Copilot commented on code in PR #50407:
URL: https://github.com/apache/arrow/pull/50407#discussion_r4208017066
##########
cpp/src/arrow/flight/server.h:
##########
@@ -195,10 +195,9 @@ class ARROW_FLIGHT_EXPORT FlightServerBase {
Status Init(const FlightServerOptions& options);
/// \brief Get the port that the Flight server is listening on.
- /// This method must only be called after Init(). Will return a
- /// non-positive value if no port exists (e.g. when listening on a
- /// domain socket).
- int port() const;
+ /// This method must only be called after Init().
+ /// \return Arrow result with the port number, or an error if it cannot be
determined.
+ arrow::Result<int> port() const;
Review Comment:
This changes the public return type from `int` to `Result<int>`, but the
in-tree callers still stream, compare, stringify, and pass `server->port()` as
an `int` (for example `flight/flight_test.cc:215`, `flight/test_util.h:89`, and
`flight/test_definitions.cc:116`). `Result` has no implicit conversion, so this
change does not compile without updating all callers (or preserving the
existing API and adding a separate error-returning method).
##########
cpp/src/arrow/flight/transport/grpc/util_internal.h:
##########
@@ -51,6 +35,12 @@ class Status;
namespace flight {
+#define GRPC_CPP_VERSION_CHECK(major, minor, patch)
\
+ ((GRPC_CPP_VERSION_MAJOR > (major) ||
\
+ (GRPC_CPP_VERSION_MAJOR == (major) && GRPC_CPP_VERSION_MINOR > (minor)) ||
\
+ ((GRPC_CPP_VERSION_MAJOR == (major) && GRPC_CPP_VERSION_MINOR == (minor)
&& \
+ GRPC_CPP_VERSION_PATCH >= (patch)))))
Review Comment:
These macros are now expanded without checking that `GRPC_CPP_VERSION_*`
exists. `util_internal.h` is included before `<grpcpp/grpcpp.h>` in
`util_internal.cc` and directly from `server_tracing_middleware.cc`, so
supported gRPC versions/translation units where the version macros are not
transitively defined will fail preprocessing; the previous guard handled this.
Restore the fallback definition for older or missing gRPC version macros.
This issue also appears on line 100 of the same file.
##########
cpp/src/arrow/flight/transport_server.h:
##########
@@ -21,6 +21,7 @@
#include <memory>
#include "arrow/flight/transport.h"
+#include "arrow/flight/transport_server_internal.h"
Review Comment:
`transport_server.h` is a public header, but `ARROW_INSTALL_ALL_HEADERS`
deliberately excludes headers whose basename contains `internal`
(`cmake_modules/BuildUtils.cmake:960-962`). Consequently installed consumers
include this file and fail because `arrow/flight/transport_server_internal.h`
is not installed. The internal header is not needed for the public
declarations, so remove this include and include it only from the
implementation files.
##########
cpp/src/arrow/flight/transport_server_internal.h:
##########
@@ -0,0 +1,275 @@
+// 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.
+
+#pragma once
+
+#include <atomic>
+#include <chrono>
+#include <memory>
+#include <thread>
+#include <utility>
+#include <vector>
+
+#include "arrow/flight/platform.h"
+#include "arrow/flight/server.h"
+#include "arrow/flight/visibility.h"
+#include "arrow/result.h"
+#include "arrow/status.h"
+#include "arrow/util/io_util.h"
+#include "arrow/util/logging.h"
+#include "arrow/util/uri.h"
Review Comment:
`transport_server.h` includes this header, but the declarations below use
`ipc::ReadStats` and `ipc::WriteStats` without including headers that declare
those structs. `server.h` only brings in `ipc/type_fwd.h`, which does not
declare either struct, so consumers of `transport_server.h` will fail with
unknown-type errors. Include `arrow/ipc/reader.h` and `arrow/ipc/writer.h` here
(or add suitable declarations).
##########
cpp/src/arrow/flight/transport_server_internal.h:
##########
@@ -0,0 +1,275 @@
+// 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.
