fix(go): propagate traceparent without respecting CORS (#800)

Co-authored-by: Josh Hunt <[email protected]>

Author: Proximyst

pkg/service/browser.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"log/slog"
 	"maps"
+	"net/http"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -19,7 +20,9 @@ import (
 	"time"
 
 	"github.com/chromedp/cdproto/browser"
+	"github.com/chromedp/cdproto/cdp"
 	"github.com/chromedp/cdproto/emulation"
+	"github.com/chromedp/cdproto/fetch"
 	"github.com/chromedp/cdproto/network"
 	"github.com/chromedp/cdproto/page"
 	"github.com/chromedp/chromedp"
@@ -233,6 +236,7 @@ func (s *BrowserService) Render(ctx context.Context, url string, printer Printer
 	fileChan := make(chan []byte, 1) // buffered: we don't want the browser to stick around while we try to export this value.
 	actions := []chromedp.Action{
 		tracingAction("network.Enable", network.Enable()),
+		tracingAction("fetch.Enable", fetch.Enable()), // required by handleNetworkEvents
 		tracingAction("SetPageScaleFactor", emulation.SetPageScaleFactor(cfg.PageScaleFactor)),
 		tracingAction("EmulateViewport", chromedp.EmulateViewport(int64(cfg.MinWidth), int64(cfg.MinHeight), orientation)),
 		setHeaders(browserCtx, cfg.Headers),
@@ -392,6 +396,34 @@ func (s *BrowserService) handleNetworkEvents(browserCtx context.Context) {
 		// See the docs of ListenTarget for more.
 
 		switch e := ev.(type) {
+		case *fetch.EventRequestPaused:
+			go func() {
+				if sc := trace.SpanFromContext(browserCtx); sc != nil && sc.IsRecording() {
+					otel.GetTextMapPropagator().Inject(browserCtx, networkHeadersCarrier(e.Request.Headers))
+				}
+
+				hdrs := make([]*fetch.HeaderEntry, 0, len(e.Request.Headers))
+				for k, v := range e.Request.Headers {
+					hdrs = append(hdrs, &fetch.HeaderEntry{Name: k, Value: fmt.Sprintf("%v", v)})
+				}
+
+				ctx, span := tracer.Start(browserCtx, "fetch.ContinueRequest",
+					trace.WithAttributes(
+						attribute.String("requestID", string(e.RequestID)),
+						attribute.String("url", e.Request.URL),
+						attribute.String("method", e.Request.Method),
+						attribute.Int("headers", len(e.Request.Headers)),
+					))
+				defer span.End()
+				cdpCtx := chromedp.FromContext(browserCtx)
+				ctx = cdp.WithExecutor(ctx, cdpCtx.Target)
+
+				if err := fetch.ContinueRequest(e.RequestID).WithHeaders(hdrs).Do(ctx); err != nil {
+					span.SetStatus(codes.Error, err.Error())
+					slog.DebugContext(ctx, "failed to continue request", "requestID", e.RequestID, "error", err)
+				}
+			}()
+
 		case *network.EventRequestWillBeSent:
 			mu.Lock()
 			defer mu.Unlock()
@@ -414,17 +446,20 @@ func (s *BrowserService) handleNetworkEvents(browserCtx context.Context) {
 			if !ok {
 				return
 			}
+			statusText := e.Response.StatusText
+			if statusText == "" {
+				statusText = http.StatusText(int(e.Response.Status))
+			}
 			span.SetAttributes(
 				attribute.Int("status", int(e.Response.Status)),
-				attribute.String("statusText", e.Response.StatusText),
+				attribute.String("statusText", statusText),
 				attribute.String("mimeType", e.Response.MimeType),
 				attribute.String("protocol", e.Response.Protocol),
-				attribute.String("contentType", fmt.Sprintf("%v", e.Response.Headers["Content-Type"])),
 			)
 			if e.Response.Status >= 400 {
-				span.SetStatus(codes.Error, e.Response.StatusText)
+				span.SetStatus(codes.Error, fmt.Sprintf("%d %s", e.Response.Status, statusText))
 			} else {
-				span.SetStatus(codes.Ok, e.Response.StatusText)
+				span.SetStatus(codes.Ok, fmt.Sprintf("%d %s", e.Response.Status, statusText))
 			}
 			span.End(trace.WithTimestamp(e.Timestamp.Time()))
 			delete(requests, e.RequestID) // no point keeping it around anymore.
@@ -751,13 +786,6 @@ func NewPNGPrinter(opts ...PNGPrinterOption) (*pngPrinter, error) {
 }
 
 func setHeaders(browserCtx context.Context, headers network.Headers) chromedp.Action {
-	if sc := trace.SpanFromContext(browserCtx); sc != nil && sc.IsRecording() {
-		if headers == nil {
-			headers = make(network.Headers)
-		}
-		otel.GetTextMapPropagator().Inject(browserCtx, networkHeadersCarrier(headers))
-	}
-
 	return chromedp.ActionFunc(func(ctx context.Context) error {
 		tracer := tracer(ctx)
 		ctx, span := tracer.Start(ctx, "setHeaders",