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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_CONTEXT_H
#define GRPCPP_SERVER_CONTEXT_H
#include <grpc/support/port_platform.h>
#include <atomic>
#include <cassert>
#include <map>
#include <memory>
#include <type_traits>
#include <vector>
#include <grpc/grpc.h>
#include <grpc/impl/call.h>
#include <grpc/impl/compression_types.h>
#include <grpcpp/impl/call.h>
#include <grpcpp/impl/call_op_set.h>
#include <grpcpp/impl/codegen/create_auth_context.h>
#include <grpcpp/impl/codegen/metadata_map.h>
#include <grpcpp/impl/completion_queue_tag.h>
#include <grpcpp/impl/metadata_map.h>
#include <grpcpp/impl/rpc_service_method.h>
#include <grpcpp/security/auth_context.h>
#include <grpcpp/support/callback_common.h>
#include <grpcpp/support/config.h>
#include <grpcpp/support/message_allocator.h>
#include <grpcpp/support/server_callback.h>
#include <grpcpp/support/server_interceptor.h>
#include <grpcpp/support/status.h>
#include <grpcpp/support/string_ref.h>
#include <grpcpp/support/time.h>
struct grpc_metadata;
struct grpc_call;
struct census_context;
namespace grpc {
template <class W, class R>
class ServerAsyncReader;
template <class W>
class ServerAsyncWriter;
template <class W>
class ServerAsyncResponseWriter;
template <class W, class R>
class ServerAsyncReaderWriter;
template <class R>
class ServerReader;
template <class W>
class ServerWriter;
namespace internal {
template <class ServiceType, class RequestType, class ResponseType>
class BidiStreamingHandler;
template <class RequestType, class ResponseType>
class CallbackUnaryHandler;
template <class RequestType, class ResponseType>
class CallbackClientStreamingHandler;
template <class RequestType, class ResponseType>
class CallbackServerStreamingHandler;
template <class RequestType, class ResponseType>
class CallbackBidiHandler;
template <class ServiceType, class RequestType, class ResponseType>
class ClientStreamingHandler;
template <class ResponseType>
void UnaryRunHandlerHelper(const MethodHandler::HandlerParameter&,
ResponseType*, Status&);
template <class ServiceType, class RequestType, class ResponseType,
class BaseRequestType, class BaseResponseType>
class RpcMethodHandler;
template <class Base>
class FinishOnlyReactor;
template <class W, class R>
class ServerReaderWriterBody;
template <class ServiceType, class RequestType, class ResponseType>
class ServerStreamingHandler;
class ServerReactor;
template <class Streamer, bool WriteNeeded>
class TemplatedBidiStreamingHandler;
template <grpc::StatusCode code>
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<grpc::string_ref, grpc::string_ref>& 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<std::string>& cost_data);
/// Return the authentication context for this server call.
///
/// \see grpc::AuthContext.
std::shared_ptr<const grpc::AuthContext> 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<Reactor*>(&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<Reactor*>(&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 <class W, class R>
friend class grpc::ServerAsyncReader;
template <class W>
friend class grpc::ServerAsyncWriter;
template <class W>
friend class grpc::ServerAsyncResponseWriter;
template <class W, class R>
friend class grpc::ServerAsyncReaderWriter;
template <class R>
friend class grpc::ServerReader;
template <class W>
friend class grpc::ServerWriter;
template <class W, class R>
friend class grpc::internal::ServerReaderWriterBody;
template <class ResponseType>
friend void grpc::internal::UnaryRunHandlerHelper(
const internal::MethodHandler::HandlerParameter& param, ResponseType* rsp,
Status& status);
template <class ServiceType, class RequestType, class ResponseType,
class BaseRequestType, class BaseResponseType>
friend class grpc::internal::RpcMethodHandler;
template <class ServiceType, class RequestType, class ResponseType>
friend class grpc::internal::ClientStreamingHandler;
template <class ServiceType, class RequestType, class ResponseType>
friend class grpc::internal::ServerStreamingHandler;
template <class Streamer, bool WriteNeeded>
friend class grpc::internal::TemplatedBidiStreamingHandler;
template <class RequestType, class ResponseType>
friend class grpc::internal::CallbackUnaryHandler;
template <class RequestType, class ResponseType>
friend class grpc::internal::CallbackClientStreamingHandler;
template <class RequestType, class ResponseType>
friend class grpc::internal::CallbackServerStreamingHandler;
template <class RequestType, class ResponseType>
friend class grpc::internal::CallbackBidiHandler;
template <grpc::StatusCode code>
friend class grpc::internal::ErrorMethodHandler;
template <class Base>
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<void(bool)> 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<std::unique_ptr<
grpc::experimental::ServerInterceptorFactoryInterface>>& 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<const grpc::AuthContext> auth_context_;
mutable grpc::internal::MetadataMap client_metadata_;
std::multimap<std::string, std::string> initial_metadata_;
std::multimap<std::string, std::string> trailing_metadata_;
bool compression_level_set_ = false;
grpc_compression_level compression_level_;
grpc_compression_algorithm compression_algorithm_;
grpc::internal::CallOpSet<grpc::internal::CallOpSendInitialMetadata,
grpc::internal::CallOpSendMessage>
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<void(grpc::Status)> 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<void(grpc::Status)> func)
: reactor_(ctx->DefaultReactor()),
func_(std::move(func)),
call_(ctx->c_call()) {
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_call* call() override { return call_; }
grpc::internal::ServerReactor* reactor() override { return reactor_; }
grpc::ServerUnaryReactor* const reactor_;
std::atomic_bool status_set_{false};
grpc::Status status_;
const std::function<void(grpc::Status s)> func_;
grpc_call* call_;
};
alignas(Reactor) char default_reactor_[sizeof(Reactor)];
std::atomic_bool default_reactor_used_{false};
std::atomic_bool marked_cancelled_{false};
std::unique_ptr<TestServerCallbackUnary> 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<grpc::ServerContextBase, grpc::ServerContext>::value,
"improper base class");
static_assert(std::is_base_of<grpc::ServerContextBase,
grpc::CallbackServerContext>::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