diff options
Diffstat (limited to 'src/core/lib/transport/service_config.h')
-rw-r--r-- | src/core/lib/transport/service_config.h | 256 |
1 files changed, 221 insertions, 35 deletions
diff --git a/src/core/lib/transport/service_config.h b/src/core/lib/transport/service_config.h index 6517f36802..a65b267d46 100644 --- a/src/core/lib/transport/service_config.h +++ b/src/core/lib/transport/service_config.h @@ -20,44 +20,230 @@ #include <grpc/support/port_platform.h> #include <grpc/impl/codegen/grpc_types.h> +#include <grpc/support/string_util.h> +#include "src/core/lib/gprpp/inlined_vector.h" +#include "src/core/lib/gprpp/ref_counted_ptr.h" #include "src/core/lib/json/json.h" #include "src/core/lib/slice/slice_hash_table.h" -typedef struct grpc_service_config grpc_service_config; - -grpc_service_config* grpc_service_config_create(const char* json_string); -void grpc_service_config_destroy(grpc_service_config* service_config); - -/// Invokes \a process_json() for each global parameter in the service -/// config. \a arg is passed as the second argument to \a process_json(). -void grpc_service_config_parse_global_params( - const grpc_service_config* service_config, - void (*process_json)(const grpc_json* json, void* arg), void* arg); - -/// Gets the LB policy name from \a service_config. -/// Returns NULL if no LB policy name was specified. -/// Caller does NOT take ownership. -const char* grpc_service_config_get_lb_policy_name( - const grpc_service_config* service_config); - -/// Creates a method config table based on the data in \a json. -/// The table's keys are request paths. The table's value type is -/// returned by \a create_value(), based on data parsed from the JSON tree. -/// \a ref_value() and \a unref_value() are used to ref and unref values. -/// Returns NULL on error. -grpc_slice_hash_table* grpc_service_config_create_method_config_table( - const grpc_service_config* service_config, - void* (*create_value)(const grpc_json* method_config_json), - void* (*ref_value)(void* value), void (*unref_value)(void* value)); - -/// A helper function for looking up values in the table returned by -/// \a grpc_service_config_create_method_config_table(). -/// Gets the method config for the specified \a path, which should be of -/// the form "/service/method". -/// Returns NULL if the method has no config. -/// Caller does NOT own a reference to the result. -void* grpc_method_config_table_get(const grpc_slice_hash_table* table, - grpc_slice path); +// The main purpose of the code here is to parse the service config in +// JSON form, which will look like this: +// +// { +// "loadBalancingPolicy": "string", // optional +// "methodConfig": [ // array of one or more method_config objects +// { +// "name": [ // array of one or more name objects +// { +// "service": "string", // required +// "method": "string", // optional +// } +// ], +// // remaining fields are optional. +// // see +// https://developers.google.com/protocol-buffers/docs/proto3#json +// // for format details. +// "waitForReady": bool, +// "timeout": "duration_string", +// "maxRequestMessageBytes": "int64_string", +// "maxResponseMessageBytes": "int64_string", +// } +// ] +// } + +namespace grpc_core { + +class ServiceConfig { + public: + /// Creates a new service config from parsing \a json_string. + /// Returns null on parse error. + static UniquePtr<ServiceConfig> Create(const char* json); + + ~ServiceConfig(); + + /// Invokes \a process_json() for each global parameter in the service + /// config. \a arg is passed as the second argument to \a process_json(). + template <typename T> + using ProcessJson = void (*)(const grpc_json*, T*); + template <typename T> + void ParseGlobalParams(ProcessJson<T> process_json, T* arg) const; + + /// Gets the LB policy name from \a service_config. + /// Returns NULL if no LB policy name was specified. + /// Caller does NOT take ownership. + const char* GetLoadBalancingPolicyName() const; + + /// Creates a method config table based on the data in \a json. + /// The table's keys are request paths. The table's value type is + /// returned by \a create_value(), based on data parsed from the JSON tree. + /// Returns null on error. + template <typename T> + using CreateValue = RefCountedPtr<T> (*)(const grpc_json* method_config_json); + template <typename T> + RefCountedPtr<SliceHashTable<RefCountedPtr<T>>> CreateMethodConfigTable( + CreateValue<T> create_value); + + /// A helper function for looking up values in the table returned by + /// \a CreateMethodConfigTable(). + /// Gets the method config for the specified \a path, which should be of + /// the form "/service/method". + /// Returns null if the method has no config. + /// Caller does NOT own a reference to the result. + template <typename T> + static RefCountedPtr<T> MethodConfigTableLookup( + const SliceHashTable<RefCountedPtr<T>>& table, grpc_slice path); + + private: + // So New() can call our private ctor. + template <typename T, typename... Args> + friend T* New(Args&&... args); + + // Takes ownership of \a json_tree. + ServiceConfig(UniquePtr<char> json_string, grpc_json* json_tree); + + // Returns