transcoding: Teach transcoding filter to be aware of per vhost / per route settings

api/envoy/extensions/filters/http/grpc_json_transcoder/v3/transcoder.proto

@@ -16,6 +16,14 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 // [#extension: envoy.filters.http.grpc_json_transcoder]
 
 // [#next-free-field: 11]
+// GrpcJsonTranscoder filter configuration.
+// The filter itself can be used per route / per virtual host or on the general level. The most
+// specific one is being used for a given route. If the list of services is empty - filter
+// is considered to be disabled.
+// Note that if specifying the filter per route, first the route is matched, and then transcoding
+// filter is applied. It matters when specifying the route configuration and paths to match the
+// request - for per-route grpc transcoder configs, the original path should be matched, while
+// in other cases, the grpc-like path is expected (the one AFTER the filter is applied).
 message GrpcJsonTranscoder {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.config.filter.http.transcoder.v2.GrpcJsonTranscoder";
@@ -80,7 +88,8 @@ message GrpcJsonTranscoder {
   // the transcoder will translate. If the service name doesn't exist in ``proto_descriptor``,
   // Envoy will fail at startup. The ``proto_descriptor`` may contain more services than
   // the service names specified here, but they won't be translated.
-  repeated string services = 2 [(validate.rules).repeated = {min_items: 1}];
+  // If the list of services is empty, filter is considered disabled.
+  repeated string services = 2;
 
   // Control options for response JSON. These options are passed directly to
   // `JsonPrintOptions <https://developers.google.com/protocol-buffers/docs/reference/cpp/

docs/root/version_history/current.rst

@@ -54,6 +54,7 @@ New Features
 * access log: added the :ref:`formatters <envoy_v3_api_field_config.core.v3.SubstitutionFormatString.formatters>` extension point for custom formatters (command operators).
 * access log: support command operator: %REQUEST_HEADERS_BYTES%, %RESPONSE_HEADERS_BYTES% and %RESPONSE_TRAILERS_BYTES%.
 * dispatcher: supports a stack of `Envoy::ScopeTrackedObject` instead of a single tracked object. This will allow Envoy to dump more debug information on crash.
+* grpc_json_transcoder: filter can now be configured on per-route/per-vhost level as well. Leaving empty list of services in the filter configuration disables transcoding on the specific route.
 * http: added support for :ref:`:ref:`preconnecting <envoy_v3_api_msg_config.cluster.v3.Cluster.PreconnectPolicy>`. Preconnecting is off by default, but recommended for clusters serving latency-sensitive traffic, especially if using HTTP/1.1.
 * http: change frame flood and abuse checks to the upstream HTTP/2 codec to ON by default. It can be disabled by setting the `envoy.reloadable_features.upstream_http2_flood_checks` runtime key to false.
 * overload: add support for scaling :ref:`transport connection timeouts<envoy_v3_api_enum_value_config.overload.v3.ScaleTimersOverloadActionConfig.TimerType.TRANSPORT_SOCKET_CONNECT>`. This can be used to reduce the TLS handshake timeout in response to overload.

source/extensions/filters/http/grpc_json_transcoder/BUILD

@@ -30,6 +30,7 @@ envoy_cc_library(
         "//source/common/grpc:common_lib",
         "//source/common/http:headers_lib",
         "//source/common/protobuf",
+        "//source/extensions/filters/http:well_known_names",
         "@envoy_api//envoy/extensions/filters/http/grpc_json_transcoder/v3:pkg_cc_proto",
     ],
 )

source/extensions/filters/http/grpc_json_transcoder/config.cc

@@ -23,6 +23,15 @@ Http::FilterFactoryCb GrpcJsonTranscoderFilterConfig::createFilterFactoryFromPro
   };
 }
 
