Support a single Resource per MeterProvider in the SDK

CHANGELOG.md

@@ -12,6 +12,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Changed
 
+- The Metrics SDK export record no longer contains a Resource pointer, the SDK `Export()` function for push-based exporters now takes a single Resource argument, pull-based exporters use `controller.Resource()`. (#2120)
+
 ### Deprecated
 
 ### Removed
@@ -20,6 +22,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Fixed
 
+- The Metric SDK controller constructor does not automatically merge `resource.Environment()`. Multiple calls to `WithResource()` are handled correctly, and when no resources are provided `resource.Default()` is used. (#2120)
+
 ### Security
 
 ## [v1.0.0-RC2] - 2021-07-26

bridge/opencensus/exporter.go

@@ -50,7 +50,11 @@ type exporter struct {
 
 // ExportMetrics implements the OpenCensus metric Exporter interface
 func (e *exporter) ExportMetrics(ctx context.Context, metrics []*metricdata.Metric) error {
-	return e.base.Export(ctx, &checkpointSet{metrics: metrics})
+	res := resource.Empty()
+	if len(metrics) != 0 {
+		res = convertResource(metrics[0].Resource)
+	}
+	return e.base.Export(ctx, res, &checkpointSet{metrics: metrics})
 }
 
 type checkpointSet struct {
@@ -68,7 +72,6 @@ func (d *checkpointSet) ForEach(exporter export.ExportKindSelector, f func(expor
 			otel.Handle(err)
 			continue
 		}
-		res := convertResource(m.Resource)
 		for _, ts := range m.TimeSeries {
 			if len(ts.Points) == 0 {
 				continue
@@ -86,7 +89,6 @@ func (d *checkpointSet) ForEach(exporter export.ExportKindSelector, f func(expor
 			if err := f(export.NewRecord(
 				&descriptor,
 				&ls,
-				res,
 				agg,
 				ts.StartTime,
 				agg.end(),
@@ -118,6 +120,7 @@ func convertLabels(keys []metricdata.LabelKey, values []metricdata.LabelValue) (
 }
 
 // convertResource converts an OpenCensus Resource to an OpenTelemetry Resource
+// Note: the ocresource.Resource Type field is not used.
 func convertResource(res *ocresource.Resource) *resource.Resource {
 	labels := []attribute.KeyValue{}
 	if res == nil {

bridge/opencensus/exporter_test.go

@@ -38,12 +38,14 @@ import (
 
 type fakeExporter struct {
 	export.Exporter
-	records []export.Record
-	err     error
+	records  []export.Record
+	resource *resource.Resource
+	err      error
 }
 
-func (f *fakeExporter) Export(ctx context.Context, cps exportmetric.CheckpointSet) error {
+func (f *fakeExporter) Export(ctx context.Context, res *resource.Resource, cps exportmetric.CheckpointSet) error {
 	return cps.ForEach(f, func(record exportmetric.Record) error {
+		f.resource = res
 		f.records = append(f.records, record)
 		return f.err
 	})
@@ -81,6 +83,7 @@ func TestExportMetrics(t *testing.T) {
 		input                []*metricdata.Metric
 		exportErr            error
 		expected             []export.Record
+		expectedResource     *resource.Resource
 		expectedHandledError error
 	}{
 		{
@@ -141,6 +144,12 @@ func TestExportMetrics(t *testing.T) {
 			desc: "success",
 			input: []*metricdata.Metric{
 				{
+					Resource: &ocresource.Resource{
+						Labels: map[string]string{
+							"R1": "V1",
+							"R2": "V2",
+						},
+					},
 					TimeSeries: []*metricdata.TimeSeries{
 						{
 							StartTime: now,
@@ -151,11 +160,14 @@ func TestExportMetrics(t *testing.T) {
 					},
 				},
 			},
+			expectedResource: resource.NewSchemaless(
+				attribute.String("R1", "V1"),
+				attribute.String("R2", "V2"),
+			),
 			expected: []export.Record{
 				export.NewRecord(
 					&basicDesc,
 					attribute.EmptySet(),
-					resource.NewSchemaless(),
 					&ocExactAggregator{
 						points: []aggregation.Point{
 							{
@@ -187,7 +199,6 @@ func TestExportMetrics(t *testing.T) {
 				export.NewRecord(
 					&basicDesc,
 					attribute.EmptySet(),
-					resource.NewSchemaless(),
 					&ocExactAggregator{
 						points: []aggregation.Point{
 							{
@@ -222,7 +233,6 @@ func TestExportMetrics(t *testing.T) {
 				export.NewRecord(
 					&basicDesc,
 					attribute.EmptySet(),
-					resource.NewSchemaless(),
 					&ocExactAggregator{
 						points: []aggregation.Point{
 							{
@@ -254,16 +264,16 @@ func TestExportMetrics(t *testing.T) {
 			if len(tc.expected) != len(output) {
 				t.Fatalf("ExportMetrics(%+v) = %d records, want %d records", tc.input, len(output), len(tc.expected))
 			}
+			if fakeExporter.resource.String() != tc.expectedResource.String() {
+				t.Errorf("ExportMetrics(%+v)[i].Resource() = %+v, want %+v", tc.input, fakeExporter.resource.String(), tc.expectedResource.String())
+			}
 			for i, expected := range tc.expected {
 				if output[i].StartTime() != expected.StartTime() {
 					t.Errorf("ExportMetrics(%+v)[i].StartTime() = %+v, want %+v", tc.input, output[i].StartTime(), expected.StartTime())
 				}
 				if output[i].EndTime() != expected.EndTime() {
 					t.Errorf("ExportMetrics(%+v)[i].EndTime() = %+v, want %+v", tc.input, output[i].EndTime(), expected.EndTime())
 				}
-				if output[i].Resource().String() != expected.Resource().String() {
-					t.Errorf("ExportMetrics(%+v)[i].Resource() = %+v, want %+v", tc.input, output[i].Resource().String(), expected.Resource().String())
-				}
 				if output[i].Descriptor().Name() != expected.Descriptor().Name() {
 					t.Errorf("ExportMetrics(%+v)[i].Descriptor() = %+v, want %+v", tc.input, output[i].Descriptor().Name(), expected.Descriptor().Name())
 				}

exporters/otlp/otlpmetric/exporter.go

@@ -23,6 +23,7 @@ import (
 	"go.opentelemetry.io/otel/metric"
 	metricsdk "go.opentelemetry.io/otel/sdk/export/metric"
 	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/resource"
 )
 
 var (
@@ -42,8 +43,8 @@ type Exporter struct {
 }
 
 // Export exports a batch of metrics.
-func (e *Exporter) Export(ctx context.Context, checkpointSet metricsdk.CheckpointSet) error {
-	rms, err := metrictransform.CheckpointSet(ctx, e, checkpointSet, 1)
+func (e *Exporter) Export(ctx context.Context, res *resource.Resource, checkpointSet metricsdk.CheckpointSet) error {
+	rms, err := metrictransform.CheckpointSet(ctx, e, res, checkpointSet, 1)
 	if err != nil {
 		return err
 	}