lidavidm commented on a change in pull request #12465:
URL: https://github.com/apache/arrow/pull/12465#discussion_r817148095
##########
File path: cpp/src/arrow/flight/server.cc
##########
@@ -442,20 +196,69 @@ class GrpcAddCallHeaders : public AddCallHeaders {
grpc::ServerContext* context_;
};
+class GetDataStream : public internal::TransportDataStream {
+ public:
+ explicit GetDataStream(ServerWriter<pb::FlightData>* writer) :
writer_(writer) {}
+
+ Status WriteData(const FlightPayload& payload) override {
+ return internal::WritePayload(payload, writer_);
+ }
+
+ private:
+ ServerWriter<pb::FlightData>* writer_;
+};
+
+class PutDataStream final : public internal::TransportDataStream {
+ public:
+ explicit PutDataStream(grpc::ServerReaderWriter<pb::PutResult,
pb::FlightData>* stream)
+ : stream_(stream) {}
+
+ bool ReadData(internal::FlightData* data) override {
+ return internal::ReadPayload(&*stream_, data);
+ }
+ Status WritePutMetadata(const Buffer& metadata) override {
+ pb::PutResult message{};
+ message.set_app_metadata(metadata.data(), metadata.size());
+ if (stream_->Write(message)) {
+ return Status::OK();
+ }
+ return Status::IOError("Unknown error writing metadata.");
+ }
+
+ private:
+ grpc::ServerReaderWriter<pb::PutResult, pb::FlightData>* stream_;
+};
+
+class ExchangeDataStream final : public internal::TransportDataStream {
+ public:
+ explicit ExchangeDataStream(
+ grpc::ServerReaderWriter<pb::FlightData, pb::FlightData>* stream)
+ : stream_(stream) {}
+
+ bool ReadData(internal::FlightData* data) override {
+ return internal::ReadPayload(&*stream_, data);
+ }
+ Status WriteData(const FlightPayload& payload) override {
+ return internal::WritePayload(payload, stream_);
+ }
+
+ private:
+ grpc::ServerReaderWriter<pb::FlightData, pb::FlightData>* stream_;
+};
+
// This class glues an implementation of FlightServerBase together with the
// gRPC service definition, so the latter is not exposed in the public API
-class FlightServiceImpl : public FlightService::Service {
+class FlightGrpcServiceImpl : public FlightService::Service {
Review comment:
Renamed to GrpcServiceHandler
##########
File path: cpp/src/arrow/flight/transport_impl.h
##########
@@ -0,0 +1,220 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you 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.
+
+// Internal (but not private) interface for implementing alternate
+// transports in Flight.
+//
+// EXPERIMENTAL. Subject to change.
+
+#pragma once
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "arrow/flight/type_fwd.h"
+#include "arrow/flight/visibility.h"
+#include "arrow/type_fwd.h"
+
+namespace arrow {
+namespace ipc {
+class Message;
+}
+namespace flight {
+namespace internal {
+
+/// Internal, not user-visible type used for memory-efficient reads
+struct FlightData {
+ /// Used only for puts, may be null
+ std::unique_ptr<FlightDescriptor> descriptor;
+
+ /// Non-length-prefixed Message header as described in format/Message.fbs
+ std::shared_ptr<Buffer> metadata;
+
+ /// Application-defined metadata
+ std::shared_ptr<Buffer> app_metadata;
+
+ /// Message body
+ std::shared_ptr<Buffer> body;
+
+ /// Open IPC message from the metadata and body
+ ::arrow::Result<std::unique_ptr<ipc::Message>> OpenMessage();
+};
+
+/// \brief An transport-specific interface for reading/writing Arrow data.
+///
+/// New transports will implement this to read/write IPC payloads to
+/// the underlying stream.
+class ARROW_FLIGHT_EXPORT TransportDataStream {
+ public:
+ virtual ~TransportDataStream() = default;
+ /// \brief Attemnpt to read the next FlightData message.
+ ///
+ /// \return success true if data was populated, false if there was
+ /// an error. For clients, the error can be retrieved from Finish.
+ virtual bool ReadData(FlightData* data);
+ /// \brief Attempt to write a FlightPayload.
+ virtual Status WriteData(const FlightPayload& payload);
+ /// \brief Attempt to write a non-data message.
