Merge branch 'main' into gustavo.prom_with_namespace

.gitignore

@@ -7,6 +7,7 @@ Thumbs.db
 *.iml
 *.so
 coverage.*
+go.work
 
 gen/
 

CHANGELOG.md

@@ -27,6 +27,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - `TracerProvider` allows calling `Tracer()` while it's shutting down.
   It used to deadlock. (#3924)
 - Use the SDK version for the Telemetry SDK resource detector in `go.opentelemetry.io/otel/sdk/resource`. (#3949)
+- Automatically figure out the default aggregation with `aggregation.Default`. (#3967)
 
 ## [1.15.0-rc.2/0.38.0-rc.2] 2023-03-23
 

attribute/set.go

@@ -98,7 +98,7 @@ func (l *Set) Len() int {
 
 // Get returns the KeyValue at ordered position idx in this set.
 func (l *Set) Get(idx int) (KeyValue, bool) {
-	if l == nil {
+	if l == nil || !l.equivalent.Valid() {
 		return KeyValue{}, false
 	}
 	value := l.equivalent.reflectValue()
@@ -114,7 +114,7 @@ func (l *Set) Get(idx int) (KeyValue, bool) {
 
 // Value returns the value of a specified key in this set.
 func (l *Set) Value(k Key) (Value, bool) {
-	if l == nil {
+	if l == nil || !l.equivalent.Valid() {
 		return Value{}, false
 	}
 	rValue := l.equivalent.reflectValue()

attribute/set_test.go

@@ -15,9 +15,11 @@
 package attribute_test
 
 import (
+	"reflect"
 	"regexp"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"go.opentelemetry.io/otel/attribute"
@@ -188,3 +190,38 @@ func TestLookup(t *testing.T) {
 	_, has = set.Value("D")
 	require.False(t, has)
 }
+
+func TestZeroSetExportedMethodsNoPanic(t *testing.T) {
+	rType := reflect.TypeOf((*attribute.Set)(nil))
+	rVal := reflect.ValueOf(&attribute.Set{})
+	for n := 0; n < rType.NumMethod(); n++ {
+		mType := rType.Method(n)
+		if !mType.IsExported() {
+			t.Logf("ignoring unexported %s", mType.Name)
+			continue
+		}
+		t.Run(mType.Name, func(t *testing.T) {
+			m := rVal.MethodByName(mType.Name)
+			if !m.IsValid() {
+				t.Errorf("unknown method: %s", mType.Name)
+			}
+			assert.NotPanics(t, func() { _ = m.Call(args(mType)) })
+		})
+	}
+}
+
+func args(m reflect.Method) []reflect.Value {
+	numIn := m.Type.NumIn() - 1 // Do not include the receiver arg.
+	if numIn <= 0 {
+		return nil
+	}
+	if m.Type.IsVariadic() {
+		numIn--
+	}
+	out := make([]reflect.Value, numIn)
+	for i := range out {
+		aType := m.Type.In(i + 1) // Skip receiver arg.
+		out[i] = reflect.New(aType).Elem()
+	}
+	return out
+}

sdk/metric/pipeline.go

@@ -390,6 +390,8 @@ func (i *inserter[N]) streamID(kind InstrumentKind, stream Stream) streamID {
 // returned.
 func (i *inserter[N]) aggregator(agg aggregation.Aggregation, kind InstrumentKind, temporality metricdata.Temporality, monotonic bool) (internal.Aggregator[N], error) {
 	switch a := agg.(type) {
+	case aggregation.Default:
+		return i.aggregator(DefaultAggregationSelector(kind), kind, temporality, monotonic)
 	case aggregation.Drop:
 		return nil, nil
 	case aggregation.LastValue:
@@ -444,6 +446,8 @@ func (i *inserter[N]) aggregator(agg aggregation.Aggregation, kind InstrumentKin
 // | Observable Gauge         | X    | X         |     |           |                       |.
 func isAggregatorCompatible(kind InstrumentKind, agg aggregation.Aggregation) error {
 	switch agg.(type) {
+	case aggregation.Default:
+		return nil
 	case aggregation.ExplicitBucketHistogram:
 		if kind == InstrumentKindCounter || kind == InstrumentKindHistogram {
 			return nil

