Improve detail in stdout exporter (#436)

* Switch stdout exporter to use ungrouped batcher

* Add unspecified keys to name without equals signs

* Fix tests for stdout exporter

* Add test for unspecified keys

* Move test to stdout_test.go

api/global/internal/meter_test.go

@@ -222,6 +222,6 @@ func TestDefaultSDK(t *testing.T) {
 	pusher.Stop()
 	out.Close()
 
-	require.Equal(t, `{"updates":[{"name":"test.builtin","sum":1}]}
+	require.Equal(t, `{"updates":[{"name":"test.builtin{A=B}","sum":1}]}
 `, <-ch)
 }

exporter/metric/stdout/stdout.go

@@ -23,12 +23,12 @@ import (
 	"strings"
 	"time"
 
+	"go.opentelemetry.io/otel/api/core"
 	"go.opentelemetry.io/otel/api/global"
 
 	export "go.opentelemetry.io/otel/sdk/export/metric"
 	"go.opentelemetry.io/otel/sdk/export/metric/aggregator"
-	metricsdk "go.opentelemetry.io/otel/sdk/metric"
-	"go.opentelemetry.io/otel/sdk/metric/batcher/defaultkeys"
+	"go.opentelemetry.io/otel/sdk/metric/batcher/ungrouped"
 	"go.opentelemetry.io/otel/sdk/metric/controller/push"
 	"go.opentelemetry.io/otel/sdk/metric/selector/simple"
 )
@@ -130,7 +130,7 @@ func NewExportPipeline(config Config) (*push.Controller, error) {
 	if err != nil {
 		return nil, err
 	}
-	batcher := defaultkeys.New(selector, metricsdk.NewDefaultLabelEncoder(), true)
+	batcher := ungrouped.New(selector, true)
 	pusher := push.New(batcher, exporter, time.Second)
 	pusher.Start()
 
@@ -233,13 +233,30 @@ func (e *Exporter) Export(_ context.Context, checkpointSet export.CheckpointSet)
 			}
 		}
 
+		specifiedKeyMap := make(map[core.Key]core.Value)
+		for _, kv := range record.Labels().Ordered() {
+			specifiedKeyMap[kv.Key] = kv.Value
+		}
+
+		var materializedKeys []string
+
+		if labels := record.Labels(); labels.Len() > 0 {
+			materializedKeys = append(materializedKeys, labels.Encoded())
+		}
+
+		for _, k := range desc.Keys() {
+			if _, ok := specifiedKeyMap[k]; !ok {
+				materializedKeys = append(materializedKeys, string(k))
+			}
+		}
+
 		var sb strings.Builder
 
 		sb.WriteString(desc.Name())
 
-		if labels := record.Labels(); labels.Len() > 0 {
+		if len(materializedKeys) > 0 {
 			sb.WriteRune('{')
-			sb.WriteString(labels.Encoded())
+			sb.WriteString(strings.Join(materializedKeys, ","))
 			sb.WriteRune('}')
 		}
 

exporter/metric/stdout/stdout_test.go

@@ -262,3 +262,22 @@ func TestStdoutGaugeNotSet(t *testing.T) {
 
 	require.Equal(t, `{"updates":null}`, fix.Output())
 }
+
+func TestStdoutCounterWithUnspecifiedKeys(t *testing.T) {
+	fix := newFixture(t, stdout.Config{})
+
+	checkpointSet := test.NewCheckpointSet(sdk.NewDefaultLabelEncoder())
+
+	keys := []core.Key{key.New("C"), key.New("D")}
+
+	desc := export.NewDescriptor("test.name", export.CounterKind, keys, "", "", core.Int64NumberKind, false)
+	cagg := counter.New()
+	aggtest.CheckedUpdate(fix.t, cagg, core.NewInt64Number(10), desc)
+	cagg.Checkpoint(fix.ctx, desc)
+
+	checkpointSet.Add(desc, cagg, key.String("A", "B"))
+
+	fix.Export(checkpointSet)
+
+	require.Equal(t, `{"updates":[{"name":"test.name{A=B,C,D}","sum":10}]}`, fix.Output())
+}