Create a child span for mixer check call

src/envoy/http/mixer/control.cc

@@ -42,8 +42,8 @@ Control::Control(const Config& config, Upstream::ClusterManager& cm,
 }
 
 Utils::CheckTransport::Func Control::GetCheckTransport(
-    const HeaderMap* headers) {
-  return Utils::CheckTransport::GetFunc(*check_client_factory_, headers);
+    Tracing::Span& parent_span) {
+  return Utils::CheckTransport::GetFunc(*check_client_factory_, parent_span);
 }
 
 // Call controller to get statistics.

src/envoy/http/mixer/control.h

@@ -41,7 +41,7 @@ class Control final : public ThreadLocal::ThreadLocalObject {
   ::istio::control::http::Controller* controller() { return controller_.get(); }
 
   // Create a per-request Check transport function.
-  Utils::CheckTransport::Func GetCheckTransport(const HeaderMap* headers);
+  Utils::CheckTransport::Func GetCheckTransport(Tracing::Span& parent_span);
 
  private:
   // Call controller to get statistics.

src/envoy/http/mixer/filter.cc

@@ -133,7 +133,8 @@ FilterHeadersStatus Filter::decodeHeaders(HeaderMap& headers, bool) {
   HeaderUpdate header_update(&headers);
   headers_ = &headers;
   cancel_check_ = handler_->Check(
-      &check_data, &header_update, control_.GetCheckTransport(&headers),
+      &check_data, &header_update,
+      control_.GetCheckTransport(decoder_callbacks_->activeSpan()),
       [this](const Status& status) { completeCheck(status); });
   initiating_call_ = false;
 

src/envoy/utils/grpc_transport.cc

@@ -25,59 +25,23 @@ namespace {
 // gRPC request timeout
 const std::chrono::milliseconds kGrpcRequestTimeoutMs(5000);
 
-// HTTP trace headers that should pass to gRPC metadata from origin request.
-// x-request-id is added for easy debugging.
-const Http::LowerCaseString kRequestId("x-request-id");
-const Http::LowerCaseString kB3TraceId("x-b3-traceid");
-const Http::LowerCaseString kB3SpanId("x-b3-spanid");
-const Http::LowerCaseString kB3ParentSpanId("x-b3-parentspanid");
-const Http::LowerCaseString kB3Sampled("x-b3-sampled");
-const Http::LowerCaseString kB3Flags("x-b3-flags");
-const Http::LowerCaseString kOtSpanContext("x-ot-span-context");
-
-inline void CopyHeaderEntry(const Http::HeaderEntry *entry,
-                            const Http::LowerCaseString &key,
-                            Http::HeaderMap &headers) {
-  if (entry) {
-    std::string val(entry->value().c_str(), entry->value().size());
-    headers.addReferenceKey(key, val);
-  }
-}
-
 }  // namespace
 
 template <class RequestType, class ResponseType>
 GrpcTransport<RequestType, ResponseType>::GrpcTransport(
     Grpc::AsyncClientPtr async_client, const RequestType &request,
-    const Http::HeaderMap *headers, ResponseType *response,
+    ResponseType *response, Tracing::Span &parent_span,
     istio::mixerclient::DoneFunc on_done)
     : async_client_(std::move(async_client)),
-      headers_(headers),
       response_(response),
       on_done_(on_done),
       request_(async_client_->send(
-          descriptor(), request, *this, Tracing::NullSpan::instance(),
+          descriptor(), request, *this, parent_span,
           absl::optional<std::chrono::milliseconds>(kGrpcRequestTimeoutMs))) {
   ENVOY_LOG(debug, "Sending {} request: {}", descriptor().name(),
             request.DebugString());
 }
 