sdk/metric/pipeline_registry_test.go

@@ -199,11 +199,52 @@ func testCreateAggregators[N int64 | float64](t *testing.T) {
 			wantLen:  2,
 		},
 		{
-			name:    "reader with invalid aggregation should error",
-			reader:  NewManualReader(WithAggregationSelector(func(ik InstrumentKind) aggregation.Aggregation { return aggregation.Default{} })),
-			views:   []View{defaultView},
-			inst:    instruments[InstrumentKindCounter],
-			wantErr: errCreatingAggregators,
+			name:     "reader with default aggregation should figure out a Counter",
+			reader:   NewManualReader(WithAggregationSelector(func(ik InstrumentKind) aggregation.Aggregation { return aggregation.Default{} })),
+			views:    []View{defaultView},
+			inst:     instruments[InstrumentKindCounter],
+			wantKind: internal.NewCumulativeSum[N](true),
+			wantLen:  1,
+		},
+		{
+			name:     "reader with default aggregation should figure out an UpDownCounter",
+			reader:   NewManualReader(WithAggregationSelector(func(ik InstrumentKind) aggregation.Aggregation { return aggregation.Default{} })),
+			views:    []View{defaultView},
+			inst:     instruments[InstrumentKindUpDownCounter],
+			wantKind: internal.NewCumulativeSum[N](true),
+			wantLen:  1,
+		},
+		{
+			name:     "reader with default aggregation should figure out an Histogram",
+			reader:   NewManualReader(WithAggregationSelector(func(ik InstrumentKind) aggregation.Aggregation { return aggregation.Default{} })),
+			views:    []View{defaultView},
+			inst:     instruments[InstrumentKindHistogram],
+			wantKind: internal.NewCumulativeHistogram[N](aggregation.ExplicitBucketHistogram{}),
+			wantLen:  1,
+		},
+		{
+			name:     "reader with default aggregation should figure out an ObservableCounter",
+			reader:   NewManualReader(WithAggregationSelector(func(ik InstrumentKind) aggregation.Aggregation { return aggregation.Default{} })),
+			views:    []View{defaultView},
+			inst:     instruments[InstrumentKindObservableCounter],
+			wantKind: internal.NewPrecomputedCumulativeSum[N](true),
+			wantLen:  1,
+		},
+		{
+			name:     "reader with default aggregation should figure out an ObservableUpDownCounter",
+			reader:   NewManualReader(WithAggregationSelector(func(ik InstrumentKind) aggregation.Aggregation { return aggregation.Default{} })),
+			views:    []View{defaultView},
+			inst:     instruments[InstrumentKindObservableUpDownCounter],
+			wantKind: internal.NewPrecomputedCumulativeSum[N](true),
+			wantLen:  1,
+		},
+		{
+			name:     "reader with default aggregation should figure out an ObservableGauge",
+			reader:   NewManualReader(WithAggregationSelector(func(ik InstrumentKind) aggregation.Aggregation { return aggregation.Default{} })),
+			views:    []View{defaultView},
+			inst:     instruments[InstrumentKindObservableGauge],
+			wantKind: internal.NewLastValue[N](),
+			wantLen:  1,
 		},
 		{
 			name:    "view with invalid aggregation should error",
@@ -594,12 +635,6 @@ func TestIsAggregatorCompatible(t *testing.T) {
 			agg:  aggregation.ExplicitBucketHistogram{},
 			want: errIncompatibleAggregation,
 		},
-		{
-			name: "Default aggregation should error",
-			kind: InstrumentKindCounter,
-			agg:  aggregation.Default{},
-			want: errUnknownAggregation,
-		},
 		{
 			name: "unknown kind with Sum should error",
 			kind: undefinedInstrument,