The C based gRPC (C++, Python, Ruby, Objective-C, PHP, C#) https://grpc.io/
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/*
*
* 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_H
#define GRPCPP_SERVER_H
#include <grpc/impl/codegen/port_platform.h>
#include <list>
#include <memory>
#include <vector>
#include <grpc/compression.h>
#include <grpc/support/atm.h>
#include <grpcpp/channel.h>
#include <grpcpp/completion_queue.h>
#include <grpcpp/health_check_service_interface.h>
#include <grpcpp/impl/call.h>
#include <grpcpp/impl/codegen/server_interface.h>
#include <grpcpp/impl/grpc_library.h>
#include <grpcpp/impl/rpc_service_method.h>
#include <grpcpp/security/server_credentials.h>
#include <grpcpp/support/channel_arguments.h>
#include <grpcpp/support/client_interceptor.h>
#include <grpcpp/support/config.h>
#include <grpcpp/support/status.h>
struct grpc_server;
namespace grpc {
class AsyncGenericService;
class ServerContext;
class ServerInitializer;
namespace internal {
class ExternalConnectionAcceptorImpl;
} // namespace internal
/// Represents a gRPC server.
///
/// Use a \a grpc::ServerBuilder to create, configure, and start
/// \a Server instances.
class Server : public ServerInterface, private internal::GrpcLibrary {
public:
~Server() ABSL_LOCKS_EXCLUDED(mu_) override;
/// Block until the server shuts down.
///
/// \warning The server must be either shutting down or some other thread must
/// call \a Shutdown for this function to ever return.
void Wait() ABSL_LOCKS_EXCLUDED(mu_) override;
/// Global callbacks are a set of hooks that are called when server
/// events occur. \a SetGlobalCallbacks method is used to register
/// the hooks with gRPC. Note that
/// the \a GlobalCallbacks instance will be shared among all
/// \a Server instances in an application and can be set exactly
/// once per application.
class GlobalCallbacks {
public:
virtual ~GlobalCallbacks() {}
/// Called before server is created.
virtual void UpdateArguments(ChannelArguments* /*args*/) {}
/// Called before application callback for each synchronous server request
virtual void PreSynchronousRequest(ServerContext* context) = 0;
/// Called after application callback for each synchronous server request
virtual void PostSynchronousRequest(ServerContext* context) = 0;
/// Called before server is started.
virtual void PreServerStart(Server* /*server*/) {}
/// Called after a server port is added.
virtual void AddPort(Server* /*server*/, const std::string& /*addr*/,
ServerCredentials* /*creds*/, int /*port*/) {}
};
/// Set the global callback object. Can only be called once per application.
/// Does not take ownership of callbacks, and expects the pointed to object
/// to be alive until all server objects in the process have been destroyed.
/// The same \a GlobalCallbacks object will be used throughout the
/// application and is shared among all \a Server objects.
static void SetGlobalCallbacks(GlobalCallbacks* callbacks);
/// Returns a \em raw pointer to the underlying \a grpc_server instance.
/// EXPERIMENTAL: for internal/test use only
grpc_server* c_server();
/// Returns the health check service.
HealthCheckServiceInterface* GetHealthCheckService() const {
return health_check_service_.get();
}
/// Establish a channel for in-process communication
std::shared_ptr<Channel> InProcessChannel(const ChannelArguments& args);
/// NOTE: class experimental_type is not part of the public API of this class.
/// TODO(yashykt): Integrate into public API when this is no longer
/// experimental.
class experimental_type {
public:
explicit experimental_type(Server* server) : server_(server) {}
/// Establish a channel for in-process communication with client
/// interceptors
std::shared_ptr<Channel> InProcessChannelWithInterceptors(
const ChannelArguments& args,
std::vector<
std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>
interceptor_creators);
private:
Server* server_;
};
/// NOTE: The function experimental() is not stable public API. It is a view
/// to the experimental components of this class. It may be changed or removed
/// at any time.
experimental_type experimental() { return experimental_type(this); }
protected:
/// Register a service. This call does not take ownership of the service.
