Add initial draft of the oneof generator, fixes issue in contrib (#1677)

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

cmd/pdatagen/internal/base_fields.go

@@ -314,3 +314,27 @@ func (ptf *primitiveTypedField) generateCopyToValue(sb *strings.Builder) {
 }
 
 var _ baseField = (*primitiveTypedField)(nil)
+
+// oneofField is used in case where the proto defines an "oneof".
+type oneofField struct {
+	copyFuncName    string
+	originFieldName string
+	testVal         string
+	fillTestName    string
+}
+
+func (one oneofField) generateAccessors(*messageStruct, *strings.Builder) {}
+
+func (one oneofField) generateAccessorsTest(*messageStruct, *strings.Builder) {}
+
+func (one oneofField) generateSetWithTestValue(sb *strings.Builder) {
+	sb.WriteString("\t(*tv.orig)." + one.originFieldName + " = " + one.testVal + "\n")
+	sb.WriteString("\ttv." + one.fillTestName + "().InitEmpty()\n")
+	sb.WriteString("\tfillTest" + one.fillTestName + "(tv." + one.fillTestName + "())")
+}
+
+func (one oneofField) generateCopyToValue(sb *strings.Builder) {
+	sb.WriteString("\t" + one.copyFuncName + "((*ms.orig), (*dest.orig))")
+}
+
+var _ baseField = (*oneofField)(nil)

cmd/pdatagen/internal/metrics_structs.go

@@ -118,6 +118,7 @@ var metric = &messageStruct{
 			defaultVal:      `""`,
 			testVal:         `"1"`,
 		},
+		oneofDataField,
 	},
 }
 
@@ -419,3 +420,10 @@ var aggregationTemporalityField = &primitiveTypedField{
 	defaultVal:      "AggregationTemporalityUnspecified",
 	testVal:         "AggregationTemporalityCumulative",
 }
+
+var oneofDataField = &oneofField{
+	copyFuncName:    "copyData",
+	originFieldName: "Data",
+	testVal:         "&otlpmetrics.Metric_IntGauge{}",
+	fillTestName:    "IntGauge",
+}

consumer/pdata/metric.go

@@ -201,6 +201,35 @@ func (ms Metric) SetDoubleHistogram(data DoubleHistogram) {
 	}
 }
 
+func copyData(src, dest *otlpmetrics.Metric) {
+	switch (src).Data.(type) {
+	case *otlpmetrics.Metric_IntGauge:
+		dest.Data = &otlpmetrics.Metric_IntGauge{
+			IntGauge: src.Data.(*otlpmetrics.Metric_IntGauge).IntGauge,
+		}
+	case *otlpmetrics.Metric_DoubleGauge:
+		dest.Data = &otlpmetrics.Metric_DoubleGauge{
+			DoubleGauge: src.Data.(*otlpmetrics.Metric_DoubleGauge).DoubleGauge,
+		}
+	case *otlpmetrics.Metric_IntSum:
+		dest.Data = &otlpmetrics.Metric_IntSum{
+			IntSum: src.Data.(*otlpmetrics.Metric_IntSum).IntSum,
+		}
+	case *otlpmetrics.Metric_DoubleSum:
+		dest.Data = &otlpmetrics.Metric_DoubleSum{
+			DoubleSum: src.Data.(*otlpmetrics.Metric_DoubleSum).DoubleSum,
+		}
+	case *otlpmetrics.Metric_IntHistogram:
+		dest.Data = &otlpmetrics.Metric_IntHistogram{
+			IntHistogram: src.Data.(*otlpmetrics.Metric_IntHistogram).IntHistogram,
+		}
+	case *otlpmetrics.Metric_DoubleHistogram:
+		dest.Data = &otlpmetrics.Metric_DoubleHistogram{
+			DoubleHistogram: src.Data.(*otlpmetrics.Metric_DoubleHistogram).DoubleHistogram,
+		}
+	}
+}
+
 // DeprecatedNewResource temporary public function.
 func DeprecatedNewResource(orig **otlpresource.Resource) Resource {
 	return newResource(orig)

consumer/pdata/metric_test.go

@@ -25,6 +25,72 @@ import (
 	otlpmetrics "go.opentelemetry.io/collector/internal/data/opentelemetry-proto-gen/metrics/v1"
 )
 
+func TestCopyData(t *testing.T) {
+	tests := []struct {
+		name string
+		src  *otlpmetrics.Metric
+	}{
+		{
+			name: "IntGauge",
+			src: &otlpmetrics.Metric{
+				Data: &otlpmetrics.Metric_IntGauge{
+					IntGauge: &otlpmetrics.IntGauge{},
+				},
+			},
+		},
+		{
+			name: "DoubleGauge",
+			src: &otlpmetrics.Metric{
+				Data: &otlpmetrics.Metric_DoubleGauge{
+					DoubleGauge: &otlpmetrics.DoubleGauge{},
+				},
+			},
+		},
+		{
+			name: "IntSum",
+			src: &otlpmetrics.Metric{
+				Data: &otlpmetrics.Metric_IntSum{
+					IntSum: &otlpmetrics.IntSum{},
+				},
+			},
+		},
+		{
+			name: "DoubleSum",
+			src: &otlpmetrics.Metric{
+				Data: &otlpmetrics.Metric_DoubleSum{
+					DoubleSum: &otlpmetrics.DoubleSum{},
+				},
+			},
+		},
+		{
+			name: "IntHistogram",
+			src: &otlpmetrics.Metric{
+				Data: &otlpmetrics.Metric_IntHistogram{
+					IntHistogram: &otlpmetrics.IntHistogram{},
+				},
+			},
+		},
+		{
+			name: "DoubleHistogram",
+			src: &otlpmetrics.Metric{
+				Data: &otlpmetrics.Metric_DoubleHistogram{
+					DoubleHistogram: &otlpmetrics.DoubleHistogram{},
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			dest := &otlpmetrics.Metric{}
+			assert.Nil(t, dest.Data)
+			assert.NotNil(t, test.src.Data)
+			copyData(test.src, dest)
+			assert.EqualValues(t, test.src, dest)
+		})
+	}
+}
+
 func TestResourceMetricsWireCompatibility(t *testing.T) {
 	// This test verifies that OTLP ProtoBufs generated using goproto lib in
 	// opentelemetry-proto repository OTLP ProtoBufs generated using gogoproto lib in