-template <class RequestType, class ResponseType>
-void GrpcTransport<RequestType, ResponseType>::onCreateInitialMetadata(
-    Http::HeaderMap &metadata) {
-  if (!headers_) return;
-
-  CopyHeaderEntry(headers_->RequestId(), kRequestId, metadata);
-  CopyHeaderEntry(headers_->XB3TraceId(), kB3TraceId, metadata);
-  CopyHeaderEntry(headers_->XB3SpanId(), kB3SpanId, metadata);
-  CopyHeaderEntry(headers_->XB3ParentSpanId(), kB3ParentSpanId, metadata);
-  CopyHeaderEntry(headers_->XB3Sampled(), kB3Sampled, metadata);
-  CopyHeaderEntry(headers_->XB3Flags(), kB3Flags, metadata);
-
-  // This one is NOT inline, need to do linar search.
-  CopyHeaderEntry(headers_->get(kOtSpanContext), kOtSpanContext, metadata);
-}
-
 template <class RequestType, class ResponseType>
 void GrpcTransport<RequestType, ResponseType>::onSuccess(
     std::unique_ptr<ResponseType> &&response, Tracing::Span &) {
@@ -107,12 +71,13 @@ void GrpcTransport<RequestType, ResponseType>::Cancel() {
 template <class RequestType, class ResponseType>
 typename GrpcTransport<RequestType, ResponseType>::Func
 GrpcTransport<RequestType, ResponseType>::GetFunc(
-    Grpc::AsyncClientFactory &factory, const Http::HeaderMap *headers) {
-  return [&factory, headers](const RequestType &request, ResponseType *response,
-                             istio::mixerclient::DoneFunc on_done)
+    Grpc::AsyncClientFactory &factory, Tracing::Span &parent_span) {
+  return [&factory, &parent_span](const RequestType &request,
+                                  ResponseType *response,
+                                  istio::mixerclient::DoneFunc on_done)
              -> istio::mixerclient::CancelFunc {
     auto transport = new GrpcTransport<RequestType, ResponseType>(
-        factory.create(), request, headers, response, on_done);
+        factory.create(), request, response, parent_span, on_done);
     return [transport]() { transport->Cancel(); };
   };
 }
@@ -137,9 +102,9 @@ const google::protobuf::MethodDescriptor &ReportTransport::descriptor() {
 
 // explicitly instantiate CheckTransport and ReportTransport
 template CheckTransport::Func CheckTransport::GetFunc(
-    Grpc::AsyncClientFactory &factory, const Http::HeaderMap *headers);
+    Grpc::AsyncClientFactory &factory, Tracing::Span &parent_span);
 template ReportTransport::Func ReportTransport::GetFunc(
-    Grpc::AsyncClientFactory &factory, const Http::HeaderMap *headers);
+    Grpc::AsyncClientFactory &factory, Tracing::Span &parent_span);
 
 }  // namespace Utils
 }  // namespace Envoy

src/envoy/utils/grpc_transport.h

@@ -39,14 +39,13 @@ class GrpcTransport : public Grpc::TypedAsyncRequestCallbacks<ResponseType>,
       istio::mixerclient::DoneFunc on_done)>;
 
   static Func GetFunc(Grpc::AsyncClientFactory& factory,
-                      const Http::HeaderMap* headers = nullptr);
+                      Tracing::Span& parent_span);
 
   GrpcTransport(Grpc::AsyncClientPtr async_client, const RequestType& request,
-                const Http::HeaderMap* headers, ResponseType* response,
+                ResponseType* response, Tracing::Span& parent_span,
                 istio::mixerclient::DoneFunc on_done);
 
-  // Grpc::AsyncRequestCallbacks<ResponseType>
-  void onCreateInitialMetadata(Http::HeaderMap& metadata) override;
+  void onCreateInitialMetadata(Http::HeaderMap&) override {}
 
   void onSuccess(std::unique_ptr<ResponseType>&& response,
                  Tracing::Span& span) override;
@@ -60,7 +59,6 @@ class GrpcTransport : public Grpc::TypedAsyncRequestCallbacks<ResponseType>,
   static const google::protobuf::MethodDescriptor& descriptor();
 
   Grpc::AsyncClientPtr async_client_;
-  const Http::HeaderMap* headers_;
   ResponseType* response_;
   ::istio::mixerclient::DoneFunc on_done_;
   Grpc::AsyncRequest* request_{};

src/envoy/utils/mixer_control.cc

@@ -61,8 +61,10 @@ void CreateEnvironment(Event::Dispatcher &dispatcher,
                        Grpc::AsyncClientFactory &check_client_factory,
                        Grpc::AsyncClientFactory &report_client_factory,
                        ::istio::mixerclient::Environment *env) {
-  env->check_transport = CheckTransport::GetFunc(check_client_factory, nullptr);
-  env->report_transport = ReportTransport::GetFunc(report_client_factory);
+  env->check_transport = CheckTransport::GetFunc(check_client_factory,
+                                                 Tracing::NullSpan::instance());
+  env->report_transport = ReportTransport::GetFunc(
+      report_client_factory, Tracing::NullSpan::instance());
 
   env->timer_create_func = [&dispatcher](std::function<void()> timer_cb)
       -> std::unique_ptr<::istio::mixerclient::Timer> {