdk := global.Meter("test")
+	global.SetMeterProvider(fix)
 
 	labs := []label.KeyValue{label.String("A", "B")}
 	cnt := Must(sdk).NewInt64Counter("int64.sum")