// // // Copyright 2015 gRPC authors. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // // #ifndef GRPCPP_SERVER_CONTEXT_H #define GRPCPP_SERVER_CONTEXT_H #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct grpc_metadata; struct grpc_call; struct census_context; namespace grpc { template class ServerAsyncReader; template class ServerAsyncWriter; template class ServerAsyncResponseWriter; template class ServerAsyncReaderWriter; template class ServerReader; template class ServerWriter; namespace internal { template class BidiStreamingHandler; template class CallbackUnaryHandler; template class CallbackClientStreamingHandler; template class CallbackServerStreamingHandler; template class CallbackBidiHandler; template class ClientStreamingHandler; template void UnaryRunHandlerHelper(const MethodHandler::HandlerParameter&, ResponseType*, Status&); template class RpcMethodHandler; template class FinishOnlyReactor; template class ServerReaderWriterBody; template class ServerStreamingHandler; class ServerReactor; template class TemplatedBidiStreamingHandler; template class ErrorMethodHandler; } // namespace internal class ClientContext; class CompletionQueue; class GenericServerContext; class Server; class ServerInterface; class ContextAllocator; class GenericCallbackServerContext; namespace internal { class Call; } // namespace internal namespace testing { class InteropServerContextInspector; class ServerContextTestSpouse; class DefaultReactorTestPeer; } // namespace testing namespace experimental { class CallMetricRecorder; class ServerMetricRecorder; } // namespace experimental /// Base class of ServerContext. class ServerContextBase { public: virtual ~ServerContextBase(); /// Return the deadline for the server call. std::chrono::system_clock::time_point deadline() const { return grpc::Timespec2Timepoint(deadline_); } /// Return a \a gpr_timespec representation of the server call's deadline. gpr_timespec raw_deadline() const { return deadline_; } /// Add the (\a key, \a value) pair to the initial metadata /// associated with a server call. These are made available at the client side /// by the \a grpc::ClientContext::GetServerInitialMetadata() method. /// /// \warning This method should only be called before sending initial metadata /// to the client (which can happen explicitly, or implicitly when sending a /// a response message or status to the client). /// /// \param key The metadata key. If \a value is binary data, it must /// end in "-bin". /// \param value The metadata value. If its value is binary, the key name /// must end in "-bin". /// /// Metadata must conform to the following format: /// ///\verbatim /// Custom-Metadata -> Binary-Header / ASCII-Header /// Binary-Header -> {Header-Name "-bin" } {binary value} /// ASCII-Header -> Header-Name ASCII-Value /// Header-Name -> 1*( %x30-39 / %x61-7A / "_" / "-" / ".") ; 0-9 a-z _ - . /// ASCII-Value -> 1*( %x20-%x7E ) ; space and printable ASCII ///\endverbatim /// void AddInitialMetadata(const std::string& key, const std::string& value); /// Add the (\a key, \a value) pair to the initial metadata /// associated with a server call. These are made available at the client /// side by the \a grpc::ClientContext::GetServerTrailingMetadata() method. /// /// \warning This method should only be called before sending trailing /// metadata to the client (which happens when the call is finished and a /// status is sent to the client). /// /// \param key The metadata key. If \a value is binary data, /// it must end in "-bin". /// \param value The metadata value. If its value is binary, the key name /// must end in "-bin". /// /// Metadata must conform to the following format: /// ///\verbatim /// Custom-Metadata -> Binary-Header / ASCII-Header /// Binary-Header -> {Header-Name "-bin" } {binary value} /// ASCII-Header -> Header-Name ASCII-Value /// Header-Name -> 1*( %x30-39 / %x61-7A / "_" / "-" / ".") ; 0-9 a-z _ - . /// ASCII-Value -> 1*( %x20-%x7E ) ; space and printable ASCII ///\endverbatim /// void AddTrailingMetadata(const std::string& key, const std::string& value); /// Return whether this RPC failed before the server could provide its status /// back to the client. This could be because of explicit API cancellation /// from the client-side or server-side, because of deadline exceeded, network /// connection reset, HTTP/2 parameter configuration (e.g., max message size, /// max