[receiver/signalfx] Accept otlp metrics (#31008)

**Description:** Accept OTLP payloads on /v2/datapoint api of the SignalFx receiver

**Link to tracking Issue:** #26298

Author: jinja2

.chloggen/signalfx-recv-otlp.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: receiver/signalfx
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Accept otlp protobuf requests when content-type is "application/x-protobuf;format=otlp"
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [31052]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

receiver/signalfxreceiver/receiver.go

@@ -20,6 +20,8 @@ import (
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/pdata/plog"
+	"go.opentelemetry.io/collector/pdata/pmetric"
+	"go.opentelemetry.io/collector/pdata/pmetric/pmetricotlp"
 	"go.opentelemetry.io/collector/receiver"
 	"go.opentelemetry.io/collector/receiver/receiverhelper"
 	"go.uber.org/zap"
@@ -32,9 +34,11 @@ import (
 const (
 	defaultServerTimeout = 20 * time.Second
 
-	responseOK                      = "OK"
-	responseInvalidMethod           = "Only \"POST\" method is supported"
-	responseInvalidContentType      = "\"Content-Type\" must be \"application/x-protobuf\""
+	responseOK                       = "OK"
+	responseInvalidMethod            = "Only \"POST\" method is supported"
+	responseEventsInvalidContentType = "\"Content-Type\" must be \"application/x-protobuf\""
+
+	responseInvalidContentType      = "\"Content-Type\" must be either \"application/x-protobuf\" or \"application/x-protobuf;format=otlp\""
 	responseInvalidEncoding         = "\"Content-Encoding\" must be \"gzip\" or empty"
 	responseErrGzipReader           = "Error on gzip body"
 	responseErrReadBody             = "Failed to read message body"
@@ -45,22 +49,24 @@ const (
 
 	// Centralizing some HTTP and related string constants.
 	protobufContentType       = "application/x-protobuf"
+	otlpProtobufContentType   = "application/x-protobuf;format=otlp"
 	gzipEncoding              = "gzip"
 	httpContentTypeHeader     = "Content-Type"
 	httpContentEncodingHeader = "Content-Encoding"
 )
 
 var (
-	okRespBody               = initJSONResponse(responseOK)
-	invalidMethodRespBody    = initJSONResponse(responseInvalidMethod)
-	invalidContentRespBody   = initJSONResponse(responseInvalidContentType)
-	invalidEncodingRespBody  = initJSONResponse(responseInvalidEncoding)
-	errGzipReaderRespBody    = initJSONResponse(responseErrGzipReader)
-	errReadBodyRespBody      = initJSONResponse(responseErrReadBody)
-	errUnmarshalBodyRespBody = initJSONResponse(responseErrUnmarshalBody)
-	errNextConsumerRespBody  = initJSONResponse(responseErrNextConsumer)
-	errLogsNotConfigured     = initJSONResponse(responseErrLogsNotConfigured)
-	errMetricsNotConfigured  = initJSONResponse(responseErrMetricsNotConfigured)
+	okRespBody                   = initJSONResponse(responseOK)
+	invalidMethodRespBody        = initJSONResponse(responseInvalidMethod)
+	invalidContentRespBody       = initJSONResponse(responseInvalidContentType)
+	invalidEventsContentRespBody = initJSONResponse(responseEventsInvalidContentType)
+	invalidEncodingRespBody      = initJSONResponse(responseInvalidEncoding)
+	errGzipReaderRespBody        = initJSONResponse(responseErrGzipReader)
+	errReadBodyRespBody          = initJSONResponse(responseErrReadBody)
+	errUnmarshalBodyRespBody     = initJSONResponse(responseErrUnmarshalBody)
+	errNextConsumerRespBody      = initJSONResponse(responseErrNextConsumer)
+	errLogsNotConfigured         = initJSONResponse(responseErrLogsNotConfigured)
+	errMetricsNotConfigured      = initJSONResponse(responseErrMetricsNotConfigured)
 
 	translator = &signalfx.ToTranslator{}
 )
@@ -166,16 +172,6 @@ func (r *sfxReceiver) Shutdown(context.Context) error {
 }
 
 func (r *sfxReceiver) readBody(ctx context.Context, resp http.ResponseWriter, req *http.Request) ([]byte, bool) {
-	if req.Method != http.MethodPost {
-		r.failRequest(ctx, resp, http.StatusBadRequest, invalidMethodRespBody, nil)
-		return nil, false
-	}
-
-	if req.Header.Get(httpContentTypeHeader) != protobufContentType {
-		r.failRequest(ctx, resp, http.StatusUnsupportedMediaType, invalidContentRespBody, nil)
-		return nil, false
-	}
-
 	encoding := req.Header.Get(httpContentEncodingHeader)
 	if encoding != "" && encoding != gzipEncoding {
 		r.failRequest(ctx, resp, http.StatusUnsupportedMediaType, invalidEncodingRespBody, nil)
@@ -221,40 +217,64 @@ func (r *sfxReceiver) handleDatapointReq(resp http.ResponseWriter, req *http.Req
 		return
 	}
 