+Router::RouteSpecificFilterConfigConstSharedPtr
+GrpcJsonTranscoderFilterConfig::createRouteSpecificFilterConfigTyped(
+    const envoy::extensions::filters::http::grpc_json_transcoder::v3::GrpcJsonTranscoder&
+        proto_config,
+    Server::Configuration::ServerFactoryContext& context, ProtobufMessage::ValidationVisitor&) {
+
+  return std::make_shared<JsonTranscoderConfig>(proto_config, context.api());
+}
+
 /**
  * Static registration for the grpc transcoding filter. @see RegisterNamedHttpFilterConfigFactory.
  */

source/extensions/filters/http/grpc_json_transcoder/config.h

@@ -25,6 +25,11 @@ class GrpcJsonTranscoderFilterConfig
       const envoy::extensions::filters::http::grpc_json_transcoder::v3::GrpcJsonTranscoder&
           proto_config,
       const std::string& stats_prefix, Server::Configuration::FactoryContext& context) override;
+
+  Router::RouteSpecificFilterConfigConstSharedPtr createRouteSpecificFilterConfigTyped(
+      const envoy::extensions::filters::http::grpc_json_transcoder::v3::GrpcJsonTranscoder&,
+      Server::Configuration::ServerFactoryContext& context,
+      ProtobufMessage::ValidationVisitor& validator) override;
 };
 
 } // namespace GrpcJsonTranscoder

source/extensions/filters/http/grpc_json_transcoder/json_transcoder_filter.cc

@@ -17,6 +17,7 @@
 #include "common/protobuf/utility.h"
 
 #include "extensions/filters/http/grpc_json_transcoder/http_body_utils.h"
+#include "extensions/filters/http/well_known_names.h"
 
 #include "google/api/annotations.pb.h"
 #include "google/api/http.pb.h"
@@ -111,6 +112,12 @@ JsonTranscoderConfig::JsonTranscoderConfig(
     const envoy::extensions::filters::http::grpc_json_transcoder::v3::GrpcJsonTranscoder&
         proto_config,
     Api::Api& api) {
+
+  disabled_ = proto_config.services().empty();
+  if (disabled_) {
+    return;
+  }
+
   FileDescriptorSet descriptor_set;
 
   switch (proto_config.descriptor_set_case()) {
@@ -306,8 +313,11 @@ bool JsonTranscoderConfig::convertGrpcStatus() const { return convert_grpc_statu
 
 ProtobufUtil::Status JsonTranscoderConfig::createTranscoder(
     const Http::RequestHeaderMap& headers, ZeroCopyInputStream& request_input,
-    google::grpc::transcoding::TranscoderInputStream& response_input, TranscoderPtr& transcoder,
-    MethodInfoSharedPtr& method_info) {
+    google::grpc::transcoding::TranscoderInputStream& response_input,
+    std::unique_ptr<Transcoder>& transcoder, MethodInfoSharedPtr& method_info) const {
+
+  ASSERT(!disabled_);
+
   if (Grpc::Common::isGrpcRequestHeaders(headers)) {
     return ProtobufUtil::Status(Code::INVALID_ARGUMENT,
                                 "Request headers has application/grpc content-type");
@@ -384,7 +394,7 @@ ProtobufUtil::Status JsonTranscoderConfig::createTranscoder(
 
 ProtobufUtil::Status
 JsonTranscoderConfig::methodToRequestInfo(const MethodInfoSharedPtr& method_info,
-                                          google::grpc::transcoding::RequestInfo* info) {
+                                          google::grpc::transcoding::RequestInfo* info) const {
   const std::string& request_type_full_name = method_info->descriptor_->input_type()->full_name();
   auto request_type_url = Grpc::Common::typeUrl(request_type_full_name);
   info->message_type = type_helper_->Info()->GetTypeByTypeUrl(request_type_url);
@@ -399,18 +409,37 @@ JsonTranscoderConfig::methodToRequestInfo(const MethodInfoSharedPtr& method_info
 
