//
//
// 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_INTERFACE_H
#define GRPCPP_SERVER_INTERFACE_H
#include <grpc/support/port_platform.h>
#include <grpc/grpc.h>
#include <grpc/impl/grpc_types.h>
#include <grpc/support/log.h>
#include <grpc/support/time.h>
#include <grpcpp/impl/call.h>
#include <grpcpp/impl/call_hook.h>
#include <grpcpp/impl/codegen/interceptor_common.h>
#include <grpcpp/impl/completion_queue_tag.h>
#include <grpcpp/impl/rpc_service_method.h>
#include <grpcpp/server_context.h>
#include <grpcpp/support/byte_buffer.h>
namespace grpc {
class AsyncGenericService;
class Channel;
class CompletionQueue;
class GenericServerContext;
class ServerCompletionQueue;
class ServerCredentials;
class Service;
/// Models a gRPC server.
///
/// Servers are configured and started via \a grpc::ServerBuilder.
namespace internal {
class ServerAsyncStreamingInterface;
} // namespace internal
class CallbackGenericService;
namespace experimental {
class ServerInterceptorFactoryInterface;
class ServerMetricRecorder;
} // namespace experimental
class ServerInterface : public internal::CallHook {
public:
~ServerInterface() override {}
/// \a Shutdown does the following things:
///
/// 1. Shutdown the server: deactivate all listening ports, mark it in
/// "shutdown mode" so that further call Request's or incoming RPC matches
/// are no longer allowed. Also return all Request'ed-but-not-yet-active
/// calls as failed (!ok). This refers to calls that have been requested
/// at the server by the server-side library or application code but that
/// have not yet been matched to incoming RPCs from the client. Note that
/// this would even include default calls added automatically by the gRPC
/// C++ API without the user's input (e.g., "Unimplemented RPC method")
///
/// 2. Block until all rpc method handlers invoked automatically by the sync
/// API finish.
///
/// 3. If all pending calls complete (and all their operations are
/// retrieved by Next) before \a deadline expires, this finishes
/// gracefully. Otherwise, forcefully cancel all pending calls associated
/// with the server after \a deadline expires. In the case of the sync API,
/// if the RPC function for a streaming call has already been started and
/// takes a week to complete, the RPC function won't be forcefully
/// terminated (since that would leave state corrupt and incomplete) and
/// the method handler will just keep running (which will prevent the
/// server from completing the "join" operation that it needs to do at
/// shutdown time).
///
/// All completion queue associated with the server (for example, for async
/// serving) must be shutdown *after* this method has returned:
/// See \a ServerBuilder::AddCompletionQueue for details.
/// They must also be drained (by repeated Next) after being shutdown.
///
/// \param deadline How long to wait until pending rpcs are forcefully
/// terminated.
template <class T>
void Shutdown(const T& deadline) {
ShutdownInternal(TimePoint<T>(deadline).raw_time());
}
/// Shutdown the server without a deadline and forced cancellation.
///
/// All completion queue associated with the server (for example, for async
/// serving) must be shutdown *after* this method has returned:
/// See \a ServerBuilder::AddCompletionQueue for details.
void Shutdown() { ShutdownInternal(gpr_inf_future(GPR_CLOCK_MONOTONIC)); }
/// Block waiting for all work to complete.
///
/// \warning The server must be either shutting down or some other thread must
/// call \a Shutdown for this function to ever return.
virtual void Wait() = 0;
protected:
friend class grpc::Service;
/// Register a service. This call does not take ownership of the service.
/// The service must exist for the lifetime of the Server instance.
virtual bool RegisterService(const TString* host, Service* service) = 0;
/// Register a generic service. This call does not take ownership of the
/// service. The service must exist for the lifetime of the Server instance.
virtual void RegisterAsyncGenericService(AsyncGenericService* service) = 0;
/// Register a callback generic service. This call does not take ownership of
/// the service. The service must exist for the lifetime of the Server
/// instance. May not be abstract since this is a post-1.0 API addition.
virtual void RegisterCallbackGenericService(CallbackGenericService*
/*service*/) {}
/// Tries to bind \a server to the given \a addr.
///
/// It can be invoked multiple times.
///
/// \param addr The address to try to bind to the server (eg, localhost:1234,
/// 192.168.1.1:31416, [::1]:27182, etc.).