connection age), etc. It does NOT include failure due to a non-OK /// status return from the server application's request handler, including /// Status::CANCELLED. /// /// IsCancelled is always safe to call when using sync or callback API. /// When using async API, it is only safe to call IsCancelled after /// the AsyncNotifyWhenDone tag has been delivered. Thread-safe. bool IsCancelled() const; /// Cancel the Call from the server. This is a best-effort API and /// depending on when it is called, the RPC may still appear successful to /// the client. For example, if TryCancel() is called on a separate thread, it /// might race with the server handler which might return success to the /// client before TryCancel() was even started by the thread. /// /// It is the caller's responsibility to prevent such races and ensure that if /// TryCancel() is called, the serverhandler must return Status::CANCELLED. /// The only exception is that if the serverhandler is already returning an /// error status code, it is ok to not return Status::CANCELLED even if /// TryCancel() was called. Additionally, it is illegal to invoke TryCancel() /// before the call has actually begun, i.e., before metadata has been /// received from the client. /// /// For reasons such as the above, it is generally preferred to explicitly /// finish an RPC by returning Status::CANCELLED rather than using TryCancel. /// /// Note that TryCancel() does not change any of the tags that are pending /// on the completion queue. All pending tags will still be delivered /// (though their ok result may reflect the effect of cancellation). void TryCancel() const; /// Return a collection of initial metadata key-value pairs sent from the /// client. Note that keys may happen more than /// once (ie, a \a std::multimap is returned). /// /// It is safe to use this method after initial metadata has been received, /// Calls always begin with the client sending initial metadata, so this is /// safe to access as soon as the call has begun on the server side. /// /// \return A multimap of initial metadata key-value pairs from the server. const std::multimap& client_metadata() const { return *client_metadata_.map(); } /// Return the compression algorithm to be used by the server call. grpc_compression_level compression_level() const { return compression_level_; } /// Set \a level to be the compression level used for the server call. /// /// \param level The compression level used for the server call. void set_compression_level(grpc_compression_level level) { compression_level_set_ = true; compression_level_ = level; } /// Return a bool indicating whether the compression level for this call /// has been set (either implicitly or through a previous call to /// \a set_compression_level. bool compression_level_set() const { return compression_level_set_; } /// Return the compression algorithm the server call will request be used. /// Note that the gRPC runtime may decide to ignore this request, for example, /// due to resource constraints, or if the server is aware the client doesn't /// support the requested algorithm. grpc_compression_algorithm compression_algorithm() const { return compression_algorithm_; } /// Set \a algorithm to be the compression algorithm used for the server call. /// /// \param algorithm The compression algorithm used for the server call. void set_compression_algorithm(grpc_compression_algorithm algorithm); /// Set the serialized load reporting costs in \a cost_data for the call. void SetLoadReportingCosts(const std::vector& cost_data); /// Return the authentication context for this server call. /// /// \see grpc::AuthContext. std::shared_ptr auth_context() const { if (auth_context_ == nullptr) { auth_context_ = grpc::CreateAuthContext(call_.call); } return auth_context_; } /// Return the peer uri in a string. /// WARNING: this value is never authenticated or subject to any security /// related code. It must not be used for any authentication related /// functionality. Instead, use auth_context. std::string peer() const; /// Get the census context associated with this server call. const struct census_context* census_context() const; /// Should be used for framework-level extensions only. /// Applications never need to call this method. grpc_call* c_call() { return call_.call; } /// Get the \a CallMetricRecorder object for the current RPC. /// Use it to record metrics during your