Add support for V1 series endpoint

Co-authored by: Jesus Vazquez <[email protected]>:

receiver/datadogreceiver/metrics_translator.go

@@ -3,6 +3,8 @@
 
 package datadogreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver"
 import (
+	datadogV1 "github.com/DataDog/datadog-api-client-go/v2/api/datadogV1"
+	"go.opentelemetry.io/collector/pdata/pmetric"
 	"sync"
 
 	"go.opentelemetry.io/collector/component"
@@ -13,12 +15,104 @@ import (
 
 type MetricsTranslator struct {
 	sync.RWMutex
-	buildInfo component.BuildInfo
-	lastTs    map[identity.Stream]pcommon.Timestamp
+	buildInfo  component.BuildInfo
+	lastTs     map[identity.Stream]pcommon.Timestamp
+	stringPool *StringPool
 }
 
 func newMetricsTranslator() *MetricsTranslator {
 	return &MetricsTranslator{
-		lastTs: make(map[identity.Stream]pcommon.Timestamp),
+		lastTs:     make(map[identity.Stream]pcommon.Timestamp),
+		stringPool: newStringPool(),
 	}
 }
+
+func (mt *MetricsTranslator) streamHasTimestamp(stream identity.Stream) (pcommon.Timestamp, bool) {
+	mt.RLock()
+	defer mt.RUnlock()
+	ts, ok := mt.lastTs[stream]
+	return ts, ok
+}
+
+func (mt *MetricsTranslator) updateLastTsForStream(stream identity.Stream, ts pcommon.Timestamp) {
+	mt.Lock()
+	defer mt.Unlock()
+	mt.lastTs[stream] = ts
+}
+
+const (
+	TypeGauge string = "gauge"
+	TypeRate  string = "rate"
+	TypeCount string = "count"
+)
+
+type SeriesList struct {
+	Series []datadogV1.Series `json:"series"`
+}
+
+func translateMetricsV1(series SeriesList, mt *MetricsTranslator) pmetric.Metrics {
+	bt := newBatcher()
+	bt.Metrics = pmetric.NewMetrics()
+
+	for _, serie := range series.Series {
+		var dps pmetric.NumberDataPointSlice
+
+		dimensions := parseSeriesProperties(serie.Metric, serie.GetType(), serie.GetTags(), serie.GetHost(), mt.buildInfo.Version, mt.stringPool)
+		metric, metricID := bt.Lookup(dimensions)
+
+		switch serie.GetType() {
+		case TypeCount:
+			metric.Sum().SetAggregationTemporality(pmetric.AggregationTemporalityDelta)
+			metric.Sum().SetIsMonotonic(false) // See https://docs.datadoghq.com/metrics/types/?tab=count#definition
+			dps = metric.Sum().DataPoints()
+		case TypeGauge:
+			dps = metric.Gauge().DataPoints()
+		case TypeRate:
+			metric.Sum().SetAggregationTemporality(pmetric.AggregationTemporalityDelta)
+			dps = metric.Sum().DataPoints()
+		default:
+			// Type is unset/unspecified
+			continue
+		}
+
+		dps.EnsureCapacity(len(serie.Points))
+
+		var dp pmetric.NumberDataPoint
+		var ts uint64
+		var value float64
+		// The Datadog API returns a slice of slices of points [][]*float64 which is a bit awkward to work with.
+		// It looks like this:
+		// points := [][]*float64{
+		// 	{&timestamp1, &value1},
+		// 	{&timestamp2, &value2},
+		// }
+		// We need to flatten this to a slice of *float64 to work with it. And we know that in that slice, the first
+		// element is the timestamp and the second is the value.
+		for _, points := range serie.Points {
+			if len(points) != 2 {
+				continue // The datapoint is missing a timestamp and/or value, so this point should be skipped
+			}
+			ts = uint64(*points[0])
+			value = *points[1]
+
+			dp = dps.AppendEmpty()
+			dp.SetTimestamp(pcommon.Timestamp(ts * 1_000_000_000)) // OTel uses nanoseconds, while Datadog uses seconds
+
+			if *serie.Type == TypeRate {
+				if serie.Interval.IsSet() {
+					value *= float64(serie.GetInterval())
+				}
+			}
+			dp.SetDoubleValue(value)
+			dimensions.dpAttrs.CopyTo(dp.Attributes())
+
+			stream := identity.OfStream(metricID, dp)
+			ts, ok := mt.streamHasTimestamp(stream)
+			if ok {
+				dp.SetStartTimestamp(ts)
+			}
+			mt.updateLastTsForStream(stream, dp.Timestamp())
+		}
+	}
+	return bt.Metrics
+}

receiver/datadogreceiver/receiver.go

@@ -5,8 +5,10 @@ package datadogreceiver // import "github.com/open-telemetry/opentelemetry-colle
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"net/http"
 
 	pb "github.com/DataDog/datadog-agent/pkg/proto/pbgo/trace"
@@ -143,9 +145,34 @@ func (ddr *datadogReceiver) handleV1Series(w http.ResponseWriter, req *http.Requ
 		ddr.tReceiver.EndMetricsOp(obsCtx, "datadog", *metricsCount, err)
 	}(&metricsCount)
 
-	err = fmt.Errorf("series v1 endpoint not implemented")
-	http.Error(w, err.Error(), http.StatusMethodNotAllowed)
-	ddr.params.Logger.Warn("metrics consumer errored out", zap.Error(err))
+	buf := getBuffer()
+	defer putBuffer(buf)
+	if _, err = io.Copy(buf, req.Body); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		ddr.params.Logger.Error(err.Error())
+		return
+	}
+
+	seriesList := SeriesList{}
+	err = json.Unmarshal(buf.Bytes(), &seriesList)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		ddr.params.Logger.Error(err.Error())
+		return
+	}
+
+	metrics := translateMetricsV1(seriesList, ddr.metricsTranslator)
+	metricsCount = metrics.DataPointCount()
+
+	err = ddr.nextMetricsConsumer.ConsumeMetrics(obsCtx, metrics)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		ddr.params.Logger.Error("metrics consumer errored out", zap.Error(err))
+		return
+	}
+
+	w.WriteHeader(http.StatusAccepted)
+	_, err = w.Write([]byte("OK"))
 }
 
 // handleV2Series handles the v2 series endpoint https://docs.datadoghq.com/api/latest/metrics/#submit-metrics