feat: Add ability to set adapter scoped metadata

go/adapter.go

@@ -21,6 +21,7 @@ type Adapter interface {
 type TraceEvent struct {
 	Events      []Event
 	TelemetryId TelemetryId
+	AdapterMeta interface{}
 }
 
 // Shared implementation for all Adapters

go/adapter/datadog/adapter.go

@@ -3,6 +3,7 @@ package datadog
 import (
 	"bytes"
 	"encoding/json"
+	"fmt"
 	"log"
 	"net/http"
 	"net/url"
@@ -75,9 +76,45 @@ func (d *DatadogAdapter) HandleTraceEvent(te observe.TraceEvent) {
 
 	go func() {
 		output := datadog_formatter.New()
-		// TODO: for the moment, these are hard-coded, but will transition to a programmer-
-		// controlled API to customer these values.
-		allSpans[0].Resource = "request"
+
+		if te.AdapterMeta != nil {
+			if meta, ok := te.AdapterMeta.(DatadogMetadata); ok {
+				topSpan := allSpans[0]
+				if topSpan.Meta == nil {
+					topSpan.Meta = make(map[string]string)
+				}
+				if meta.ResourceName != nil {
+					topSpan.Resource = *meta.ResourceName
+				}
+				if meta.HttpUrl != nil {
+					topSpan.Meta["http.url"] = *meta.HttpUrl
+				}
+				if meta.HttpStatusCode != nil {
+					topSpan.Meta["http.status_code"] = fmt.Sprintf("%d", *meta.HttpStatusCode)
+				}
+				if meta.HttpClientIp != nil {
+					topSpan.Meta["http.client_ip"] = *meta.HttpClientIp
+				}
+				if meta.HttpRequestContentLength != nil {
+					topSpan.Meta["http.request.content_length"] = fmt.Sprintf("%d", *meta.HttpRequestContentLength)
+				}
+				if meta.HttpRequestContentLengthUncompressed != nil {
+					topSpan.Meta["http.request.content_length_uncompressed"] = fmt.Sprintf("%d", *meta.HttpRequestContentLengthUncompressed)
+				}
+				if meta.HttpResponseContentLength != nil {
+					topSpan.Meta["http.response.content_length"] = fmt.Sprintf("%d", *meta.HttpResponseContentLength)
+				}
+				if meta.HttpResponseContentLengthUncompressed != nil {
+					topSpan.Meta["http.response.content_length_uncompressed"] = fmt.Sprintf("%d", *meta.HttpResponseContentLengthUncompressed)
+				}
+				if meta.SpanKind != nil {
+					topSpan.Meta["span.kind"] = meta.SpanKind.String()
+				}
+			} else {
+				log.Println("The Datadog adapter was expecting a DatadogMetadata object on the trace")
+			}
+		}
+
 		tt := d.Config.TraceType.String()
 		allSpans[0].Type = &tt
 		output.AddTrace(allSpans)
@@ -126,6 +163,19 @@ func (d *DatadogAdapter) makeCallSpans(event observe.CallEvent, parentId *uint64
 	return spans
 }
 
+type DatadogMetadata struct {
+	HttpUrl                               *string
+	HttpMethod                            *string
+	HttpStatusCode                        *int
+	ResourceName                          *string
+	HttpClientIp                          *string
+	HttpRequestContentLength              *int
+	HttpRequestContentLengthUncompressed  *int
+	HttpResponseContentLength             *int
+	HttpResponseContentLengthUncompressed *int
+	SpanKind                              *DatadogSpanKind
+}
+
 type DatadogSpanKind int
 
 const (

go/bin/datadog/main.go

@@ -46,6 +46,24 @@ func main() {
 	}
 	defer m.Close(ctx)
 
+	// normally this metadata would be in your web-server framework
+	// or derived when you need them. we're just gonna initialize
+	// some example values here
+	resourceName := "my-resource"
+	httpUrl := "https://example.com/my-endpoint"
+	httpStatusCode := 200
+	spanKind := datadog.Server
+	clientIp := "66.210.227.34"
+
+	meta := datadog.DatadogMetadata{
+		ResourceName:   &resourceName,
+		HttpUrl:        &httpUrl,
+		HttpStatusCode: &httpStatusCode,
+		SpanKind:       &spanKind,
+		HttpClientIp:   &clientIp,
+	}
+	traceCtx.Metadata(meta)
+
 	traceCtx.Finish()
 
 	time.Sleep(time.Second * 2)

go/trace_ctx.go

@@ -34,6 +34,7 @@ type TraceCtx struct {
 	Config      *Config
 	names       map[uint32]string
 	telemetryId TelemetryId
+	adapterMeta interface{}
 }
 
 // Creates a new TraceCtx. Used internally by the Adapter. The user should create the trace context from the Adapter.
@@ -59,12 +60,17 @@ func newTraceCtx(ctx context.Context, adapter *AdapterBase, r wazero.Runtime, da
 	return traceCtx, nil
 }
 
+func (t *TraceCtx) Metadata(metadata interface{}) {
+	t.adapterMeta = metadata
+}
+
 // Finish() will stop the trace and send the
 // TraceEvent payload to the adapter
 func (t *TraceCtx) Finish() {
 	traceEvent := TraceEvent{
 		Events:      t.events,
 		TelemetryId: t.telemetryId,
+		AdapterMeta: t.adapterMeta,
 	}
 	t.adapter <- traceEvent
 	// clear the trace context