-	body, ok := r.readBody(ctx, resp, req)
-	if !ok {
+	if req.Method != http.MethodPost {
+		r.failRequest(ctx, resp, http.StatusBadRequest, invalidMethodRespBody, nil)
 		return
 	}
 
-	msg := &sfxpb.DataPointUploadMessage{}
-	if err := msg.Unmarshal(body); err != nil {
-		r.failRequest(ctx, resp, http.StatusBadRequest, errUnmarshalBodyRespBody, err)
+	otlpFormat := false
+	switch req.Header.Get(httpContentTypeHeader) {
+	case protobufContentType:
+	case otlpProtobufContentType:
+		otlpFormat = true
+	default:
+		r.failRequest(ctx, resp, http.StatusUnsupportedMediaType, invalidContentRespBody, nil)
 		return
 	}
 
-	if len(msg.Datapoints) == 0 {
-		r.obsrecv.EndMetricsOp(ctx, metadata.Type.String(), 0, nil)
-		_, _ = resp.Write(okRespBody)
+	body, ok := r.readBody(ctx, resp, req)
+	if !ok {
 		return
 	}
 
-	md, err := translator.ToMetrics(msg.Datapoints)
-	if err != nil {
-		r.settings.Logger.Debug("SignalFx conversion error", zap.Error(err))
-	}
+	r.settings.Logger.Debug("Handling metrics data")
 
-	if r.config.AccessTokenPassthrough {
-		if accessToken := req.Header.Get(splunk.SFxAccessTokenHeader); accessToken != "" {
-			for i := 0; i < md.ResourceMetrics().Len(); i++ {
-				rm := md.ResourceMetrics().At(i)
-				res := rm.Resource()
-				res.Attributes().PutStr(splunk.SFxAccessTokenLabel, accessToken)
-			}
+	var md pmetric.Metrics
+
+	if otlpFormat {
+		r.settings.Logger.Debug("Received request is in OTLP format")
+		otlpreq := pmetricotlp.NewExportRequest()
+		if err := otlpreq.UnmarshalProto(body); err != nil {
+			r.settings.Logger.Debug("OTLP data unmarshalling failed", zap.Error(err))
+			r.failRequest(ctx, resp, http.StatusBadRequest, errUnmarshalBodyRespBody, err)
+			return
 		}
+		md = otlpreq.Metrics()
+	} else {
+		msg := &sfxpb.DataPointUploadMessage{}
+		err := msg.Unmarshal(body)
+		if err != nil {
+			r.failRequest(ctx, resp, http.StatusBadRequest, errUnmarshalBodyRespBody, err)
+			return
+		}
+
+		md, err = translator.ToMetrics(msg.Datapoints)
+		if err != nil {
+			r.settings.Logger.Debug("SignalFx conversion error", zap.Error(err))
+		}
+	}
+
+	dataPointCount := md.DataPointCount()
+	if dataPointCount == 0 {
+		r.obsrecv.EndMetricsOp(ctx, metadata.Type.String(), 0, nil)
+		_, _ = resp.Write(okRespBody)
+		return
 	}
 
-	err = r.metricsConsumer.ConsumeMetrics(ctx, md)
-	r.obsrecv.EndMetricsOp(ctx, metadata.Type.String(), len(msg.Datapoints), err)
+	r.addAccessTokenLabel(md, req)
+
+	err := r.metricsConsumer.ConsumeMetrics(ctx, md)
+	r.obsrecv.EndMetricsOp(ctx, metadata.Type.String(), dataPointCount, err)
 
 	r.writeResponse(ctx, resp, err)
 }
@@ -267,6 +287,16 @@ func (r *sfxReceiver) handleEventReq(resp http.ResponseWriter, req *http.Request
 		return
 	}
 
+	if req.Method != http.MethodPost {
+		r.failRequest(ctx, resp, http.StatusBadRequest, invalidMethodRespBody, nil)
+		return
+	}
+
+	if req.Header.Get(httpContentTypeHeader) != protobufContentType {
+		r.failRequest(ctx, resp, http.StatusUnsupportedMediaType, invalidEventsContentRespBody, nil)
+		return
+	}
+
 	body, ok := r.readBody(ctx, resp, req)
 	if !ok {
 		return
@@ -336,6 +366,18 @@ func (r *sfxReceiver) failRequest(
 	)
 }
 
+func (r *sfxReceiver) addAccessTokenLabel(md pmetric.Metrics, req *http.Request) {
+	if r.config.AccessTokenPassthrough {
+		if accessToken := req.Header.Get(splunk.SFxAccessTokenHeader); accessToken != "" {
+			for i := 0; i < md.ResourceMetrics().Len(); i++ {
+				rm := md.ResourceMetrics().At(i)
+				res := rm.Resource()
+				res.Attributes().PutStr(splunk.SFxAccessTokenLabel, accessToken)
+			}
+		}
+	}
+}
+
 func initJSONResponse(s string) []byte {
 	respBody, err := json.Marshal(s)
 	if err != nil {