/// \params creds The credentials associated with the server.
///
/// \return bound port number on success, 0 on failure.
///
/// \warning It's an error to call this method on an already started server.
virtual int AddListeningPort(const TString& addr,
ServerCredentials* creds) = 0;
/// 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.
virtual void Start(grpc::ServerCompletionQueue** cqs, size_t num_cqs) = 0;
virtual void ShutdownInternal(gpr_timespec deadline) = 0;
virtual int max_receive_message_size() const = 0;
virtual grpc_server* server() = 0;
void PerformOpsOnCall(internal::CallOpSetInterface* ops,
internal::Call* call) override = 0;
class BaseAsyncRequest : public internal::CompletionQueueTag {
public:
BaseAsyncRequest(ServerInterface* server, grpc::ServerContext* context,
internal::ServerAsyncStreamingInterface* stream,
grpc::CompletionQueue* call_cq,
grpc::ServerCompletionQueue* notification_cq, void* tag,
bool delete_on_finalize);
~BaseAsyncRequest() override;
bool FinalizeResult(void** tag, bool* status) override;
private:
void ContinueFinalizeResultAfterInterception();
protected:
ServerInterface* const server_;
grpc::ServerContext* const context_;
internal::ServerAsyncStreamingInterface* const stream_;
grpc::CompletionQueue* const call_cq_;
grpc::ServerCompletionQueue* const notification_cq_;
void* const tag_;
const bool delete_on_finalize_;
grpc_call* call_;
internal::Call call_wrapper_;
internal::InterceptorBatchMethodsImpl interceptor_methods_;
bool done_intercepting_;
bool call_metric_recording_enabled_;
experimental::ServerMetricRecorder* server_metric_recorder_;
};
/// RegisteredAsyncRequest is not part of the C++ API
class RegisteredAsyncRequest : public BaseAsyncRequest {
public:
RegisteredAsyncRequest(ServerInterface* server,
grpc::ServerContext* context,
internal::ServerAsyncStreamingInterface* stream,
grpc::CompletionQueue* call_cq,
grpc::ServerCompletionQueue* notification_cq,
void* tag, const char* name,
internal::RpcMethod::RpcType type);
bool FinalizeResult(void** tag, bool* status) override {
// If we are done intercepting, then there is nothing more for us to do
if (done_intercepting_) {
return BaseAsyncRequest::FinalizeResult(tag, status);
}
call_wrapper_ = grpc::internal::Call(
call_, server_, call_cq_, server_->max_receive_message_size(),
context_->set_server_rpc_info(name_, type_,
*server_->interceptor_creators()));
return BaseAsyncRequest::FinalizeResult(tag, status);
}
protected:
void IssueRequest(void* registered_method, grpc_byte_buffer** payload,
grpc::ServerCompletionQueue* notification_cq);
const char* name_;
const internal::RpcMethod::RpcType type_;
};
class NoPayloadAsyncRequest final : public RegisteredAsyncRequest {
public:
NoPayloadAsyncRequest(internal::RpcServiceMethod* registered_method,
ServerInterface* server, grpc::ServerContext* context,
internal::ServerAsyncStreamingInterface* stream,
grpc::CompletionQueue* call_cq,
grpc::ServerCompletionQueue* notification_cq,
void* tag)
: RegisteredAsyncRequest(
server, context, stream, call_cq, notification_cq, tag,
registered_method->name(), registered_method->method_type()) {
IssueRequest(registered_method->server_tag(), nullptr, notification_cq);
}
// uses RegisteredAsyncRequest::FinalizeResult
};
template <class Message>
class PayloadAsyncRequest final : public RegisteredAsyncRequest {
public:
PayloadAsyncRequest(internal::RpcServiceMethod* registered_method,
ServerInterface* server, grpc::ServerContext* context,
internal::ServerAsyncStreamingInterface* stream,
grpc::CompletionQueue* call_cq,
grpc::ServerCompletionQueue* notification_cq, void* tag,
Message* request)
: RegisteredAsyncRequest(
server, context, stream, call_cq, notification_cq, tag,
registered_method->name(), registered_method->method_type()),
registered_method_(registered_method),
request_(request) {
IssueRequest(registered_method->server_tag(), payload_.bbuf_ptr(),
notification_cq);
}
~PayloadAsyncRequest() override {
payload_.Release(); // We do not own the payload_
}
bool FinalizeResult(void** tag, bool* status) override {
// If we are done intercepting, then there is nothing more for us to do
if (done_intercepting_) {
return RegisteredAsyncRequest::FinalizeResult(tag, status);
}
if (*status) {
if (!payload_.Valid() || !SerializationTraits<Message>::Deserialize(
payload_.bbuf_ptr(), request_)
.ok()) {
// If deserialization fails, we cancel the call and instantiate
// a new instance of ourselves to request another call. We then
// return false, which prevents the call from being returned to
// the application.
