Add back copyTraceHeaders() as OpenTelemetry does not default propagate

pkg/api/echo.go

@@ -55,6 +55,9 @@ func (s *Server) echoHandler(w http.ResponseWriter, r *http.Request) {
 					return
 				}
 
+				// forward headers
+				copyTracingHeaders(r, backendReq)
+
 				backendReq.Header.Set("X-API-Version", version.VERSION)
 				backendReq.Header.Set("X-API-Revision", version.REVISION)
 
@@ -104,3 +107,22 @@ func (s *Server) echoHandler(w http.ResponseWriter, r *http.Request) {
 		w.Write(body)
 	}
 }
+
+func copyTracingHeaders(from *http.Request, to *http.Request) {
+	headers := []string{
+		"x-request-id",
+		"x-b3-traceid",
+		"x-b3-spanid",
+		"x-b3-parentspanid",
+		"x-b3-sampled",
+		"x-b3-flags",
+		"x-ot-span-context",
+	}
+
+	for i := range headers {
+		headerValue := from.Header.Get(headers[i])
+		if len(headerValue) > 0 {
+			to.Header.Set(headers[i], headerValue)
+		}
+	}
+}

pkg/api/mock.go

@@ -1,34 +1,34 @@
 package api
 
 import (
-  "go.opentelemetry.io/otel/trace"
-  "time"
+	"go.opentelemetry.io/otel/trace"
+	"time"
 
-  "github.com/gorilla/mux"
-  "go.uber.org/zap"
+	"github.com/gorilla/mux"
+	"go.uber.org/zap"
 )
 
 func NewMockServer() *Server {
-  config := &Config{
-    Port:                      "9898",
-    HttpServerShutdownTimeout: 5 * time.Second,
-    HttpServerTimeout:         30 * time.Second,
-    BackendURL:                []string{},
-    ConfigPath:                "/config",
-    DataPath:                  "/data",
-    HttpClientTimeout:         30 * time.Second,
-    UIColor:                   "blue",
-    UIPath:                    ".ui",
-    UIMessage:                 "Greetings",
-    Hostname:                  "localhost",
-  }
+	config := &Config{
+		Port:                      "9898",
+		HttpServerShutdownTimeout: 5 * time.Second,
+		HttpServerTimeout:         30 * time.Second,
+		BackendURL:                []string{},
+		ConfigPath:                "/config",
+		DataPath:                  "/data",
+		HttpClientTimeout:         30 * time.Second,
+		UIColor:                   "blue",
+		UIPath:                    ".ui",
+		UIMessage:                 "Greetings",
+		Hostname:                  "localhost",
+	}
 
-  logger, _ := zap.NewDevelopment()
+	logger, _ := zap.NewDevelopment()
 
-  return &Server{
-    router: mux.NewRouter(),
-    logger: logger,
-    config: config,
-    tracer: trace.NewNoopTracerProvider().Tracer("mock"),
-  }
+	return &Server{
+		router: mux.NewRouter(),
+		logger: logger,
+		config: config,
+		tracer: trace.NewNoopTracerProvider().Tracer("mock"),
+	}
 }