/
EventLogFileCompactor.scala
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/
EventLogFileCompactor.scala
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/*
* 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.deploy.history
import java.io.IOException
import java.net.URI
import java.util.ServiceLoader
import scala.collection.JavaConverters._
import org.apache.hadoop.conf.Configuration
import org.apache.hadoop.fs.{FileStatus, FileSystem, Path}
import org.apache.spark.SparkConf
import org.apache.spark.deploy.history.EventFilter.FilterStatistics
import org.apache.spark.internal.Logging
import org.apache.spark.internal.config.{EVENT_LOG_COMPACTION_SCORE_THRESHOLD, EVENT_LOG_ROLLING_MAX_FILES_TO_RETAIN}
import org.apache.spark.scheduler.ReplayListenerBus
import org.apache.spark.util.Utils
/**
* This class compacts the old event log files into one compact file, via two phases reading:
*
* 1) Initialize available [[EventFilterBuilder]] instances, and replay the old event log files with
* builders, so that these builders can gather the information to create [[EventFilter]] instances.
* 2) Initialize [[EventFilter]] instances from [[EventFilterBuilder]] instances, and replay the
* old event log files with filters. Rewrite the events to the compact file which the filters decide
* to accept.
*
* This class will calculate the score based on statistic from [[EventFilter]] instances, which
* represents approximate rate of filtered-out events. Score is being calculated via applying
* heuristic; task events tend to take most size in event log.
*/
class EventLogFileCompactor(
sparkConf: SparkConf,
hadoopConf: Configuration,
fs: FileSystem) extends Logging {
private val maxFilesToRetain: Int = sparkConf.get(EVENT_LOG_ROLLING_MAX_FILES_TO_RETAIN)
private val compactionThresholdScore: Double = sparkConf.get(EVENT_LOG_COMPACTION_SCORE_THRESHOLD)
/**
* Compacts the old event log files into one compact file, and clean old event log files being
* compacted away.
*
* This method assumes caller will provide the sorted list of files which are sorted by
* the index of event log file, with at most one compact file placed first if it exists.
*
* When compacting the files, the range of compaction for given file list is determined as:
* (first ~ the file where there're `maxFilesToRetain` files on the right side)
*
* This method skips compaction for some circumstances described below:
* - not enough files on the range of compaction
* - score is lower than the threshold of compaction (meaning compaction won't help much)
*
* If this method returns the compaction result as SUCCESS, caller needs to re-read the list
* of event log files, as new compact file is available as well as old event log files are
* removed.
*/
def compact(eventLogFiles: Seq[FileStatus]): CompactionResult = {
assertPrecondition(eventLogFiles)
if (eventLogFiles.length < maxFilesToRetain) {
return CompactionResult(CompactionResultCode.NOT_ENOUGH_FILES, None)
}
val filesToCompact = findFilesToCompact(eventLogFiles)
if (filesToCompact.isEmpty) {
CompactionResult(CompactionResultCode.NOT_ENOUGH_FILES, None)
} else {
val builders = initializeBuilders(fs, filesToCompact.map(_.getPath))
val filters = builders.map(_.createFilter())
val minScore = filters.flatMap(_.statistics()).map(calculateScore).min
if (minScore < compactionThresholdScore) {
CompactionResult(CompactionResultCode.LOW_SCORE_FOR_COMPACTION, None)
} else {
rewrite(filters, filesToCompact)
cleanupCompactedFiles(filesToCompact)
CompactionResult(CompactionResultCode.SUCCESS, Some(
RollingEventLogFilesWriter.getEventLogFileIndex(filesToCompact.last.getPath.getName)))
}
}
}
private def assertPrecondition(eventLogFiles: Seq[FileStatus]): Unit = {
val idxCompactedFiles = eventLogFiles.zipWithIndex.filter { case (file, _) =>
EventLogFileWriter.isCompacted(file.getPath)
}
require(idxCompactedFiles.size < 2 && idxCompactedFiles.headOption.forall(_._2 == 0),
"The number of compact files should be at most 1, and should be placed first if exists.")
