AngersZhuuuu commented on a change in pull request #27983: URL: https://github.com/apache/spark/pull/27983#discussion_r451930832
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/script/ScriptTransformbase.scala ########## @@ -0,0 +1,167 @@ +/* + * 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.execution.script + +import java.io.OutputStream +import java.util.concurrent.TimeUnit + +import scala.util.control.NonFatal + +import org.apache.hadoop.conf.Configuration + +import org.apache.spark.{SparkException, TaskContext} +import org.apache.spark.internal.Logging +import org.apache.spark.rdd.RDD +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.catalyst.expressions.UnsafeProjection +import org.apache.spark.sql.execution.UnaryExecNode +import org.apache.spark.sql.internal.SQLConf +import org.apache.spark.sql.types.DataType +import org.apache.spark.util.{CircularBuffer, SerializableConfiguration, Utils} + +trait ScriptTransformBase extends UnaryExecNode { + override def doExecute(): RDD[InternalRow] = { + val broadcastedHadoopConf = + new SerializableConfiguration(sqlContext.sessionState.newHadoopConf()) + + child.execute().mapPartitions { iter => + if (iter.hasNext) { + val proj = UnsafeProjection.create(schema) + processIterator(iter, broadcastedHadoopConf.value).map(proj) + } else { + // If the input iterator has no rows then do not launch the external script. + Iterator.empty + } + } + } + + def processIterator( + inputIterator: Iterator[InternalRow], + hadoopConf: Configuration): Iterator[InternalRow] + + protected def checkFailureAndPropagate( + writerThread: ScriptTransformationWriterThreadBase, + cause: Throwable = null, + proc: Process, + stderrBuffer: CircularBuffer): Unit = { + if (writerThread.exception.isDefined) { + throw writerThread.exception.get + } + + // There can be a lag between reader read EOF and the process termination. + // If the script fails to startup, this kind of error may be missed. + // So explicitly waiting for the process termination. + val timeout = conf.getConf(SQLConf.SCRIPT_TRANSFORMATION_EXIT_TIMEOUT) + val exitRes = proc.waitFor(timeout, TimeUnit.SECONDS) + if (!exitRes) { + log.warn(s"Transformation script process exits timeout in $timeout seconds") + } + + if (!proc.isAlive) { + val exitCode = proc.exitValue() + if (exitCode != 0) { + logError(stderrBuffer.toString) // log the stderr circular buffer + throw new SparkException(s"Subprocess exited with status $exitCode. " + + s"Error: ${stderrBuffer.toString}", cause) + } + } + } +} + +abstract class ScriptTransformationWriterThreadBase( + iter: Iterator[InternalRow], + inputSchema: Seq[DataType], + outputStream: OutputStream, + proc: Process, + stderrBuffer: CircularBuffer, + taskContext: TaskContext, + conf: Configuration) extends Thread with Logging { + @volatile protected var _exception: Throwable = null + + /** Contains the exception thrown while writing the parent iterator to the external process. */ + def exception: Option[Throwable] = Option(_exception) + + protected def processRows(): Unit + + override def run(): Unit = Utils.logUncaughtExceptions { + TaskContext.setTaskContext(taskContext) + + // We can't use Utils.tryWithSafeFinally here because we also need a `catch` block, so + // let's use a variable to record whether the `finally` block was hit due to an exception + var threwException: Boolean = true + try { + processRows() + threwException = false + } catch { + // SPARK-25158 Exception should not be thrown again, otherwise it will be captured by + // SparkUncaughtExceptionHandler, then Executor will exit because of this Uncaught Exception, + // so pass the exception to `ScriptTransformationExec` is enough. + case t: Throwable => + // An error occurred while writing input, so kill the child process. According to the + // Javadoc this call will not throw an exception: + _exception = t + proc.destroy() + logError("Thread-ScriptTransformation-Feed exit cause by: ", t) + } finally { + try { + Utils.tryLogNonFatalError(outputStream.close()) + if (proc.waitFor() != 0) { + logError(stderrBuffer.toString) // log the stderr circular buffer + } + } catch { + case NonFatal(exceptionFromFinallyBlock) => + if (!threwException) { + throw exceptionFromFinallyBlock + } else { + log.error("Exception in finally block", exceptionFromFinallyBlock) + } + } + } + } +} + +/** + * The wrapper class of input and output schema properties + */ +abstract class ScriptTransformIOSchemaBase extends Serializable { + def inputRowFormat: Seq[(String, String)] + + def outputRowFormat: Seq[(String, String)] + + def inputSerdeClass: Option[String] + + def outputSerdeClass: Option[String] + + def inputSerdeProps: Seq[(String, String)] + + def outputSerdeProps: Seq[(String, String)] + + def recordReaderClass: Option[String] + + def recordWriterClass: Option[String] + + def schemaLess: Boolean + + protected val defaultFormat = Map( Review comment: > This is just a suggestion; how about pulling out this value outside like this? > > ``` > object ScriptIOSchema { > val defaultFormat = Map(...) > } > ``` default value pulling out seems reasonable. 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