 ProtobufUtil::Status
 JsonTranscoderConfig::translateProtoMessageToJson(const Protobuf::Message& message,
-                                                  std::string* json_out) {
+                                                  std::string* json_out) const {
   return ProtobufUtil::BinaryToJsonString(
       type_helper_->Resolver(), Grpc::Common::typeUrl(message.GetDescriptor()->full_name()),
       message.SerializeAsString(), json_out, print_options_);
 }
 
 JsonTranscoderFilter::JsonTranscoderFilter(JsonTranscoderConfig& config) : config_(config) {}
 
+void JsonTranscoderFilter::initPerRouteConfig() {
+  if (!decoder_callbacks_->route() || !decoder_callbacks_->route()->routeEntry()) {
+    per_route_config_ = &config_;
+    return;
+  }
+
+  const std::string& name = HttpFilterNames::get().GrpcJsonTranscoder;
+  const auto* entry = decoder_callbacks_->route()->routeEntry();
+  const auto* route_local = entry->mostSpecificPerFilterConfigTyped<JsonTranscoderConfig>(name);
+
+  per_route_config_ = route_local ? route_local : &config_;
+}
+
 Http::FilterHeadersStatus JsonTranscoderFilter::decodeHeaders(Http::RequestHeaderMap& headers,
                                                               bool end_stream) {
+
+  initPerRouteConfig();
+  if (per_route_config_->disabled()) {
+    return Http::FilterHeadersStatus::Continue;
+  }
+
   const auto status =
-      config_.createTranscoder(headers, request_in_, response_in_, transcoder_, method_);
+      per_route_config_->createTranscoder(headers, request_in_, response_in_, transcoder_, method_);
 
   if (!status.ok()) {
     // If transcoder couldn't be created, it might be a normal gRPC request, so the filter will
@@ -449,7 +478,7 @@ Http::FilterHeadersStatus JsonTranscoderFilter::decodeHeaders(Http::RequestHeade
   headers.setReferenceMethod(Http::Headers::get().MethodValues.Post);
   headers.setReferenceTE(Http::Headers::get().TEValues.Trailers);
 
-  if (!config_.matchIncomingRequestInfo()) {
+  if (!per_route_config_->matchIncomingRequestInfo()) {
     decoder_callbacks_->clearRouteCache();
   }
 
@@ -611,7 +640,7 @@ JsonTranscoderFilter::encodeTrailers(Http::ResponseTrailerMap& trailers) {
 }
 
 void JsonTranscoderFilter::doTrailers(Http::ResponseHeaderOrTrailerMap& headers_or_trailers) {
-  if (error_ || !transcoder_) {
+  if (error_ || !transcoder_ || !per_route_config_ || per_route_config_->disabled()) {
     return;
   }
 
@@ -767,7 +796,8 @@ bool JsonTranscoderFilter::buildResponseFromHttpBodyOutput(
 
 bool JsonTranscoderFilter::maybeConvertGrpcStatus(Grpc::Status::GrpcStatus grpc_status,
                                                   Http::ResponseHeaderOrTrailerMap& trailers) {
-  if (!config_.convertGrpcStatus()) {
+  ASSERT(per_route_config_ && !per_route_config_->disabled());
+  if (!per_route_config_->convertGrpcStatus()) {
     return false;
   }
 
@@ -799,7 +829,8 @@ bool JsonTranscoderFilter::maybeConvertGrpcStatus(Grpc::Status::GrpcStatus grpc_
   }
 
   std::string json_status;
-  auto translate_status = config_.translateProtoMessageToJson(*status_details, &json_status);
+  auto translate_status =
+      per_route_config_->translateProtoMessageToJson(*status_details, &json_status);
   if (!translate_status.ok()) {
     ENVOY_LOG(debug, "Transcoding status error {}", translate_status.ToString());
     return false;

