1 //
2 // Copyright 2015 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_SRC_CORE_LIB_SERVICE_CONFIG_SERVICE_CONFIG_IMPL_H
18 #define GRPC_SRC_CORE_LIB_SERVICE_CONFIG_SERVICE_CONFIG_IMPL_H
19 
20 #include <grpc/support/port_platform.h>
21 
22 #include <stddef.h>
23 
24 #include <memory>
25 #include <string>
26 #include <unordered_map>
27 #include <vector>
28 
29 #include "absl/status/statusor.h"
30 #include "absl/strings/string_view.h"
31 
32 #include <grpc/slice.h>
33 #include <grpc/support/log.h>
34 
35 #include "src/core/lib/channel/channel_args.h"
36 #include "src/core/lib/gprpp/ref_counted_ptr.h"
37 #include "src/core/lib/gprpp/validation_errors.h"
38 #include "src/core/lib/json/json.h"
39 #include "src/core/lib/service_config/service_config.h"
40 #include "src/core/lib/service_config/service_config_parser.h"
41 #include "src/core/lib/slice/slice_internal.h"
42 
43 // The main purpose of the code here is to parse the service config in
44 // JSON form, which will look like this:
45 //
46 // {
47 //   "loadBalancingPolicy": "string",  // optional
48 //   "methodConfig": [  // array of one or more method_config objects
49 //     {
50 //       "name": [  // array of one or more name objects
51 //         {
52 //           "service": "string",  // required
53 //           "method": "string",  // optional
54 //         }
55 //       ],
56 //       // remaining fields are optional.
57 //       // see https://developers.google.com/protocol-buffers/docs/proto3#json
58 //       // for format details.
59 //       "waitForReady": bool,
60 //       "timeout": "duration_string",
61 //       "maxRequestMessageBytes": "int64_string",
62 //       "maxResponseMessageBytes": "int64_string",
63 //     }
64 //   ]
65 // }
66 
67 namespace grpc_core {
68 
69 class ServiceConfigImpl final : public ServiceConfig {
70  public:
71   /// Creates a new service config from parsing \a json_string.
72   static absl::StatusOr<RefCountedPtr<ServiceConfig>> Create(
73       const ChannelArgs& args, absl::string_view json_string);
74 
75   // Alternate forms that are useful in edge cases.
76   static RefCountedPtr<ServiceConfig> Create(const ChannelArgs& args,
77                                              const Json& json,
78                                              absl::string_view json_string,
79                                              ValidationErrors* errors);
80   static RefCountedPtr<ServiceConfig> Create(const ChannelArgs& args,
81                                              const Json& json,
82                                              ValidationErrors* errors);
83 
84   ~ServiceConfigImpl() override;
85 
json_string()86   absl::string_view json_string() const override { return json_string_; }
87 
88   /// Retrieves the global parsed config at index \a index. The
89   /// lifetime of the returned object is tied to the lifetime of the
90   /// ServiceConfig object.
GetGlobalParsedConfig(size_t index)91   ServiceConfigParser::ParsedConfig* GetGlobalParsedConfig(
92       size_t index) override {
93     GPR_DEBUG_ASSERT(index < parsed_global_configs_.size());
94     return parsed_global_configs_[index].get();
95   }
96 
97   /// Retrieves the vector of parsed configs for the method identified
98   /// by \a path.  The lifetime of the returned vector and contained objects
99   /// is tied to the lifetime of the ServiceConfig object.
100   const ServiceConfigParser::ParsedConfigVector* GetMethodParsedConfigVector(
101       const grpc_slice& path) const override;
102 
103  private:
104   std::string json_string_;
105   Json json_;
106 
107   ServiceConfigParser::ParsedConfigVector parsed_global_configs_;
108   // A map from the method name to the parsed config vector. Note that we are
109   // using a raw pointer and not a unique pointer so that we can use the same
110   // vector for multiple names.
111   std::unordered_map<grpc_slice, const ServiceConfigParser::ParsedConfigVector*,
112                      SliceHash>
113       parsed_method_configs_map_;
114   // Default method config.
115   const ServiceConfigParser::ParsedConfigVector* default_method_config_vector_ =
116       nullptr;
117   // Storage for all the vectors that are being used in
118   // parsed_method_configs_map_ and default_method_config_vector_.
119   std::vector<ServiceConfigParser::ParsedConfigVector>
120       parsed_method_config_vectors_storage_;
121 };
122 
123 }  // namespace grpc_core
124 
125 #endif  // GRPC_SRC_CORE_LIB_SERVICE_CONFIG_SERVICE_CONFIG_IMPL_H
126