/// The service must exist for the lifetime of the Server instance.
bool RegisterService(const std::string* addr, Service* service) override;
/// Try binding the server to the given \a addr endpoint
/// (port, and optionally including IP address to bind to).
///
/// It can be invoked multiple times. Should be used before
/// starting the server.
///
/// \param addr The address to try to bind to the server (eg, localhost:1234,
/// 192.168.1.1:31416, [::1]:27182, etc.).
/// \param creds The credentials associated with the server.
///
/// \return bound port number on success, 0 on failure.
///
/// \warning It is an error to call this method on an already started server.
int AddListeningPort(const std::string& addr,
ServerCredentials* creds) override;
/// NOTE: This is *NOT* a public API. The server constructors are supposed to
/// be used by \a ServerBuilder class only. The constructor will be made
/// 'private' very soon.
///
/// Server constructors. To be used by \a ServerBuilder only.
///
/// \param args The channel args
///
/// \param sync_server_cqs The completion queues to use if the server is a
/// synchronous server (or a hybrid server). The server polls for new RPCs on
/// these queues
///
/// \param min_pollers The minimum number of polling threads per server
/// completion queue (in param sync_server_cqs) to use for listening to
/// incoming requests (used only in case of sync server)
///
/// \param max_pollers The maximum number of polling threads per server
/// completion queue (in param sync_server_cqs) to use for listening to
/// incoming requests (used only in case of sync server)
///
/// \param sync_cq_timeout_msec The timeout to use when calling AsyncNext() on
/// server completion queues passed via sync_server_cqs param.
Server(ChannelArguments* args,
std::shared_ptr<std::vector<std::unique_ptr<ServerCompletionQueue>>>
sync_server_cqs,
int min_pollers, int max_pollers, int sync_cq_timeout_msec,
std::vector<std::shared_ptr<internal::ExternalConnectionAcceptorImpl>>
acceptors,
grpc_server_config_fetcher* server_config_fetcher = nullptr,
grpc_resource_quota* server_rq = nullptr,
std::vector<
std::unique_ptr<experimental::ServerInterceptorFactoryInterface>>
interceptor_creators = std::vector<std::unique_ptr<
experimental::ServerInterceptorFactoryInterface>>());
/// Start the server.
///
/// \param cqs Completion queues for handling asynchronous services. The
/// caller is required to keep all completion queues live until the server is
/// destroyed.
/// \param num_cqs How many completion queues does \a cqs hold.
void Start(ServerCompletionQueue** cqs, size_t num_cqs) override;
grpc_server* server() override { return server_; }
protected:
/// NOTE: This method is not part of the public API for this class.
void set_health_check_service(
std::unique_ptr<HealthCheckServiceInterface> service) {
health_check_service_ = std::move(service);
}
ContextAllocator* context_allocator() { return context_allocator_.get(); }
/// NOTE: This method is not part of the public API for this class.
bool health_check_service_disabled() const {
return health_check_service_disabled_;
}
private:
std::vector<std::unique_ptr<experimental::ServerInterceptorFactoryInterface>>*
interceptor_creators() override {
return &interceptor_creators_;
}
friend class AsyncGenericService;
friend class ServerBuilder;
friend class ServerInitializer;
class SyncRequest;
class CallbackRequestBase;
template <class ServerContextType>
class CallbackRequest;
class UnimplementedAsyncRequest;
class UnimplementedAsyncResponse;
/// SyncRequestThreadManager is an implementation of ThreadManager. This class
/// is responsible for polling for incoming RPCs and calling the RPC handlers.