+
+#pragma once
+
+#include <atomic>
+#include <chrono>
+#include <memory>
+#include <thread>
+#include <utility>
+#include <vector>
+
+#include "arrow/flight/platform.h"
+#include "arrow/flight/server.h"
+#include "arrow/flight/visibility.h"
+#include "arrow/result.h"
+#include "arrow/status.h"
+#include "arrow/util/io_util.h"
+#include "arrow/util/logging.h"
+#include "arrow/util/uri.h"
+
+namespace arrow::flight::internal {
+
+class ServerDataStream;
+class PeekableFlightDataReader;
+
+/// \brief Adapt TransportDataStream to the FlightMessageReader
+/// interface for DoPut.
+class TransportMessageReader final : public FlightMessageReader {
+ public:
+ TransportMessageReader(ServerDataStream* stream,
+ std::shared_ptr<MemoryManager> memory_manager);
+
+ Status Init();
+
+ const FlightDescriptor& descriptor() const override;
+
+ arrow::Result<std::shared_ptr<Schema>> GetSchema() override;
+
+ arrow::Result<FlightStreamChunk> Next() override;
+
+ ipc::ReadStats stats() const override;
+
+ private:
+ /// Ensure we are set up to read data.
+ Status EnsureDataStarted();
+
+ FlightDescriptor descriptor_;
+ std::shared_ptr<PeekableFlightDataReader> peekable_reader_;
+ std::shared_ptr<MemoryManager> memory_manager_;
+ std::shared_ptr<ipc::RecordBatchStreamReader> batch_reader_;
+ std::shared_ptr<Buffer> app_metadata_;
+};
+
+/// \brief A writer for IPC payloads to a ServerDataStream.
+class TransportMessageWriter final : public FlightMessageWriter {
+ public:
+ explicit TransportMessageWriter(ServerDataStream* stream);
+
+ Status Begin(const std::shared_ptr<Schema>& schema,
+ const ipc::IpcWriteOptions& options) override;
+
+ Status WriteRecordBatch(const RecordBatch& batch) override;
+
+ Status WriteMetadata(std::shared_ptr<Buffer> app_metadata) override;
+
+ Status WriteWithMetadata(const RecordBatch& batch,
+ std::shared_ptr<Buffer> app_metadata) override;
+
+ Status Close() override;
+
+ ipc::WriteStats stats() const override;
+
+ private:
+ Status CheckStarted();
+
+ ServerDataStream* stream_;
+ std::unique_ptr<ipc::RecordBatchWriter> batch_writer_;
+ std::shared_ptr<Buffer> app_metadata_;
+ ::arrow::ipc::IpcWriteOptions ipc_options_;
+};
+
+/// \brief A writer for application-defined metadata to a ServerDataStream.
+class TransportMetadataWriter final : public FlightMetadataWriter {
+ public:
+ explicit TransportMetadataWriter(ServerDataStream* stream);
+
+ Status WriteMetadata(const Buffer& buffer) override;
+
+ private:
+ ServerDataStream* stream_;
+};
+
+/// \brief Write a FlightDataStream to a transport-level stream.
+///
+/// Used by DoGet and DoExchange to stream results back to the client.
+/// The schema is written first, followed by record batches until the
+/// stream is exhausted.
+///
+/// \param[in] data_stream The Arrow data stream to read from.
+/// \param[in] stream The transport-specific data stream to write to.
+Status WriteDataStream(std::unique_ptr<FlightDataStream> data_stream,
+ ServerDataStream* stream);
+
+/// \brief Manages a background thread that waits for OS signals.
+///
+/// Creates a signal-safe SelfPipe and spawns a thread that blocks on it.
+/// When a signal is received, the signal handler writes to the SelfPipe
+/// to wake the thread. The destructor ensures the thread is joined.
+class ServerSignalHandler {
+ public:
+ ARROW_DISALLOW_COPY_AND_ASSIGN(ServerSignalHandler);
+ ServerSignalHandler() = default;
+
+ /// \brief Initialize the signal handler and start the background thread.
+ ///
+ /// \param[in] handler A callable that will be invoked on the background
+ /// thread, receiving the SelfPipe as an argument.
+ /// \return The SelfPipe, which can be used to signal the handler thread.
+ template <typename Fn>
+ arrow::Result<std::shared_ptr<::arrow::internal::SelfPipe>> Init(Fn handler)
{
+ ARROW_ASSIGN_OR_RAISE(self_pipe_,
+
::arrow::internal::SelfPipe::Make(/*signal_safe=*/true));
+ handle_signals_ = std::thread(handler, self_pipe_);
+ return self_pipe_;
+ }
+
+ /// \brief Shut down the signal handler and join the background thread.