+ ///
+ /// Only implemented for DoPut; mutually exclusive with Write(const
+ /// FlightPayload&).
+ virtual Status WritePutMetadata(const Buffer& payload);
+ /// \brief Indicate that there are no more writes on this stream.
+ ///
+ /// This is only a hint for the underlying transport and may not
+ /// actually do anything.
+ virtual Status WritesDone();
+};
+
+/// \brief A transport-specific interface for reading/writing Arrow
+/// data for a client.
+class ARROW_FLIGHT_EXPORT ClientDataStream : public TransportDataStream {
+ public:
+ /// \brief Attempt to read a non-data message.
+ ///
+ /// Only implemented for DoPut; mutually exclusive with Read(FlightData*).
+ virtual bool ReadPutMetadata(std::shared_ptr<Buffer>* out);
+ /// \brief Finish the call, returning the final server status.
+ ///
+ /// Implies WritesDone().
+ virtual Status Finish() = 0;
+ /// \brief Attempt to cancel the call.
+ ///
+ /// This is only a hint and may not take effect immediately. The
+ /// client should still finish the call with Finish() as usual.
+ virtual void TryCancel() {}
+ /// \brief Finish the call, combining client-side status with server status.
+ Status Finish(Status st);
+};
+
+/// An implementation of a Flight client for a particular transport.
+///
+/// Transports should override the methods they are capable of
+/// supporting. The default method implementations return an error.
+class ARROW_FLIGHT_EXPORT ClientTransportImpl {
+ public:
+ virtual ~ClientTransportImpl() = default;
+
+ /// Initialize the client.
+ virtual Status Init(const FlightClientOptions& options, const Location&
location,
+ const arrow::internal::Uri& uri) = 0;
+ /// Close the client. Once this returns, the client is no longer usable.
+ virtual Status Close() = 0;
+
+ virtual Status Authenticate(const FlightCallOptions& options,
+ std::unique_ptr<ClientAuthHandler> auth_handler);
+ virtual arrow::Result<std::pair<std::string, std::string>>
AuthenticateBasicToken(
+ const FlightCallOptions& options, const std::string& username,
+ const std::string& password);
+ virtual Status DoAction(const FlightCallOptions& options, const Action&
action,
+ std::unique_ptr<ResultStream>* results);
+ virtual Status ListActions(const FlightCallOptions& options,
+ std::vector<ActionType>* actions);
+ virtual Status GetFlightInfo(const FlightCallOptions& options,
+ const FlightDescriptor& descriptor,
+ std::unique_ptr<FlightInfo>* info);
+ virtual Status GetSchema(const FlightCallOptions& options,
+ const FlightDescriptor& descriptor,
+ std::unique_ptr<SchemaResult>* schema_result);
+ virtual Status ListFlights(const FlightCallOptions& options, const Criteria&
criteria,
+ std::unique_ptr<FlightListing>* listing);
+ virtual Status DoGet(const FlightCallOptions& options, const Ticket& ticket,
+ std::unique_ptr<ClientDataStream>* stream);
+ virtual Status DoPut(const FlightCallOptions& options,
+ std::unique_ptr<ClientDataStream>* stream);
+ virtual Status DoExchange(const FlightCallOptions& options,
+ std::unique_ptr<ClientDataStream>* stream);
+};
+
+/// The implementation of the Flight service, which implements RPC
+/// method handlers that work in terms of the generic interfaces
+/// here.
+///
+/// Transport implementations should implement the necessary
+/// interfaces and call methods of this service.
+class ARROW_FLIGHT_EXPORT FlightServiceImpl {
+ public:
+ explicit FlightServiceImpl(FlightServerBase* base,
+ std::shared_ptr<MemoryManager> memory_manager)
+ : service_(base), memory_manager_(std::move(memory_manager)) {}
+ Status DoGet(const ServerCallContext& context, const Ticket& request,
+ TransportDataStream* stream);
+ Status DoPut(const ServerCallContext& context, TransportDataStream* stream);
+ Status DoExchange(const ServerCallContext& context, TransportDataStream*
stream);
+ FlightServerBase* base() const { return service_; }
+
+ private:
+ FlightServerBase* service_;
Review comment:
Whoops - renamed to base_ since that's the getter's name anyways.
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