I/O object for server-side, client-streaming rpcs. More...

#include <agrpc/server_rpc.hpp>

Inheritance diagram for agrpc::ServerRPC< RequestClientStreaming, TraitsT, Executor >:

Collaboration diagram for agrpc::ServerRPC< RequestClientStreaming, TraitsT, Executor >:

Classes
struct	rebind_executor
	Rebind the ServerRPC to another executor. More...

Public Types
using	Request = RequestT
	The response message type.

using	Response = ResponseT
	The request message type.

using	Traits = TraitsT
	The traits type.

using	Ptr = agrpc::ServerRPCPtr< ServerRPC >
	ServerRPCPtr specialized on this type.

using	executor_type = Executor
	The executor type.

Public Member Functions
	ServerRPC ()=delete
	Deleted default constructor.

template<class CompletionToken = detail::DefaultCompletionTokenT<Executor>>
auto	read (RequestT &req, CompletionToken &&token=detail::DefaultCompletionTokenT< Executor >{})
	Receive a message from the client. More...

template<class CompletionToken = detail::DefaultCompletionTokenT<Executor>>
auto	finish (const ResponseT &response, const grpc::Status &status, CompletionToken &&token=detail::DefaultCompletionTokenT< Executor >{})
	Finish the rpc. More...

template<class CompletionToken = detail::DefaultCompletionTokenT<Executor>>
auto	finish_with_error (const grpc::Status &status, CompletionToken &&token=detail::DefaultCompletionTokenT< Executor >{})
	Finish the rpc with an error. More...

auto	send_initial_metadata (CompletionToken &&token=detail::DefaultCompletionTokenT< Executor >{})
	Send initial metadata. More...

bool	is_done () const noexcept
	Is this rpc done? More...

auto	wait_for_done (CompletionToken &&token=detail::DefaultCompletionTokenT< Executor >{})
	Wait for done. More...

const executor_type &	get_executor () const noexcept
	Get the executor. More...

const executor_type &	get_scheduler () const noexcept
	Get the scheduler. More...

auto &	context ()
	Get the underlying `ServerContext`

const auto &	context () const
	Get the underlying `ServerContext` (const overload)

void	cancel () noexcept
	Cancel this RPC. More...

Static Public Member Functions
static constexpr std::string_view	service_name () noexcept
	Name of the gRPC service. More...

static constexpr std::string_view	method_name () noexcept
	Name of the gRPC method. More...

Static Public Attributes
static constexpr agrpc::ServerRPCType	TYPE = agrpc::ServerRPCType::CLIENT_STREAMING
	The rpc type.

Detailed Description

template<class ServiceT, class RequestT, class ResponseT, detail::ServerClientStreamingRequest< ServiceT, RequestT, ResponseT > RequestClientStreaming, class TraitsT, class Executor>
class agrpc::ServerRPC< RequestClientStreaming, TraitsT, Executor >

I/O object for server-side, client-streaming rpcs.

Use one of the agrpc::register_ functions to set up request handling.

Example:

void server_rpc_client_streaming(agrpc::GrpcContext& grpc_context,
                                 example::v1::Example::AsyncService& service)
{
    using RPC = asio::use_awaitable_t<>::as_default_on_t<
        agrpc::ServerRPC<&example::v1::Example::AsyncService::RequestClientStreaming>>;
    agrpc::register_awaitable_rpc_handler<RPC>(
        grpc_context, service,
        [](RPC& rpc) -> asio::awaitable<void>
        {
            RPC::Request request;
            while (co_await rpc.read(request))
            {
                std::cout << "Request: " << request.integer() << std::endl;
            }
            RPC::Response response;
            response.set_integer(42);
            co_await rpc.finish(response, grpc::Status::OK);
 
            // Alternatively finish with an error:
            co_await rpc.finish_with_error(grpc::Status::CANCELLED);
        },
        asio::detached);
}

Based on .proto file:

syntax = "proto3";
 
package example.v1;
 
service Example {
  rpc ServerStreaming(Request) returns (stream Response) {}
 
  rpc ClientStreaming(stream Request) returns (Response) {}
 
  rpc BidirectionalStreaming(stream Request) returns (stream Response) {}
 
  rpc Unary(Request) returns (Response) {}
}
 
message Request {
  int32 integer = 1;
}
 
message Response {
  int32 integer = 1;
}

Template Parameters

RequestUnary	A pointer to the generated gRPC method.
Traits	A type used to customize this rpc. See `agrpc::DefaultServerRPCTraits`.
Executor	The executor type, must be capable of referring to a `agrpc::GrpcContext`.