the number of names specified in the method config \a json. + static size_t CountNamesInMethodConfig(grpc_json* json); + + // Returns a path string for the JSON name object specified by \a json. + // Returns null on error. + static UniquePtr<char> ParseJsonMethodName(grpc_json* json); + + // Parses the method config from \a json. Adds an entry to \a entries for + // each name found, incrementing \a idx for each entry added. + // Returns false on error. + template <typename T> + static bool ParseJsonMethodConfig( + grpc_json* json, CreateValue<T> create_value, + typename SliceHashTable<RefCountedPtr<T>>::Entry* entries, size_t* idx); + + UniquePtr<char> json_string_; // Underlying storage for json_tree. + grpc_json* json_tree_; +}; + +// +// implementation -- no user-serviceable parts below +// + +template <typename T> +void ServiceConfig::ParseGlobalParams(ProcessJson<T> process_json, + T* arg) const { + if (json_tree_->type != GRPC_JSON_OBJECT || json_tree_->key != nullptr) { + return; + } + for (grpc_json* field = json_tree_->child; field != nullptr; + field = field->next) { + if (field->key == nullptr) return; + if (strcmp(field->key, "methodConfig") == 0) continue; + process_json(field, arg); + } +} + +template <typename T> +bool ServiceConfig::ParseJsonMethodConfig( + grpc_json* json, CreateValue<T> create_value, + typename SliceHashTable<RefCountedPtr<T>>::Entry* entries, size_t* idx) { + // Construct value. + RefCountedPtr<T> method_config = create_value(json); + if (method_config == nullptr) return false; + // Construct list of paths. + InlinedVector<UniquePtr<char>, 10> paths; + for (grpc_json* child = json->child; child != nullptr; child = child->next) { + if (child->key == nullptr) continue; + if (strcmp(child->key, "name") == 0) { + if (child->type != GRPC_JSON_ARRAY) return false; + for (grpc_json* name = child->child; name != nullptr; name = name->next) { + UniquePtr<char> path = ParseJsonMethodName(name); + if (path == nullptr) return false; + paths.push_back(std::move(path)); + } + } + } + if (paths.size() == 0) return false; // No names specified. + // Add entry for each path. + for (size_t i = 0; i < paths.size(); ++i) { + entries[*idx].key = grpc_slice_from_copied_string(paths[i].get()); + entries[*idx].value = method_config; // Takes a new ref. + ++*idx; + } + // Success. + return true; +} + +template <typename T> +RefCountedPtr<SliceHashTable<RefCountedPtr<T>>> +ServiceConfig::CreateMethodConfigTable(CreateValue<T> create_value) { + // Traverse parsed JSON tree. + if (json_tree_->type != GRPC_JSON_OBJECT || json_tree_->key != nullptr) { + return nullptr; + } + size_t num_entries = 0; + typename SliceHashTable<RefCountedPtr<T>>::Entry* entries = nullptr; + for (grpc_json* field = json_tree_->child; field != nullptr; + field = field->next) { + if (field->key == nullptr) return nullptr; + if (strcmp(field->key, "methodConfig") == 0) { + if (entries != nullptr) return nullptr; // Duplicate. + if (field->type != GRPC_JSON_ARRAY) return nullptr; + // Find number of entries. + for (grpc_json* method = field->child; method != nullptr; + method = method->next) { + size_t count = CountNamesInMethodConfig(method); + if (count <= 0) return nullptr; + num_entries += count; + } + // Populate method config table entries. + entries = static_cast<typename SliceHashTable<RefCountedPtr<T>>::Entry*>( + gpr_zalloc(num_entries * + sizeof(typename SliceHashTable<RefCountedPtr<T>>::Entry))); + size_t idx = 0; + for (grpc_json* method = field->child; method != nullptr; + method = method->next) { + if (!ParseJsonMethodConfig(method, create_value, entries, &idx)) { + for (size_t i = 0; i < idx; ++i) { + grpc_slice_unref_internal(entries[i].key); + entries[i].value.reset(); + } + gpr_free(entries); + return nullptr; + } + } + GPR_ASSERT(idx == num_entries); + } + } + // Instantiate method config table. + RefCountedPtr<SliceHashTable<RefCountedPtr<T>>> method_config_table; + if (entries != nullptr) { + method_config_table = + SliceHashTable<RefCountedPtr<T>>::Create(num_entries, entries, nullptr); + gpr_free(entries); + } + return method_config_table; +} + +template <typename T> +RefCountedPtr<T> ServiceConfig::MethodConfigTableLookup( + const SliceHashTable<RefCountedPtr<T>>& table, grpc_slice path) { + const RefCountedPtr<T>* value = table.Get(path); + // If we didn't find a match for the path, try looking for a wildcard + // entry (i.e., change "/service/method" to "/service/*"). + if (value == nullptr) { + char* path_str = grpc_slice_to_c_string(path); + const char* sep = strrchr(path_str, '/') + 1; + const size_t len = (size_t)(sep - path_str); + char* buf = (char*)gpr_malloc(len + 2); // '*' and NUL + memcpy(buf, path_str, len); + buf[len] = '*'; + buf[len + 1] = '\0'; + grpc_slice wildcard_path = grpc_slice_from_copied_string(buf); + gpr_free(buf); + value = table.Get(wildcard_path); + grpc_slice_unref_internal(wildcard_path); + gpr_free(path_str); + } + return RefCountedPtr<T>(*value); +} + +} // namespace grpc_core #endif /* GRPC_CORE_LIB_TRANSPORT_SERVICE_CONFIG_H */ |