[GitHub] [arrow] cyb70289 commented on a diff in pull request #12442: ARROW-15706: [C++][FlightRPC] Implement a UCX transport

[GitBox <gi...@apache.org>]

cyb70289 commented on code in PR #12442:
URL: https://github.com/apache/arrow/pull/12442#discussion_r841525350


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cpp/src/arrow/flight/transport/ucx/ucx_client.cc:
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@@ -0,0 +1,730 @@
+// 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.
+
+/// The client-side implementation of a UCX-based transport for
+/// Flight.
+///
+/// Each UCX driver is used to support one call at a time. This gives
+/// the greatest throughput for data plane methods, but is relatively
+/// expensive in terms of other resources, both for the server and the
+/// client. (UCX drivers have multiple threading modes: single-thread
+/// access, serialized access, and multi-thread access. Testing found
+/// that multi-thread access incurred high synchronization costs.)
+/// Hence, for concurrent calls in a single client, we must maintain
+/// multiple drivers, and so unlike gRPC, there is no real difference
+/// between using one client concurrently and using multiple
+/// independent clients.
+
+#include "arrow/flight/transport/ucx/ucx_internal.h"
+
+#include <condition_variable>
+#include <deque>
+#include <mutex>
+#include <thread>
+
+#include <arpa/inet.h>
+#include <ucp/api/ucp.h>
+
+#include "arrow/buffer.h"
+#include "arrow/flight/client.h"
+#include "arrow/flight/transport.h"
+#include "arrow/flight/transport/ucx/util_internal.h"
+#include "arrow/result.h"
+#include "arrow/status.h"
+#include "arrow/util/logging.h"
+#include "arrow/util/make_unique.h"
+#include "arrow/util/uri.h"
+
+namespace arrow {
+namespace flight {
+namespace transport {
+namespace ucx {
+
+namespace {
+class UcxClientImpl;
+
+Status MergeStatuses(Status server_status, Status transport_status) {
+  if (server_status.ok()) {
+    if (transport_status.ok()) return server_status;
+    return transport_status;
+  } else if (transport_status.ok()) {
+    return server_status;
+  }
+  return Status::FromDetailAndArgs(server_status.code(), server_status.detail(),
+                                   server_status.message(),
+                                   ". Transport context: ", transport_status.ToString());
+}
+
+/// \brief An individual connection to the server.
+class ClientConnection {
+ public:
+  ClientConnection() = default;
+  ARROW_DISALLOW_COPY_AND_ASSIGN(ClientConnection);
+  ARROW_DEFAULT_MOVE_AND_ASSIGN(ClientConnection);
+  ~ClientConnection() { DCHECK(!driver_) << "Connection was not closed!"; }
+
+  Status Init(std::shared_ptr<UcpContext> ucp_context, const arrow::internal::Uri& uri) {
+    auto status = InitImpl(std::move(ucp_context), uri);
+    // Clean up after-the-fact if we fail to initialize
+    if (!status.ok()) {
+      if (driver_) {
+        status = MergeStatuses(std::move(status), driver_->Close());
+        driver_.reset();
+        remote_endpoint_ = nullptr;
+      }
+      if (ucp_worker_) ucp_worker_.reset();
+    }
+    return status;
+  }
+
+  Status InitImpl(std::shared_ptr<UcpContext> ucp_context,
+                  const arrow::internal::Uri& uri) {
+    {
+      ucs_status_t status;
+      ucp_worker_params_t worker_params;
+      std::memset(&worker_params, 0, sizeof(worker_params));
+      worker_params.field_mask = UCP_WORKER_PARAM_FIELD_THREAD_MODE;
