1 // 2 // Copyright 2016 gRPC authors. 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SERVICE_CONFIG_PARSER_H 18 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SERVICE_CONFIG_PARSER_H 19 20 #include <grpc/support/port_platform.h> 21 22 #include <memory> 23 24 #include "absl/container/inlined_vector.h" 25 26 #include <grpc/impl/codegen/grpc_types.h> 27 28 #include "src/core/lib/iomgr/error.h" 29 #include "src/core/lib/json/json.h" 30 31 namespace grpc_core { 32 33 // Service config parser registry. 34 // See service_config.h for more information. 35 class ServiceConfigParser { 36 public: 37 /// This is the base class that all service config parsers MUST use to store 38 /// parsed service config data. 39 class ParsedConfig { 40 public: 41 virtual ~ParsedConfig() = default; 42 }; 43 44 /// This is the base class that all service config parsers should derive from. 45 class Parser { 46 public: 47 virtual ~Parser() = default; 48 ParseGlobalParams(const grpc_channel_args *,const Json &,grpc_error_handle * error)49 virtual std::unique_ptr<ParsedConfig> ParseGlobalParams( 50 const grpc_channel_args*, const Json& /* json */, 51 grpc_error_handle* error) { 52 // Avoid unused parameter warning on debug-only parameter 53 (void)error; 54 GPR_DEBUG_ASSERT(error != nullptr); 55 return nullptr; 56 } 57 ParsePerMethodParams(const grpc_channel_args *,const Json &,grpc_error_handle * error)58 virtual std::unique_ptr<ParsedConfig> ParsePerMethodParams( 59 const grpc_channel_args*, const Json& /* json */, 60 grpc_error_handle* error) { 61 // Avoid unused parameter warning on debug-only parameter 62 (void)error; 63 GPR_DEBUG_ASSERT(error != nullptr); 64 return nullptr; 65 } 66 }; 67 68 static constexpr int kNumPreallocatedParsers = 4; 69 typedef absl::InlinedVector<std::unique_ptr<ParsedConfig>, 70 kNumPreallocatedParsers> 71 ParsedConfigVector; 72 73 static void Init(); 74 static void Shutdown(); 75 76 /// Globally register a service config parser. On successful registration, it 77 /// returns the index at which the parser was registered. On failure, -1 is 78 /// returned. Each new service config update will go through all the 79 /// registered parser. Each parser is responsible for reading the service 80 /// config json and returning a parsed config. This parsed config can later be 81 /// retrieved using the same index that was returned at registration time. 82 static size_t RegisterParser(std::unique_ptr<Parser> parser); 83 84 static ParsedConfigVector ParseGlobalParameters(const grpc_channel_args* args, 85 const Json& json, 86 grpc_error_handle* error); 87 88 static ParsedConfigVector ParsePerMethodParameters( 89 const grpc_channel_args* args, const Json& json, 90 grpc_error_handle* error); 91 }; 92 93 } // namespace grpc_core 94 95 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SERVICE_CONFIG_PARSER_H */ 96