grpc_call_cancel_with_status(call_, GRPC_STATUS_INTERNAL,
"Unable to parse request", nullptr);
grpc_call_unref(call_);
new PayloadAsyncRequest(registered_method_, server_, context_,
stream_, call_cq_, notification_cq_, tag_,
request_);
delete this;
return false;
}
}
// Set interception point for recv message
interceptor_methods_.AddInterceptionHookPoint(
experimental::InterceptionHookPoints::POST_RECV_MESSAGE);
interceptor_methods_.SetRecvMessage(request_, nullptr);
return RegisteredAsyncRequest::FinalizeResult(tag, status);
}
private:
internal::RpcServiceMethod* const registered_method_;
Message* const request_;
ByteBuffer payload_;
};
class GenericAsyncRequest : public BaseAsyncRequest {
public:
GenericAsyncRequest(ServerInterface* server, GenericServerContext* context,
internal::ServerAsyncStreamingInterface* stream,
grpc::CompletionQueue* call_cq,
grpc::ServerCompletionQueue* notification_cq, void* tag,
bool delete_on_finalize, bool issue_request = true);
bool FinalizeResult(void** tag, bool* status) override;
protected:
void IssueRequest();
private:
grpc_call_details call_details_;
};
template <class Message>
void RequestAsyncCall(internal::RpcServiceMethod* method,
grpc::ServerContext* context,
internal::ServerAsyncStreamingInterface* stream,
grpc::CompletionQueue* call_cq,
grpc::ServerCompletionQueue* notification_cq, void* tag,
Message* message) {
GPR_ASSERT(method);
new PayloadAsyncRequest<Message>(method, this, context, stream, call_cq,
notification_cq, tag, message);
}
void RequestAsyncCall(internal::RpcServiceMethod* method,
grpc::ServerContext* context,
internal::ServerAsyncStreamingInterface* stream,
grpc::CompletionQueue* call_cq,
grpc::ServerCompletionQueue* notification_cq,
void* tag) {
GPR_ASSERT(method);
new NoPayloadAsyncRequest(method, this, context, stream, call_cq,
notification_cq, tag);
}
void RequestAsyncGenericCall(GenericServerContext* context,
internal::ServerAsyncStreamingInterface* stream,
grpc::CompletionQueue* call_cq,
grpc::ServerCompletionQueue* notification_cq,
void* tag) {
new GenericAsyncRequest(this, context, stream, call_cq, notification_cq,
tag, true);
}
private:
// EXPERIMENTAL
// Getter method for the vector of interceptor factory objects.
// Returns a nullptr (rather than being pure) since this is a post-1.0 method
// and adding a new pure method to an interface would be a breaking change
// (even though this is private and non-API)
virtual std::vector<
std::unique_ptr<experimental::ServerInterceptorFactoryInterface>>*
interceptor_creators() {
return nullptr;
}
// Whether per-call load reporting is enabled.
virtual bool call_metric_recording_enabled() const = 0;
// Interface to read or update server-wide metrics. Returns null when not set.
virtual experimental::ServerMetricRecorder* server_metric_recorder()
const = 0;
// A method to get the callbackable completion queue associated with this
// server. If the return value is nullptr, this server doesn't support
// callback operations.
// TODO(vjpai): Consider a better default like using a global CQ
// Returns nullptr (rather than being pure) since this is a post-1.0 method
// and adding a new pure method to an interface would be a breaking change
// (even though this is private and non-API)
virtual grpc::CompletionQueue* CallbackCQ() { return nullptr; }
};
} // namespace grpc
#endif // GRPCPP_SERVER_INTERFACE_H