RPC to send back to the /// client in order to make load balancing decisions. This will /// return nullptr if the feature hasn't been enabled using /// \a EnableCallMetricRecording. experimental::CallMetricRecorder* ExperimentalGetCallMetricRecorder() { return call_metric_recorder_; } /// EXPERIMENTAL API /// Returns the call's authority. grpc::string_ref ExperimentalGetAuthority() const; protected: /// Async only. Has to be called before the rpc starts. /// Returns the tag in completion queue when the rpc finishes. /// IsCancelled() can then be called to check whether the rpc was cancelled. /// Note: the tag will only be returned if call starts. /// If the call never starts, this tag will not be returned. void AsyncNotifyWhenDone(void* tag) { has_notify_when_done_tag_ = true; async_notify_when_done_tag_ = tag; } /// NOTE: This is an API for advanced users who need custom allocators. /// Get and maybe mutate the allocator state associated with the current RPC. /// Currently only applicable for callback unary RPC methods. RpcAllocatorState* GetRpcAllocatorState() { return message_allocator_state_; } /// Get a library-owned default unary reactor for use in minimal reaction /// cases. This supports typical unary RPC usage of providing a response and /// status. It supports immediate Finish (finish from within the method /// handler) or delayed Finish (finish called after the method handler /// invocation). It does not support reacting to cancellation or completion, /// or early sending of initial metadata. Since this is a library-owned /// reactor, it should not be delete'd or freed in any way. This is more /// efficient than creating a user-owned reactor both because of avoiding an /// allocation and because its minimal reactions are optimized using a core /// surface flag that allows their reactions to run inline without any /// thread-hop. /// /// This method should not be called more than once or called after return /// from the method handler. grpc::ServerUnaryReactor* DefaultReactor() { // Short-circuit the case where a default reactor was already set up by // the TestPeer. if (test_unary_ != nullptr) { return reinterpret_cast(&default_reactor_); } new (&default_reactor_) Reactor; #ifndef NDEBUG bool old = false; assert(default_reactor_used_.compare_exchange_strong( old, true, std::memory_order_relaxed)); #else default_reactor_used_.store(true, std::memory_order_relaxed); #endif return reinterpret_cast(&default_reactor_); } /// Constructors for use by derived classes ServerContextBase(); ServerContextBase(gpr_timespec deadline, grpc_metadata_array* arr); void set_context_allocator(ContextAllocator* context_allocator) { context_allocator_ = context_allocator; } ContextAllocator* context_allocator() const { return context_allocator_; } private: friend class grpc::testing::InteropServerContextInspector; friend class grpc::testing::ServerContextTestSpouse; friend class grpc::testing::DefaultReactorTestPeer; friend class grpc::ServerInterface; friend class grpc::Server; template friend class grpc::ServerAsyncReader; template friend class grpc::ServerAsyncWriter; template friend class grpc::ServerAsyncResponseWriter; template friend class grpc::ServerAsyncReaderWriter; template friend class grpc::ServerReader; template friend class grpc::ServerWriter; template friend class grpc::internal::ServerReaderWriterBody; template friend void grpc::internal::UnaryRunHandlerHelper( const internal::MethodHandler::HandlerParameter& param, ResponseType* rsp, Status& status); template friend class grpc::internal::RpcMethodHandler; template friend class grpc::internal::ClientStreamingHandler; template friend class grpc::internal::ServerStreamingHandler; template friend class grpc::internal::TemplatedBidiStreamingHandler; template friend class grpc::internal::CallbackUnaryHandler; template friend class grpc::internal::CallbackClientStreamingHandler; template friend class grpc::internal::CallbackServerStreamingHandler; template friend class grpc::internal::CallbackBidiHandler; template friend class grpc::internal::ErrorMethodHandler; template friend class grpc::internal::FinishOnlyReactor; friend class grpc::ClientContext; friend class grpc::GenericServerContext; friend class grpc::GenericCallbackServerContext; /// Prevent copying. ServerContextBase(const ServerContextBase&); ServerContextBase& operator=(const ServerContextBase&); class CompletionOp; void