Per-Operation Cancellation

(except wait_for_done) Terminal and partial. Cancellation is performed by invoking grpc::ServerContext::TryCancel. After successful cancellation no further operations should be started on the rpc. Operations are also cancelled when the deadline of the rpc has been reached.

Since: 2.7.0

Member Function Documentation

◆ service_name()

template<class ServiceT , class RequestT , class ResponseT , detail::ServerClientStreamingRequest< ServiceT, RequestT, ResponseT > RequestClientStreaming, class TraitsT , class Executor >

static constexpr std::string_view agrpc::ServerRPC< RequestClientStreaming, TraitsT, Executor >::service_name ( )

inlinestaticconstexprnoexcept

Name of the gRPC service.

Equal to the generated Service::service_full_name().

E.g. for the .proto schema

package example.v1;
 
service Example { ... }

the return value would be "example.v1.Example".

◆ method_name()

template<class ServiceT , class RequestT , class ResponseT , detail::ServerClientStreamingRequest< ServiceT, RequestT, ResponseT > RequestClientStreaming, class TraitsT , class Executor >

static constexpr std::string_view agrpc::ServerRPC< RequestClientStreaming, TraitsT, Executor >::method_name ( )

inlinestaticconstexprnoexcept

Name of the gRPC method.

E.g. for agrpc::ServerRPC<&example::Example::AsyncService::RequestMyMethod> the return value would be "MyMethod".

◆ read()

template<class ServiceT , class RequestT , class ResponseT , detail::ServerClientStreamingRequest< ServiceT, RequestT, ResponseT > RequestClientStreaming, class TraitsT , class Executor >

template<class CompletionToken = detail::DefaultCompletionTokenT<Executor>>

auto agrpc::ServerRPC< RequestClientStreaming, TraitsT, Executor >::read	(	RequestT &	req,
		CompletionToken &&	token = `detail::DefaultCompletionTokenT<Executor>{}`
	)

inline

Receive a message from the client.

May not be called currently with finish/finish_with_error. It is not meaningful to call it concurrently with another read on the same rpc since reads on the same stream are delivered in order.

Parameters

token A completion token like asio::yield_context or agrpc::use_sender. The completion signature is void(bool). true indicates that a valid message was read. false when there will be no more incoming messages, either because the other side has called WritesDone() or the stream has failed (or been cancelled).

◆ finish()

template<class ServiceT , class RequestT , class ResponseT , detail::ServerClientStreamingRequest< ServiceT, RequestT, ResponseT > RequestClientStreaming, class TraitsT , class Executor >

template<class CompletionToken = detail::DefaultCompletionTokenT<Executor>>

auto agrpc::ServerRPC< RequestClientStreaming, TraitsT, Executor >::finish	(	const ResponseT &	response,
		const grpc::Status &	status,
		CompletionToken &&	token = `detail::DefaultCompletionTokenT<Executor>{}`
	)

inline

Finish the rpc.

Indicate that the stream is to be finished with a certain status code and also send out a response to the client.

Should not be used concurrently with other operations and may only be called once.

It is appropriate to call this method when:

all messages from the client have been received (either known implicitly, or explicitly because a previous read operation completed with false).

This operation will end when the server has finished sending out initial and trailing metadata, response message, and status, or if some failure occurred when trying to do so.

Note: Response is not sent if status has a non-OK code.

GRPC does not take ownership or a reference to response or status, so it is safe to deallocate once finish returns, unless a deferred completion token like agrpc::use_sender or asio::deferred is used.

Parameters

token A completion token like asio::yield_context or agrpc::use_sender. The completion signature is void(bool). true means that the data/metadata/status/etc is going to go to the wire. If it is false, it is not going to the wire because the call is already dead (i.e., canceled, deadline expired, other side dropped the channel, etc).

