pdata: Add support for optional double fields

internal/testdata/metric.go

@@ -234,14 +234,14 @@ func initHistogramMetric(hm pdata.Metric) {
 	hdp0.SetStartTimestamp(TestMetricStartTimestamp)
 	hdp0.SetTimestamp(TestMetricTimestamp)
 	hdp0.SetCount(1)
-	hdp0.SetSum(15)
+	hdp0.SetSum(pdata.NewOptionalDouble(15))
 
 	hdp1 := hdps.AppendEmpty()
 	initMetricAttributes2(hdp1.Attributes())
 	hdp1.SetStartTimestamp(TestMetricStartTimestamp)
 	hdp1.SetTimestamp(TestMetricTimestamp)
 	hdp1.SetCount(1)
-	hdp1.SetSum(15)
+	hdp1.SetSum(pdata.NewOptionalDouble(15))
 	hdp1.SetBucketCounts([]uint64{0, 1})
 	exemplar := hdp1.Exemplars().AppendEmpty()
 	exemplar.SetTimestamp(TestMetricExemplarTimestamp)

model/internal/cmd/pdatagen/internal/metrics_structs.go

@@ -19,13 +19,15 @@ var metricsFile = &File{
 	imports: []string{
 		`"sort"`,
 		``,
+		`"go.opentelemetry.io/collector/model/internal/data"`,
 		`otlpmetrics "go.opentelemetry.io/collector/model/internal/data/protogen/metrics/v1"`,
 	},
 	testImports: []string{
 		`"testing"`,
 		``,
 		`"github.com/stretchr/testify/assert"`,
 		``,
+		`"go.opentelemetry.io/collector/model/internal/data"`,
 		`otlpmetrics "go.opentelemetry.io/collector/model/internal/data/protogen/metrics/v1"`,
 	},
 	structs: []baseStruct{
@@ -250,14 +252,22 @@ var histogramDataPoint = &messageValueStruct{
 		startTimeField,
 		timeField,
 		countField,
-		doubleSumField,
+		optionalSumField,
 		bucketCountsField,
 		explicitBoundsField,
 		exemplarsField,
 		dataPointFlagsField,
 	},
 }
 
+var optionalSumField = &primitiveField{
+	fieldName:       "Sum",
+	originFieldName: "Sum",
+	returnType:      "*data.OptionalDouble",
+	defaultVal:      "(*data.OptionalDouble)(nil)",
+	testVal:         "NewOptionalDouble(17.13)",
+}
+
 var exponentialHistogramDataPointSlice = &sliceOfPtrs{
 	structName: "ExponentialHistogramDataPointSlice",
 	element:    exponentialHistogramDataPoint,

model/internal/data/optional_double.go

@@ -0,0 +1,52 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package data // import "go.opentelemetry.io/collector/model/internal/data"
+
+// OptionalDouble is a custom data type that is used for all optional double fields in OTLP
+// Protobuf messages.
+type OptionalDouble struct {
+	orig float64
+}
+
+// Equal returns true if values are equal.
+func (t OptionalDouble) Equal(that OptionalDouble) bool {
+	return t.orig == that.orig
+}
+
+// NewOptionalDouble creates an OptionalDouble from a float64.
+func NewOptionalDouble(d float64) *OptionalDouble {
+	return &OptionalDouble{orig: d}
+}
+
+// TODO: implement all the methods below this line
+func (t OptionalDouble) Marshal() ([]byte, error) {
+	return []byte{}, nil
+}
+func (t *OptionalDouble) MarshalTo(data []byte) (n int, err error) {
+	return 0, nil
+}
+func (t *OptionalDouble) Unmarshal(data []byte) error {
+	return nil
+}
+func (t *OptionalDouble) Size() int {
+	return 0
+}
+
+func (t OptionalDouble) MarshalJSON() ([]byte, error) {
+	return []byte{}, nil
+}
+func (t *OptionalDouble) UnmarshalJSON(data []byte) error {
+	return nil
+}

model/internal/otlp_wrapper.go

@@ -15,6 +15,7 @@
 package internal // import "go.opentelemetry.io/collector/model/internal"
 