BeginCompletionOp( grpc::internal::Call* call, std::function callback, grpc::internal::ServerCallbackCall* callback_controller); /// Return the tag queued by BeginCompletionOp() grpc::internal::CompletionQueueTag* GetCompletionOpTag(); void set_call(grpc_call* call, bool call_metric_recording_enabled, experimental::ServerMetricRecorder* server_metric_recorder) { call_.call = call; if (call_metric_recording_enabled) { CreateCallMetricRecorder(server_metric_recorder); } } void BindDeadlineAndMetadata(gpr_timespec deadline, grpc_metadata_array* arr); uint32_t initial_metadata_flags() const { return 0; } grpc::experimental::ServerRpcInfo* set_server_rpc_info( const char* method, grpc::internal::RpcMethod::RpcType type, const std::vector>& creators) { if (!creators.empty()) { rpc_info_ = new grpc::experimental::ServerRpcInfo(this, method, type); rpc_info_->RegisterInterceptors(creators); } return rpc_info_; } void set_message_allocator_state(RpcAllocatorState* allocator_state) { message_allocator_state_ = allocator_state; } void MaybeMarkCancelledOnRead() { if (grpc_call_failed_before_recv_message(call_.call)) { marked_cancelled_.store(true, std::memory_order_release); } } // This should be called only once and only when call metric recording is // enabled. void CreateCallMetricRecorder( experimental::ServerMetricRecorder* server_metric_recorder = nullptr); struct CallWrapper { ~CallWrapper(); grpc_call* call = nullptr; }; // NOTE: call_ must be the first data member of this object so that its // destructor is the last to be called, since its destructor may unref // the underlying core call which holds the arena that may be used to // hold this object. CallWrapper call_; CompletionOp* completion_op_ = nullptr; bool has_notify_when_done_tag_ = false; void* async_notify_when_done_tag_ = nullptr; grpc::internal::CallbackWithSuccessTag completion_tag_; gpr_timespec deadline_; grpc::CompletionQueue* cq_ = nullptr; bool sent_initial_metadata_ = false; mutable std::shared_ptr auth_context_; mutable grpc::internal::MetadataMap client_metadata_; std::multimap initial_metadata_; std::multimap trailing_metadata_; bool compression_level_set_ = false; grpc_compression_level compression_level_; grpc_compression_algorithm compression_algorithm_; grpc::internal::CallOpSet pending_ops_; bool has_pending_ops_ = false; grpc::experimental::ServerRpcInfo* rpc_info_ = nullptr; RpcAllocatorState* message_allocator_state_ = nullptr; ContextAllocator* context_allocator_ = nullptr; experimental::CallMetricRecorder* call_metric_recorder_ = nullptr; class Reactor : public grpc::ServerUnaryReactor { public: void OnCancel() override {} void OnDone() override {} // Override InternalInlineable for this class since its reactions are // trivial and thus do not need to be run from the executor (triggering a // thread hop). This should only be used by internal reactors (thus the // name) and not by user application code. bool InternalInlineable() override { return true; } }; void SetupTestDefaultReactor(std::function func) { // NOLINTNEXTLINE(modernize-make-unique) test_unary_.reset(new TestServerCallbackUnary(this, std::move(func))); } bool test_status_set() const { return (test_unary_ != nullptr) && test_unary_->status_set(); } grpc::Status test_status() const { return test_unary_->status(); } class TestServerCallbackUnary : public grpc::ServerCallbackUnary { public: TestServerCallbackUnary(ServerContextBase* ctx, std::function func) : reactor_(ctx->DefaultReactor()), func_(std::move(func)) { this->BindReactor(reactor_); } void Finish(grpc::Status s) override { status_ = s; func_(std::move(s)); status_set_.store(true, std::memory_order_release); } void SendInitialMetadata() override {} bool status_set() const { return status_set_.load(std::memory_order_acquire); } grpc::Status status() const { return status_; } private: void CallOnDone() override {} grpc::internal::ServerReactor* reactor() override { return reactor_; } grpc::ServerUnaryReactor* const reactor_; std::atomic_bool status_set_{false}; grpc::Status status_; const std::function func_; }; alignas(Reactor) char default_reactor_[sizeof(Reactor)]; std::atomic_bool default_reactor_used_{false}; std::atomic_bool marked_cancelled_{false}; std::unique_ptr test_unary_; }; /// A ServerContext or CallbackServerContext allows the code implementing a /// service handler to: /// /// - Add custom initial and trailing metadata