+      worker_params.thread_mode = UCS_THREAD_MODE_SERIALIZED;
+
+      ucp_worker_h ucp_worker;
+      status = ucp_worker_create(ucp_context->get(), &worker_params, &ucp_worker);
+      RETURN_NOT_OK(FromUcsStatus("ucp_worker_create", status));
+      ucp_worker_.reset(new UcpWorker(std::move(ucp_context), ucp_worker));
+    }
+    {
+      // Create endpoint for remote worker
+      struct sockaddr_storage connect_addr;
+      ARROW_ASSIGN_OR_RAISE(auto addrlen, UriToSockaddr(uri, &connect_addr));
+      std::string peer;
+      ARROW_UNUSED(SockaddrToString(connect_addr).Value(&peer));
+      ARROW_LOG(DEBUG) << "Connecting to " << peer;
+
+      ucp_ep_params_t params;
+      params.field_mask = UCP_EP_PARAM_FIELD_FLAGS | UCP_EP_PARAM_FIELD_NAME |
+                          UCP_EP_PARAM_FIELD_SOCK_ADDR;
+      params.flags = UCP_EP_PARAMS_FLAGS_CLIENT_SERVER;
+      params.name = "UcxClientImpl";
+      params.sockaddr.addr = reinterpret_cast<const sockaddr*>(&connect_addr);
+      params.sockaddr.addrlen = addrlen;
+
+      auto status = ucp_ep_create(ucp_worker_->get(), &params, &remote_endpoint_);
+      RETURN_NOT_OK(FromUcsStatus("ucp_ep_create", status));
+    }
+
+    driver_.reset(new UcpCallDriver(ucp_worker_, remote_endpoint_));
+    ARROW_LOG(DEBUG) << "Connected to " << driver_->peer();
+
+    {
+      // Set up Active Message (AM) handler
+      ucp_am_handler_param_t handler_params;
+      handler_params.field_mask = UCP_AM_HANDLER_PARAM_FIELD_ID |
+                                  UCP_AM_HANDLER_PARAM_FIELD_CB |
+                                  UCP_AM_HANDLER_PARAM_FIELD_ARG;
+      handler_params.id = kUcpAmHandlerId;
+      handler_params.cb = HandleIncomingActiveMessage;
+      handler_params.arg = driver_.get();
+      ucs_status_t status =
+          ucp_worker_set_am_recv_handler(ucp_worker_->get(), &handler_params);
+      RETURN_NOT_OK(FromUcsStatus("ucp_worker_set_am_recv_handler", status));
+    }
+
+    return Status::OK();
+  }
+
+  Status Close() {
+    if (!driver_) return Status::OK();
+
+    auto status = driver_->SendFrame(FrameType::kDisconnect, nullptr, 0);
+    const auto ucs_status = FlightUcxStatusDetail::Unwrap(status);
+    if (IsIgnorableDisconnectError(ucs_status)) {
+      status = Status::OK();
+    }
+    status = MergeStatuses(std::move(status), driver_->Close());
+
+    driver_.reset();
+    remote_endpoint_ = nullptr;
+    ucp_worker_.reset();
+    return status;
+  }
+
+  UcpCallDriver* driver() {
+    DCHECK(driver_);
+    return driver_.get();
+  }
+
+ private:
+  static ucs_status_t HandleIncomingActiveMessage(void* self, const void* header,
+                                                  size_t header_length, void* data,
+                                                  size_t data_length,
+                                                  const ucp_am_recv_param_t* param) {
+    auto* driver = reinterpret_cast<UcpCallDriver*>(self);
+    return driver->RecvActiveMessage(header, header_length, data, data_length, param);
+  }
+
+  std::shared_ptr<UcpWorker> ucp_worker_;
+  ucp_ep_h remote_endpoint_;
+  std::unique_ptr<UcpCallDriver> driver_;
+};
+
+class UcxClientStream : public internal::ClientDataStream {
+ public:
+  UcxClientStream(UcxClientImpl* impl, ClientConnection conn)
+      : impl_(impl),
+        conn_(std::move(conn)),
+        driver_(conn_.driver()),
+        writes_done_(false),
+        finished_(false) {}
+
+ protected:
+  Status DoFinish() override;
+
+  UcxClientImpl* impl_;
+  ClientConnection conn_;
+  UcpCallDriver* driver_;
+  bool writes_done_;
+  bool finished_;
+  Status io_status_;
+  Status server_status_;
+};
+
+class GetClientStream : public UcxClientStream {
+ public:
+  GetClientStream(UcxClientImpl* impl, ClientConnection conn)
+      : UcxClientStream(impl, std::move(conn)) {
+    writes_done_ = true;
+  }
+
+  bool ReadData(internal::FlightData* data) override {
+    if (finished_) return false;
+
+    bool success = true;
+    io_status_ = ReadImpl(data).Value(&success);
+
+    if (!io_status_.ok() || !success) {
+      finished_ = true;
+    }
+    return success;
+  }
+
+ private:
+  ::arrow::Result<bool> ReadImpl(internal::FlightData* data) {
+    ARROW_ASSIGN_OR_RAISE(auto frame, driver_->ReadNextFrame());
+
+    if (frame->type == FrameType::kHeaders) {
+      // Trailers, stream is over
+      ARROW_ASSIGN_OR_RAISE(auto headers, HeadersFrame::Parse(std::move(frame->buffer)));
+      RETURN_NOT_OK(headers.GetStatus(&server_status_));
+      return false;
+    }
+
+    RETURN_NOT_OK(driver_->ExpectFrameType(*frame, FrameType::kPayloadHeader));
+    PayloadHeaderFrame payload_header(std::move(frame->buffer));
+    RETURN_NOT_OK(payload_header.ToFlightData(data));
+
+    // DoGet does not support metadata-only messages, so we can always
+    // assume we have an IPC payload
+    ARROW_ASSIGN_OR_RAISE(auto message, ipc::Message::Open(data->metadata, nullptr));
+
+    if (ipc::Message::HasBody(message->type())) {
+      ARROW_ASSIGN_OR_RAISE(frame, driver_->ReadNextFrame());
+      RETURN_NOT_OK(driver_->ExpectFrameType(*frame, FrameType::kPayloadBody));
+      data->body = std::move(frame->buffer);
+    }
+    return true;
+  }
+};
+
+class WriteClientStream : public UcxClientStream {
+ public:
+  WriteClientStream(UcxClientImpl* impl, ClientConnection conn)
+      : UcxClientStream(impl, std::move(conn)) {
+    std::thread t(&WriteClientStream::DriveWorker, this);
+    driver_thread_.swap(t);
+  }
+  arrow::Result<bool> WriteData(const FlightPayload& payload) override {
+    std::unique_lock<std::mutex> guard(driver_mutex_);
+    if (finished_ || writes_done_) return Status::Invalid("Already done writing");
+    outgoing_ = driver_->SendFlightPayload(payload);
+    working_cv_.notify_all();
+    received_cv_.wait(guard, [this] { return outgoing_.is_finished(); });
+
+    auto status = outgoing_.status();
+    outgoing_ = Future<>();
+    RETURN_NOT_OK(status);
+    return true;
+  }
+  Status WritesDone() override {
+    std::unique_lock<std::mutex> guard(driver_mutex_);
+    if (!writes_done_) {
+      ARROW_ASSIGN_OR_RAISE(auto headers, HeadersFrame::Make({}));
+      outgoing_ =
+          driver_->SendFrameAsync(FrameType::kHeaders, std::move(headers).GetBuffer());
+      working_cv_.notify_all();
+      received_cv_.wait(guard, [this] { return outgoing_.is_finished(); });
+
+      writes_done_ = true;
+      auto status = outgoing_.status();
+      outgoing_ = Future<>();
+      RETURN_NOT_OK(status);
+    }
+    return Status::OK();
+  }
+
+ protected:
+  void JoinThread() {
+    try {
+      driver_thread_.join();
+    } catch (const std::system_error&) {
+      // Ignore
+    }
+  }
+  void DriveWorker() {

Review Comment:
   Are the ucx callbacks (`AmSendCallback`, `HandleIncomingActiveMessage`) invoked inside `ucp_wroker_progress()`?



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