[tanzuobservability exporter] Add consumer for sum metrics. (open-tel…

…emetry#6385)

* [tanzuobservability exporter] Add consumer for sum metrics.

* Function headers to be more readable.

pushGaugeSingleNumberDataPoint->pushGaugeNumberDataPoint
pushSingleNumberDataPoint->pushNumberDataPoint

* Break verifySumConsumer into four separate tests.

* Minor changes to tests.

exporter/tanzuobservabilityexporter/metrics.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"sync/atomic"
 
+	"github.com/wavefronthq/wavefront-sdk-go/senders"
 	"go.opentelemetry.io/collector/model/pdata"
 	"go.uber.org/multierr"
 	"go.uber.org/zap"
@@ -33,6 +34,7 @@ const (
 
 var (
 	typeIsGaugeTags = map[string]string{"type": "gauge"}
+	typeIsSumTags   = map[string]string{"type": "sum"}
 )
 
 // metricsConsumer instances consume OTEL metrics
@@ -149,7 +151,8 @@ type counter struct {
 // the metric to be reported. tags is the tags for the metric. sender is what
 // sends the metric to tanzu observability. Any errors get added to errs.
 func (c *counter) Report(
-	name string, tags map[string]string, sender gaugeSender, errs *[]error) {
+	name string, tags map[string]string, sender gaugeSender, errs *[]error,
+) {
 	err := sender.SendMetric(name, float64(c.Get()), 0, "", tags)
 	if err != nil {
 		*errs = append(*errs, err)
@@ -188,6 +191,32 @@ func getValue(numberDataPoint pdata.NumberDataPoint) (float64, error) {
 	}
 }
 
+// pushGaugeNumberDataPoint sends a metric as a gauge metric to tanzu
+// observability. metric is the metric to send. numberDataPoint is the value
+// of the metric. Any errors get appended to errs. sender is what sends the
+// gauge metric to tanzu observability. logger is the logger. missingValues
+// keeps track of metrics with missing values.
+func pushGaugeNumberDataPoint(
+	metric pdata.Metric,
+	numberDataPoint pdata.NumberDataPoint,
+	errs *[]error,
+	sender gaugeSender,
+	logger *zap.Logger,
+	missingValues *counter,
+) {
+	tags := attributesToTags(numberDataPoint.Attributes())
+	ts := numberDataPoint.Timestamp().AsTime().Unix()
+	value, err := getValue(numberDataPoint)
+	if err != nil {
+		logMissingValue(metric, logger, missingValues)
+		return
+	}
+	err = sender.SendMetric(metric.Name(), value, ts, "", tags)
+	if err != nil {
+		*errs = append(*errs, err)
+	}
+}
+
 // gaugeSender sends gauge metrics to tanzu observability
 type gaugeSender interface {
 	SendMetric(name string, value float64, ts int64, source string, tags map[string]string) error
@@ -239,7 +268,13 @@ func (g *gaugeConsumer) Consume(metric pdata.Metric, errs *[]error) {
 	gauge := metric.Gauge()
 	numberDataPoints := gauge.DataPoints()
 	for i := 0; i < numberDataPoints.Len(); i++ {
-		g.pushSingleNumberDataPoint(metric, numberDataPoints.At(i), errs)
+		pushGaugeNumberDataPoint(
+			metric,
+			numberDataPoints.At(i),
+			errs,
+			g.sender,
+			g.logger,
+			&g.missingValues)
 	}
 }
 
@@ -249,16 +284,63 @@ func (g *gaugeConsumer) PushInternalMetrics(errs *[]error) {
 	}
 }
 
-func (g *gaugeConsumer) pushSingleNumberDataPoint(
-	metric pdata.Metric, numberDataPoint pdata.NumberDataPoint, errs *[]error) {
+type sumConsumer struct {
+	sender                senders.MetricSender
+	logger                *zap.Logger
+	missingValues         counter
+	reportInternalMetrics bool
+}
+
+func newSumConsumer(sender senders.MetricSender, options *consumerOptions) typedMetricConsumer {
+	var fixedOptions consumerOptions
+	if options != nil {
+		fixedOptions = *options
+	}
+	fixedOptions.replaceZeroFieldsWithDefaults()
+	return &sumConsumer{
+		sender:                sender,
+		logger:                fixedOptions.Logger,
+		reportInternalMetrics: fixedOptions.ReportInternalMetrics,
+	}
+}
+
+func (s *sumConsumer) Type() pdata.MetricDataType {
+	return pdata.MetricDataTypeSum
+}
+
+func (s *sumConsumer) Consume(metric pdata.Metric, errs *[]error) {
+	sum := metric.Sum()
+	isDelta := sum.AggregationTemporality() == pdata.MetricAggregationTemporalityDelta
+	numberDataPoints := sum.DataPoints()
+	for i := 0; i < numberDataPoints.Len(); i++ {
+		// If sum metric is a delta type, send it to tanzu observability as a
+		// delta counter. Otherwise, send it to tanzu observability as a gauge
+		// metric.
+		if isDelta {
+			s.pushNumberDataPoint(metric, numberDataPoints.At(i), errs)
+		} else {
+			pushGaugeNumberDataPoint(
+				metric, numberDataPoints.At(i), errs, s.sender, s.logger, &s.missingValues)
+		}
+	}
+}
+
+func (s *sumConsumer) PushInternalMetrics(errs *[]error) {
+	if s.reportInternalMetrics {
+		s.missingValues.Report(missingValueMetricName, typeIsSumTags, s.sender, errs)
+	}
+}
+
+func (s *sumConsumer) pushNumberDataPoint(
+	metric pdata.Metric, numberDataPoint pdata.NumberDataPoint, errs *[]error,
+) {
 	tags := attributesToTags(numberDataPoint.Attributes())
-	ts := numberDataPoint.Timestamp().AsTime().Unix()
 	value, err := getValue(numberDataPoint)
 	if err != nil {
-		logMissingValue(metric, g.logger, &g.missingValues)
+		logMissingValue(metric, s.logger, &s.missingValues)
 		return
 	}
-	err = g.sender.SendMetric(metric.Name(), value, ts, "", tags)
+	err = s.sender.SendDeltaCounter(metric.Name(), value, "", tags)
 	if err != nil {
 		*errs = append(*errs, err)
 	}