+ Status Shutdown() {
+ RETURN_NOT_OK(self_pipe_->Shutdown());
+ handle_signals_.join();
+ return Status::OK();
+ }
+
+ ~ServerSignalHandler() { ARROW_CHECK_OK(Shutdown()); }
+
+ private:
+ std::shared_ptr<::arrow::internal::SelfPipe> self_pipe_;
+ std::thread handle_signals_;
+};
+
+/// \brief Manages signal-driven graceful shutdown for server transports.
+///
+/// Installs signal handlers for the given set of signals. When a signal is
+/// received, the registered shutdown callback is invoked. Uses a SelfPipe
+/// to safely bridge the signal handler (which runs in a restricted context)
+/// to a background thread that performs the actual shutdown.
+class ARROW_FLIGHT_EXPORT ServerSignalState {
+ public:
+ ServerSignalState() = default;
+
+ /// \brief Configure which signals should trigger shutdown.
+ ///
+ /// \param[in] sigs List of signal numbers (e.g. SIGINT, SIGTERM).
+ Status SetShutdownOnSignals(const std::vector<int>& sigs);
+ /// \brief Return the last signal that was received, or 0 if none.
+ int GotSignal() const;
+
+ /// \brief Run the server with signal-aware lifecycle management.
+ ///
+ /// Installs signal handlers, calls \p wait (which should block until the
+ /// server stops), and restores original signal handlers on return.
+ /// If a signal is received during \p wait, \p shutdown is called first.
+ ///
+ /// \param[in] wait A callable that blocks until the server stops.
+ /// \param[in] shutdown A callable invoked on signal receipt to stop the
server.
+ /// \param[in] not_started_message Logged if shutdown is called before the
server
+ /// starts. \param[in] shutdown_warning Logged if shutdown itself fails.
+ template <typename WaitFn, typename ShutdownFn>
+ Status Serve(WaitFn&& wait, ShutdownFn&& shutdown, const char*
not_started_message,
+ const char* shutdown_warning) {
+ got_signal_ = 0;
+ old_signal_handlers_.clear();
+ running_instance_ = this;
+
+ ServerSignalHandler signal_handler;
+ ARROW_ASSIGN_OR_RAISE(self_pipe_,
+
signal_handler.Init(&ServerSignalState::WaitForSignals));
+ for (size_t i = 0; i < signals_.size(); ++i) {
+ int signum = signals_[i];
+ ::arrow::internal::SignalHandler
new_handler(&ServerSignalState::HandleSignal),
+ old_handler;
+ ARROW_ASSIGN_OR_RAISE(old_handler,
+ ::arrow::internal::SetSignalHandler(signum,
new_handler));
+ old_signal_handlers_.push_back(std::move(old_handler));
+ }
+
+ shutdown_ = [shutdown = std::forward<ShutdownFn>(shutdown)]() mutable {
+ return shutdown(nullptr);
+ };
+ shutdown_warning_ = shutdown_warning;
Review Comment:
The signal thread is started at line 192 and signal handlers are installed
before `shutdown_` is assigned here. If a registered signal arrives in that
window, `WaitForSignals` consumes the wakeup while observing a null callback,
then `Serve()` waits forever because the signal has been lost. Initialize the
shutdown callback before starting/installing signal handling, or make the
waiter synchronize with callback setup.
This issue also appears on line 213 of the same file.
##########
cpp/src/arrow/flight/types.h:
##########
@@ -564,6 +564,16 @@ struct ARROW_FLIGHT_EXPORT Location : public
internal::BaseType<Location> {
/// Use `Deserialize(serialized)` if you want a Result-returning version.
static arrow::Status Deserialize(std::string_view serialized, Location* out);
+ /// \brief Get the URI representation of this location.
+ ///
+ /// \return Arrow result with the URI.
+ arrow::Result<arrow::util::Uri> uri() const;
Review Comment:
`types.h` only forward-declares `arrow::util::Uri`, but `arrow::Result<T>`
embeds `AlignedStorage<T>` and therefore needs `T` complete when this return
type is instantiated. Including this public header now fails because
`Result<arrow::util::Uri>` requires `sizeof(Uri)`; include `arrow/util/uri.h`
in `types.h` rather than relying on the implementation file.
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