 import (
+	"go.opentelemetry.io/collector/model/internal/data"
 	otlpcommon "go.opentelemetry.io/collector/model/internal/data/protogen/common/v1"
 	otlplogs "go.opentelemetry.io/collector/model/internal/data/protogen/logs/v1"
 	otlpmetrics "go.opentelemetry.io/collector/model/internal/data/protogen/metrics/v1"
@@ -163,7 +164,7 @@ func intHistogramToHistogram(src *otlpmetrics.Metric_IntHistogram) *otlpmetrics.
 			TimeUnixNano:      datapoint.TimeUnixNano,
 			Count:             datapoint.Count,
 			StartTimeUnixNano: datapoint.StartTimeUnixNano,
-			Sum:               float64(datapoint.Sum),
+			Sum:               data.NewOptionalDouble(float64(datapoint.Sum)),
 			BucketCounts:      datapoint.BucketCounts,
 			ExplicitBounds:    datapoint.ExplicitBounds,
 			Exemplars:         intExemplarToExemplar(datapoint.Exemplars),

model/internal/otlp_wrappers_test.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
+	"go.opentelemetry.io/collector/model/internal/data"
 	otlpcommon "go.opentelemetry.io/collector/model/internal/data/protogen/common/v1"
 	otlpmetrics "go.opentelemetry.io/collector/model/internal/data/protogen/metrics/v1"
 	otlptrace "go.opentelemetry.io/collector/model/internal/data/protogen/trace/v1"
@@ -134,7 +135,7 @@ func TestDeprecatedIntHistogram(t *testing.T) {
 									},
 									BucketCounts:      []uint64{11, 16, 2},
 									ExplicitBounds:    []float64{3, 4},
-									Sum:               10.1,
+									Sum:               *data.NewOptionalDouble(10.1),
 									StartTimeUnixNano: 0,
 									TimeUnixNano:      1,
 									Count:             29,
@@ -155,7 +156,7 @@ func TestDeprecatedIntHistogram(t *testing.T) {
 								},
 								BucketCounts:      []uint64{11, 16, 2},
 								ExplicitBounds:    []float64{3, 4},
-								Sum:               10.1,
+								Sum:               *data.NewOptionalDouble(10.1),
 								StartTimeUnixNano: 0,
 								TimeUnixNano:      1,
 								Count:             29,
@@ -202,7 +203,7 @@ func TestDeprecatedIntHistogram(t *testing.T) {
 								},
 								BucketCounts:      []uint64{10, 15, 1},
 								ExplicitBounds:    []float64{1, 2},
-								Sum:               10.0,
+								Sum:               *data.NewOptionalDouble(10.0),
 								StartTimeUnixNano: 2,
 								TimeUnixNano:      3,
 								Count:             26,
@@ -249,7 +250,7 @@ func TestDeprecatedIntHistogram(t *testing.T) {
 								},
 								BucketCounts:      []uint64{10, 15, 1},
 								ExplicitBounds:    []float64{1, 2},
-								Sum:               10.0,
+								Sum:               *data.NewOptionalDouble(10.0),
 								StartTimeUnixNano: 2,
 								TimeUnixNano:      3,
 								Count:             26,

model/pdata/metrics.go

@@ -16,6 +16,7 @@ package pdata // import "go.opentelemetry.io/collector/model/pdata"
 
 import (
 	"go.opentelemetry.io/collector/model/internal"
+	"go.opentelemetry.io/collector/model/internal/data"
 	otlpmetrics "go.opentelemetry.io/collector/model/internal/data/protogen/metrics/v1"
 )
 
@@ -350,3 +351,8 @@ func (ms Exemplar) Type() MetricValueType {
 	}
 	return MetricValueTypeNone
 }
+
+// NewOptionalDouble creates an data.OptionalDouble from a float64.
+func NewOptionalDouble(val float64) *data.OptionalDouble {
+	return data.NewOptionalDouble(val)
+}

proto_patch.sed

@@ -50,4 +50,13 @@ s+repeated Exemplar exemplars = \(.*\);+repeated Exemplar exemplars = \1\
   [ (gogoproto.nullable) = false ];+g
 
 s+Buckets \(.*\)tive = \(.*\);+Buckets \1tive = \2\
-  [ (gogoproto.nullable) = false ];+g
+  [ (gogoproto.nullable) = false ];+g
+
+s+optional double \(.*\);+OptionalDouble \1\
+  [\
+    (gogoproto.customtype) = "go.opentelemetry.io/collector/model/internal/data.OptionalDouble"\
+  ];\
+  \
+  message OptionalDouble {\
+    double Sum = 1;\
+  }+g