support stdlib request.GetBody

CHANGELOG.md

@@ -32,6 +32,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Fix bad log message when key-value pairs are dropped because of key duplication in `go.opentelemetry.io/otel/sdk/log`. (#7662)
 - Fix `DroppedAttributes` on `Record` in `go.opentelemetry.io/otel/sdk/log` to not count the non-attribute key-value pairs dropped because of key duplication. (#7662)
 - Fix `SetAttributes` on `Record` in `go.opentelemetry.io/otel/sdk/log` to not log that attributes are dropped when they are actually not dropped. (#7662)
+- Fix missing `request.GetBody` in `go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp` to correctly handle HTTP2 GOAWAY frame. (#7794)
 
 <!-- Released section -->
 <!-- Don't change this section unless doing release -->

exporters/otlp/otlptrace/otlptracehttp/client.go

@@ -270,6 +270,7 @@ func (d *client) newRequest(body []byte) (request, error) {
 	case NoCompression:
 		r.ContentLength = int64(len(body))
 		req.bodyReader = bodyReader(body)
+		req.GetBody = bodyReaderErr(body)
 	case GzipCompression:
 		// Ensure the content length is not used.
 		r.ContentLength = -1
@@ -290,6 +291,7 @@ func (d *client) newRequest(body []byte) (request, error) {
 		}
 
 		req.bodyReader = bodyReader(b.Bytes())
+		req.GetBody = bodyReaderErr(b.Bytes())
 	}
 
 	return req, nil
@@ -315,6 +317,13 @@ func bodyReader(buf []byte) func() io.ReadCloser {
 	}
 }
 
+// bodyReaderErr returns a closure returning a new reader for buf.
+func bodyReaderErr(buf []byte) func() (io.ReadCloser, error) {
+	return func() (io.ReadCloser, error) {
+		return io.NopCloser(bytes.NewReader(buf)), nil
+	}
+}
+
 // request wraps an http.Request with a resettable body reader.
 type request struct {
 	*http.Request

exporters/otlp/otlptrace/otlptracehttp/client_test.go

@@ -6,9 +6,12 @@ package otlptracehttp_test
 import (
 	"context"
 	"fmt"
+	"io"
 	"net/http"
+	"net/http/httptest"
 	"net/url"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -582,6 +585,59 @@ func TestClientInstrumentation(t *testing.T) {
 	metricdatatest.AssertEqual(t, want, got.ScopeMetrics[0], opt...)
 }
 
+func TestGetBodyCalledOnRedirect(t *testing.T) {
+	// Test that req.GetBody is set correctly, allowing the HTTP transport
+	// to re-send the body on 307 redirects.
+
+	var mu sync.Mutex
+	var requestBodies [][]byte
+
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		body, err := io.ReadAll(r.Body)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+		mu.Lock()
+		requestBodies = append(requestBodies, body)
+		isFirstRequest := len(requestBodies) == 1
+		mu.Unlock()
+
+		if isFirstRequest {
+			w.Header().Set("Location", "/v1/traces/final")
+			w.WriteHeader(http.StatusTemporaryRedirect)
+			return
+		}
+
+		w.Header().Set("Content-Type", "application/x-protobuf")
+		w.WriteHeader(http.StatusOK)
+	})
+
+	server := httptest.NewServer(handler)
+	defer server.Close()
+
+	client := otlptracehttp.NewClient(
+		otlptracehttp.WithEndpoint(server.Listener.Addr().String()),
+		otlptracehttp.WithInsecure(),
+	)
+
+	ctx := t.Context()
+	exporter, err := otlptrace.New(ctx, client)
+	require.NoError(t, err)
+	defer func() { _ = exporter.Shutdown(ctx) }()
+
+	err = exporter.ExportSpans(ctx, otlptracetest.SingleReadOnlySpan())
+	require.NoError(t, err)
+
+	mu.Lock()
+	defer mu.Unlock()
+
+	require.Len(t, requestBodies, 2, "expected 2 requests (original + redirect)")
+	assert.NotEmpty(t, requestBodies[0], "original request body should not be empty")
+	assert.Equal(t, requestBodies[0], requestBodies[1], "redirect body should match original")
+}
+
 func BenchmarkExporterExportSpans(b *testing.B) {
 	const n = 10