JiaqiWang18 commented on code in PR #51956: URL: https://github.com/apache/spark/pull/51956#discussion_r2317401778
########## sql/connect/server/src/main/scala/org/apache/spark/sql/connect/pipelines/PipelineEventSender.scala: ########## @@ -0,0 +1,185 @@ +/* + * 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. + */ + +package org.apache.spark.sql.connect.pipelines + +import java.util.concurrent.ThreadPoolExecutor +import java.util.concurrent.atomic.AtomicBoolean + +import scala.util.control.NonFatal + +import com.google.protobuf.{Timestamp => ProtoTimestamp} +import io.grpc.stub.StreamObserver + +import org.apache.spark.connect.proto +import org.apache.spark.connect.proto.ExecutePlanResponse +import org.apache.spark.internal.{Logging, LogKeys} +import org.apache.spark.sql.connect.service.SessionHolder +import org.apache.spark.sql.internal.SQLConf +import org.apache.spark.sql.pipelines.common.FlowStatus +import org.apache.spark.sql.pipelines.logging.{FlowProgress, PipelineEvent, RunProgress} +import org.apache.spark.util.ThreadUtils + +/** + * Handles sending pipeline events to the client in a background thread. This prevents pipeline + * execution from blocking on streaming events. + */ +class PipelineEventSender( + responseObserver: StreamObserver[ExecutePlanResponse], + sessionHolder: SessionHolder) + extends Logging + with AutoCloseable { + + private final val queueCapacity: Int = + sessionHolder.session.conf + .get(SQLConf.PIPELINES_EVENT_QUEUE_CAPACITY.key) + .toInt + + // ExecutorService for background event processing + private val executor: ThreadPoolExecutor = + ThreadUtils.newDaemonSingleThreadExecutor(threadName = + s"PipelineEventSender-${sessionHolder.sessionId}") + + /* + * Atomic flags to track the state of the sender + * - `isShutdown`: Indicates if the sender has been shut down, if true, no new events + * can be accepted, and the executor will be shut down after processing all submitted events. + */ + private val isShutdown = new AtomicBoolean(false) + + /** + * Send an event async by submitting it to the executor, if the sender is not shut down. + * Otherwise, throws an IllegalStateException, to raise awareness of the shutdown state. + * + * For RunProgress events, we ensure they are always queued even if the queue is full. For other + * events, we may drop them if the queue is at capacity to prevent blocking. + */ + def sendEvent(event: PipelineEvent): Unit = synchronized { + if (!isShutdown.get()) { + if (shouldEnqueueEvent(event)) { + executor.submit(new Runnable { + override def run(): Unit = { + try { + sendEventToClient(event) + } catch { + case NonFatal(e) => + logError( + log"Failed to send pipeline event to client: " + + log"${MDC(LogKeys.ERROR, event.message)}", + e) + } + } + }) + } + } else { + throw new IllegalStateException( + s"Cannot send event after shutdown for session ${sessionHolder.sessionId}") + } + } + + private def shouldEnqueueEvent(event: PipelineEvent): Boolean = { + event.details match { + case _: RunProgress => + // For RunProgress events, always enqueue event + true + case flowProgress: FlowProgress if FlowStatus.isTerminal(flowProgress.status) => + // For FlowProgress events that are terminal, always enqueue event + true + case _ => + // For other events, check if we have capacity + executor.getQueue.size() < queueCapacity + } + } + + // Implementing AutoCloseable to allow for try-with-resources usage + // This will ensure that the sender is properly shut down and all resources are released + // without requiring explicit shutdown calls in user code. + override def close(): Unit = shutdown() + + /** + * Shutdown the event sender, stop taking new events and wait for processing to complete. This + * method blocks until all queued events have been processed. Idempotent operation: calling this + * multiple times has no effect after the first call. + */ + def shutdown(): Unit = { + if (isShutdown.compareAndSet(false, true)) { + // Request a shutdown of the executor which waits for all tasks to complete + executor.shutdown() + // Blocks until all tasks have completed execution after a shutdown request, + // disregard the timeout since we want all events to be processed + if (!executor.awaitTermination(Long.MaxValue, java.util.concurrent.TimeUnit.MILLISECONDS)) { + logError( + log"Pipeline event sender for session " + + log"${MDC(LogKeys.SESSION_ID, sessionHolder.sessionId)} failed to terminate") + executor.shutdownNow() + } + logInfo( + log"Pipeline event sender shutdown completed for session " + + log"${MDC(LogKeys.SESSION_ID, sessionHolder.sessionId)}") + } + } + + /** + * Send a single event to the client + */ + private[connect] def sendEventToClient(event: PipelineEvent): Unit = { + try { + val message = if (event.error.nonEmpty) { + // Returns the message associated with a Throwable and all its causes + def getExceptionMessages(throwable: Throwable): Seq[String] = { + throwable.getMessage +: + Option(throwable.getCause).map(getExceptionMessages).getOrElse(Nil) + } + val errorMessages = getExceptionMessages(event.error.get) + s"""${event.message} + |Error: ${errorMessages.mkString("\n")}""".stripMargin + } else { + event.message + } + responseObserver.onNext( + proto.ExecutePlanResponse + .newBuilder() + .setSessionId(sessionHolder.sessionId) + .setServerSideSessionId(sessionHolder.serverSessionId) + .setPipelineEventResult( + proto.PipelineEventResult.newBuilder + .setEvent( + proto.PipelineEvent + .newBuilder() + .setTimestamp( + ProtoTimestamp + .newBuilder() + // java.sql.Timestamp normalizes its internal fields: getTime() returns + // the full timestamp in milliseconds, while getNanos() returns the + // fractional seconds (0-999,999,999 ns). This ensures no precision is + // lost or double-counted. + .setSeconds(event.timestamp.getTime / 1000) + .setNanos(event.timestamp.getNanos) + .build()) Review Comment: @gengliangwang extracted a helper [constructProtoEvent](https://github.com/apache/spark/pull/51956/commits/2bf017c1290470ccf3d94816dc851f07c00b3620) to reduce the nesting -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