key-value pairs that will /// propagated to the client side. /// - Control call settings such as compression and authentication. /// - Access metadata coming from the client. /// - Get performance metrics (ie, census). /// /// Context settings are only relevant to the call handler they are supplied to, /// that is to say, they aren't sticky across multiple calls. Some of these /// settings, such as the compression options, can be made persistent at server /// construction time by specifying the appropriate \a ChannelArguments /// to a \a grpc::ServerBuilder, via \a ServerBuilder::AddChannelArgument. /// /// \warning ServerContext instances should \em not be reused across rpcs. class ServerContext : public ServerContextBase { public: ServerContext() {} // for async calls using ServerContextBase::AddInitialMetadata; using ServerContextBase::AddTrailingMetadata; using ServerContextBase::auth_context; using ServerContextBase::c_call; using ServerContextBase::census_context; using ServerContextBase::client_metadata; using ServerContextBase::compression_algorithm; using ServerContextBase::compression_level; using ServerContextBase::compression_level_set; using ServerContextBase::deadline; using ServerContextBase::IsCancelled; using ServerContextBase::peer; using ServerContextBase::raw_deadline; using ServerContextBase::set_compression_algorithm; using ServerContextBase::set_compression_level; using ServerContextBase::SetLoadReportingCosts; using ServerContextBase::TryCancel; // Sync/CQ-based Async ServerContext only using ServerContextBase::AsyncNotifyWhenDone; private: // Constructor for internal use by server only friend class grpc::Server; ServerContext(gpr_timespec deadline, grpc_metadata_array* arr) : ServerContextBase(deadline, arr) {} // CallbackServerContext only using ServerContextBase::DefaultReactor; using ServerContextBase::GetRpcAllocatorState; /// Prevent copying. ServerContext(const ServerContext&) = delete; ServerContext& operator=(const ServerContext&) = delete; }; class CallbackServerContext : public ServerContextBase { public: /// Public constructors are for direct use only by mocking tests. In practice, /// these objects will be owned by the library. CallbackServerContext() {} using ServerContextBase::AddInitialMetadata; using ServerContextBase::AddTrailingMetadata; using ServerContextBase::auth_context; using ServerContextBase::c_call; using ServerContextBase::census_context; using ServerContextBase::client_metadata; using ServerContextBase::compression_algorithm; using ServerContextBase::compression_level; using ServerContextBase::compression_level_set; using ServerContextBase::context_allocator; using ServerContextBase::deadline; using ServerContextBase::IsCancelled; using ServerContextBase::peer; using ServerContextBase::raw_deadline; using ServerContextBase::set_compression_algorithm; using ServerContextBase::set_compression_level; using ServerContextBase::set_context_allocator; using ServerContextBase::SetLoadReportingCosts; using ServerContextBase::TryCancel; // CallbackServerContext only using ServerContextBase::DefaultReactor; using ServerContextBase::GetRpcAllocatorState; private: // Sync/CQ-based Async ServerContext only using ServerContextBase::AsyncNotifyWhenDone; /// Prevent copying. CallbackServerContext(const CallbackServerContext&) = delete; CallbackServerContext& operator=(const CallbackServerContext&) = delete; }; /// A CallbackServerContext allows users to use the contents of the /// CallbackServerContext or GenericCallbackServerContext structure for the /// callback API. /// The library will invoke the allocator any time a new call is initiated. /// and call the Release method after the server OnDone. class ContextAllocator { public: virtual ~ContextAllocator() {} virtual CallbackServerContext* NewCallbackServerContext() { return nullptr; } virtual GenericCallbackServerContext* NewGenericCallbackServerContext() { return nullptr; } virtual void Release(CallbackServerContext*) {} virtual void Release(GenericCallbackServerContext*) {} }; } // namespace grpc static_assert( std::is_base_of::value, "improper base class"); static_assert(std::is_base_of::value, "improper base class"); static_assert(sizeof(grpc::ServerContextBase) == sizeof(grpc::ServerContext), "wrong size"); static_assert(sizeof(grpc::ServerContextBase) == sizeof(grpc::CallbackServerContext), "wrong size"); #endif // GRPCPP_SERVER_CONTEXT_H