source/extensions/filters/http/grpc_json_transcoder/json_transcoder_filter.h

@@ -56,7 +56,9 @@ void createHttpBodyEnvelope(Buffer::Instance& output,
 /**
  * Global configuration for the gRPC JSON transcoder filter. Factory for the Transcoder interface.
  */
-class JsonTranscoderConfig : public Logger::Loggable<Logger::Id::config> {
+class JsonTranscoderConfig : public Logger::Loggable<Logger::Id::config>,
+                             public Router::RouteSpecificFilterConfig {
+
 public:
   /**
    * constructor that loads protobuf descriptors from the file specified in the JSON config.
@@ -81,13 +83,13 @@ class JsonTranscoderConfig : public Logger::Loggable<Logger::Id::config> {
                    Protobuf::io::ZeroCopyInputStream& request_input,
                    google::grpc::transcoding::TranscoderInputStream& response_input,
                    std::unique_ptr<google::grpc::transcoding::Transcoder>& transcoder,
-                   MethodInfoSharedPtr& method_info);
+                   MethodInfoSharedPtr& method_info) const;
 
   /**
    * Converts an arbitrary protobuf message to JSON.
    */
   ProtobufUtil::Status translateProtoMessageToJson(const Protobuf::Message& message,
-                                                   std::string* json_out);
+                                                   std::string* json_out) const;
 
   /**
    * If true, skip clearing the route cache after the incoming request has been modified.
@@ -102,12 +104,14 @@ class JsonTranscoderConfig : public Logger::Loggable<Logger::Id::config> {
    */
   bool convertGrpcStatus() const;
 
+  bool disabled() const { return disabled_; }
+
 private:
   /**
    * Convert method descriptor to RequestInfo that needed for transcoding library
    */
   ProtobufUtil::Status methodToRequestInfo(const MethodInfoSharedPtr& method_info,
-                                           google::grpc::transcoding::RequestInfo* info);
+                                           google::grpc::transcoding::RequestInfo* info) const;
 
 private:
   void addFileDescriptor(const Protobuf::FileDescriptorProto& file);
@@ -128,6 +132,8 @@ class JsonTranscoderConfig : public Logger::Loggable<Logger::Id::config> {
   bool match_incoming_request_route_{false};
   bool ignore_unknown_query_parameters_{false};
   bool convert_grpc_status_{false};
+
+  bool disabled_;
 };
 
 using JsonTranscoderConfigSharedPtr = std::shared_ptr<JsonTranscoderConfig>;
@@ -176,15 +182,17 @@ class JsonTranscoderFilter : public Http::StreamFilter, public Logger::Loggable<
                               Http::ResponseHeaderOrTrailerMap& trailers);
   bool hasHttpBodyAsOutputType();
   void doTrailers(Http::ResponseHeaderOrTrailerMap& headers_or_trailers);
+  void initPerRouteConfig();
 
   JsonTranscoderConfig& config_;
+  const JsonTranscoderConfig* per_route_config_{};
   std::unique_ptr<google::grpc::transcoding::Transcoder> transcoder_;
   TranscoderInputStreamImpl request_in_;
   TranscoderInputStreamImpl response_in_;
-  Http::StreamDecoderFilterCallbacks* decoder_callbacks_{nullptr};
-  Http::StreamEncoderFilterCallbacks* encoder_callbacks_{nullptr};
+  Http::StreamDecoderFilterCallbacks* decoder_callbacks_{};
+  Http::StreamEncoderFilterCallbacks* encoder_callbacks_{};
   MethodInfoSharedPtr method_;
-  Http::ResponseHeaderMap* response_headers_{nullptr};
+  Http::ResponseHeaderMap* response_headers_{};
   Grpc::Decoder decoder_;
 
   // Data of the initial request message, initialized from query arguments, path, etc.

test/extensions/filters/http/grpc_json_transcoder/BUILD

@@ -67,6 +67,7 @@ envoy_extension_cc_test(
         "//test/integration:http_integration_lib",
         "//test/proto:bookstore_proto_cc_proto",
         "//test/test_common:utility_lib",
+        "@envoy_api//envoy/extensions/filters/http/grpc_json_transcoder/v3:pkg_cc_proto",
     ],
 )