}
/**
* Loads all available EventFilterBuilders in classloader via ServiceLoader, and initializes
* them via replaying events in given files.
*/
private def initializeBuilders(fs: FileSystem, files: Seq[Path]): Seq[EventFilterBuilder] = {
val bus = new ReplayListenerBus()
val builders = ServiceLoader.load(classOf[EventFilterBuilder],
Utils.getContextOrSparkClassLoader).asScala.toSeq
builders.foreach(bus.addListener)
files.foreach { log =>
Utils.tryWithResource(EventLogFileReader.openEventLog(log, fs)) { in =>
bus.replay(in, log.getName)
}
}
builders
}
private def calculateScore(stats: FilterStatistics): Double = {
// For now it's simply measuring how many task events will be filtered out (rejected)
// but it can be sophisticated later once we get more heuristic information and found
// the case where this simple calculation doesn't work.
(stats.totalTasks - stats.liveTasks) * 1.0 / stats.totalTasks
}
/**
* This method rewrites the event log files into one compact file: the compact file will only
* contain the events which pass the filters. Events will be dropped only when all filters
* decide to reject the event or don't mind about the event. Otherwise, the original line for
* the event is written to the compact file as it is.
*/
private[history] def rewrite(
filters: Seq[EventFilter],
eventLogFiles: Seq[FileStatus]): String = {
require(eventLogFiles.nonEmpty)
val lastIndexEventLogPath = eventLogFiles.last.getPath
val logWriter = new CompactedEventLogFileWriter(lastIndexEventLogPath, "dummy", None,
lastIndexEventLogPath.getParent.toUri, sparkConf, hadoopConf)
logWriter.start()
eventLogFiles.foreach { file =>
EventFilter.applyFilterToFile(fs, filters, file.getPath,
onAccepted = (line, _) => logWriter.writeEvent(line, flushLogger = true),
onRejected = (_, _) => {},
onUnidentified = line => logWriter.writeEvent(line, flushLogger = true)
)
}
logWriter.stop()
logWriter.logPath
}
private def cleanupCompactedFiles(files: Seq[FileStatus]): Unit = {
files.foreach { file =>
var deleted = false
try {
deleted = fs.delete(file.getPath, true)
} catch {
case _: IOException =>
}
if (!deleted) {
logWarning(s"Failed to remove ${file.getPath} / skip removing.")
}
}
}
private def findFilesToCompact(eventLogFiles: Seq[FileStatus]): Seq[FileStatus] = {
val numNormalEventLogFiles = {
if (EventLogFileWriter.isCompacted(eventLogFiles.head.getPath)) {
eventLogFiles.length - 1
} else {
eventLogFiles.length
}
}
// This avoids compacting only compact file.
if (numNormalEventLogFiles > maxFilesToRetain) {
eventLogFiles.dropRight(maxFilesToRetain)
} else {
Seq.empty
}
}
}
/**
* Describes the result of compaction.
*
* @param code The result of compaction.
* @param compactIndex The index of compact file if the compaction is successful.
* Otherwise it will be None.
*/
case class CompactionResult(code: CompactionResultCode.Value, compactIndex: Option[Long])
object CompactionResultCode extends Enumeration {
val SUCCESS, NOT_ENOUGH_FILES, LOW_SCORE_FOR_COMPACTION = Value
}
/**
* This class helps to write compact file; to avoid reimplementing everything, it extends
* [[SingleEventLogFileWriter]], but only `originalFilePath` is used to determine the
* path of compact file.
*/
private class CompactedEventLogFileWriter(
originalFilePath: Path,
appId: String,
appAttemptId: Option[String],
logBaseDir: URI,
sparkConf: SparkConf,
hadoopConf: Configuration)
extends SingleEventLogFileWriter(appId, appAttemptId, logBaseDir, sparkConf, hadoopConf) {
override val logPath: String = originalFilePath.toUri.toString + EventLogFileWriter.COMPACTED
}