1 // Copyright 2024 gRPC authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef GRPC_SRC_CORE_CLIENT_CHANNEL_LB_METADATA_H 16 #define GRPC_SRC_CORE_CLIENT_CHANNEL_LB_METADATA_H 17 18 #include <grpc/event_engine/slice.h> 19 20 #include <string> 21 #include <vector> 22 23 #include "absl/strings/string_view.h" 24 #include "absl/types/optional.h" 25 #include "src/core/lib/transport/metadata_batch.h" 26 #include "src/core/load_balancing/lb_policy.h" 27 28 namespace grpc_core { 29 30 class LbMetadata : public LoadBalancingPolicy::MetadataInterface { 31 public: LbMetadata(grpc_metadata_batch * batch)32 explicit LbMetadata(grpc_metadata_batch* batch) : batch_(batch) {} 33 34 absl::optional<absl::string_view> Lookup(absl::string_view key, 35 std::string* buffer) const override; 36 37 std::vector<std::pair<std::string, std::string>> TestOnlyCopyToVector() const; 38 39 private: 40 grpc_metadata_batch* batch_; 41 }; 42 43 class MetadataMutationHandler { 44 public: 45 static void Apply(LoadBalancingPolicy::MetadataMutations& metadata_mutations, 46 grpc_metadata_batch* metadata); 47 }; 48 49 void MaybeOverrideAuthority( 50 grpc_event_engine::experimental::Slice authority_override, 51 grpc_metadata_batch* metadata); 52 53 } // namespace grpc_core 54 55 #endif // GRPC_SRC_CORE_CLIENT_CHANNEL_LB_METADATA_H 56