/// This is only used in case of a Sync server (i.e a server exposing a sync
/// interface)
class SyncRequestThreadManager;
/// Register a generic service. This call does not take ownership of the
/// service. The service must exist for the lifetime of the Server instance.
void RegisterAsyncGenericService(AsyncGenericService* service) override;
/// Register a callback-based generic service. This call does not take
/// ownership of theservice. The service must exist for the lifetime of the
/// Server instance.
void RegisterCallbackGenericService(CallbackGenericService* service) override;
void RegisterContextAllocator(
std::unique_ptr<ContextAllocator> context_allocator) {
context_allocator_ = std::move(context_allocator);
}
void PerformOpsOnCall(internal::CallOpSetInterface* ops,
internal::Call* call) override;
void ShutdownInternal(gpr_timespec deadline)
ABSL_LOCKS_EXCLUDED(mu_) override;
int max_receive_message_size() const override {
return max_receive_message_size_;
}
CompletionQueue* CallbackCQ() ABSL_LOCKS_EXCLUDED(mu_) override;
ServerInitializer* initializer();
// Functions to manage the server shutdown ref count. Things that increase
// the ref count are the running state of the server (take a ref at start and
// drop it at shutdown) and each running callback RPC.
void Ref();
void UnrefWithPossibleNotify() ABSL_LOCKS_EXCLUDED(mu_);
void UnrefAndWaitLocked() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mu_);
std::vector<std::shared_ptr<internal::ExternalConnectionAcceptorImpl>>
acceptors_;
// A vector of interceptor factory objects.
// This should be destroyed after health_check_service_ and this requirement
// is satisfied by declaring interceptor_creators_ before
// health_check_service_. (C++ mandates that member objects be destroyed in
// the reverse order of initialization.)
std::vector<std::unique_ptr<experimental::ServerInterceptorFactoryInterface>>
interceptor_creators_;
int max_receive_message_size_;
/// The following completion queues are ONLY used in case of Sync API
/// i.e. if the server has any services with sync methods. The server uses
/// these completion queues to poll for new RPCs
std::shared_ptr<std::vector<std::unique_ptr<ServerCompletionQueue>>>
sync_server_cqs_;
/// List of \a ThreadManager instances (one for each cq in
/// the \a sync_server_cqs)
std::vector<std::unique_ptr<SyncRequestThreadManager>> sync_req_mgrs_;
// Server status
internal::Mutex mu_;
bool started_;
bool shutdown_ ABSL_GUARDED_BY(mu_);
bool shutdown_notified_
ABSL_GUARDED_BY(mu_); // Was notify called on the shutdown_cv_
internal::CondVar shutdown_done_cv_;
bool shutdown_done_ ABSL_GUARDED_BY(mu_) = false;
std::atomic_int shutdown_refs_outstanding_{1};
internal::CondVar shutdown_cv_;
std::shared_ptr<GlobalCallbacks> global_callbacks_;
std::vector<std::string> services_;
bool has_async_generic_service_ = false;
bool has_callback_generic_service_ = false;
bool has_callback_methods_ = false;
// Pointer to the wrapped grpc_server.
grpc_server* server_;
std::unique_ptr<ServerInitializer> server_initializer_;
std::unique_ptr<ContextAllocator> context_allocator_;
std::unique_ptr<HealthCheckServiceInterface> health_check_service_;
bool health_check_service_disabled_;
// When appropriate, use a default callback generic service to handle
// unimplemented methods
std::unique_ptr<CallbackGenericService> unimplemented_service_;
// A special handler for resource exhausted in sync case
std::unique_ptr<internal::MethodHandler> resource_exhausted_handler_;
// Handler for callback generic service, if any
std::unique_ptr<internal::MethodHandler> generic_handler_;
// callback_cq_ references the callbackable completion queue associated
// with this server (if any). It is set on the first call to CallbackCQ().
// It is _not owned_ by the server; ownership belongs with its internal
// shutdown callback tag (invoked when the CQ is fully shutdown).
std::atomic<CompletionQueue*> callback_cq_{nullptr};
// List of CQs passed in by user that must be Shutdown only after Server is
// Shutdown. Even though this is only used with NDEBUG, instantiate it in all
// cases since otherwise the size will be inconsistent.
std::vector<CompletionQueue*> cq_list_;
};
} // namespace grpc
#endif // GRPCPP_SERVER_H