◆ finish_with_error()

template<class ServiceT , class RequestT , class ResponseT , detail::ServerClientStreamingRequest< ServiceT, RequestT, ResponseT > RequestClientStreaming, class TraitsT , class Executor >

template<class CompletionToken = detail::DefaultCompletionTokenT<Executor>>

auto agrpc::ServerRPC< RequestClientStreaming, TraitsT, Executor >::finish_with_error	(	const grpc::Status &	status,
		CompletionToken &&	token = `detail::DefaultCompletionTokenT<Executor>{}`
	)

inline

Finish the rpc with an error.

Indicate that the stream is to be finished with a certain non-OK status code.

Should not be used concurrently with other operations and may only be called once.

This call is meant to end the call with some error, and can be called at any point that the server would like to "fail" the call (except during send_initial_metadata).

This operation will end when the server has finished sending out initial and trailing metadata and status, or if some failure occurred when trying to do so.

GRPC does not take ownership or a reference to status, so it is safe to to deallocate once finish_with_error returns, unless a deferred completion token like agrpc::use_sender or asio::deferred is used.

Parameters

token A completion token like asio::yield_context or agrpc::use_sender. The completion signature is void(bool). true means that the data/metadata/status/etc is going to go to the wire. If it is false, it is not going to the wire because the call is already dead (i.e., canceled, deadline expired, other side dropped the channel, etc).

◆ send_initial_metadata()

auto agrpc::detail::ServerRPCBase< grpc::ServerAsyncReader< ResponseT, RequestT > , TraitsT , Executor >::send_initial_metadata ( CompletionToken && token = detail::DefaultCompletionTokenT<Executor>{} )

inlineinherited

Send initial metadata.

Request notification of the sending of initial metadata to the client.

This call is optional, but if it is used, it cannot be used concurrently with or after the finish/finish_with_error method.

Parameters

token A completion token like asio::yield_context or agrpc::use_sender. The completion signature is void(bool). true means that the data/metadata/status/etc is going to go to the wire. If it is false, it is not going to the wire because the call is already dead (i.e., canceled, deadline expired, other side dropped the channel, etc).

◆ is_done()

bool agrpc::detail::ServerRPCNotifyWhenDoneMixin< IsNotifyWhenDone, grpc::ServerAsyncReader< ResponseT, RequestT > , Executor >::is_done ( ) const

inlinenoexceptinherited

Is this rpc done?

Only available if Traits contain NOTIFY_WHEN_DONE = true.

Returns true if NotifyWhenDone has fired which indicates the finish has been called or that the rpc is dead (i.e., canceled, deadline expired, other side dropped the channel, etc).

Thread-safe

◆ wait_for_done()

auto agrpc::detail::ServerRPCNotifyWhenDoneMixin< IsNotifyWhenDone, grpc::ServerAsyncReader< ResponseT, RequestT > , Executor >::wait_for_done ( CompletionToken && token = detail::DefaultCompletionTokenT<Executor>{} )

inlineinherited

Wait for done.

Only available if Traits contain NOTIFY_WHEN_DONE = true.

Request notification of the completion of this rpc, either due to calling finish or because the rpc is dead (i.e., canceled, deadline expired, other side dropped the channel, etc). rpc.context().IsCancelled() may only be called after this operation completes.

Cancelling this operation does not invoke grpc::ServerContext::TryCancel.

Parameters

token A completion token like asio::yield_context or agrpc::use_sender. The completion signature is void().

◆ get_executor()

template<class Executor >

const executor_type & agrpc::detail::RPCExecutorBase< Executor >::get_executor ( ) const

inlinenoexceptinherited

Get the executor.

Thread-safe

◆ get_scheduler()

template<class Executor >

const executor_type & agrpc::detail::RPCExecutorBase< Executor >::get_scheduler ( ) const

inlinenoexceptinherited

Get the scheduler.

Thread-safe

Since: 2.9.0

◆ cancel()

template<class Responder >

void agrpc::detail::ServerRPCContextBase< Responder >::cancel ( )

inlinenoexceptinherited

Cancel this RPC.

Effectively calls context().TryCancel().

Thread-safe

Classes

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Detailed Description

Member Function Documentation

◆ service_name()

◆ method_name()

◆ read()

◆ finish()

◆ finish_with_error()

◆ send_initial_metadata()

◆ is_done()

◆ wait_for_done()

◆ get_executor()

◆ get_scheduler()

◆ cancel()