[SPARK-28869][CORE] Roll over event log files

### What changes were proposed in this pull request?

This patch is a part of [SPARK-28594](https://issues.apache.org/jira/browse/SPARK-28594) and design doc for SPARK-28594 is linked here: https://docs.google.com/document/d/12bdCC4nA58uveRxpeo8k7kGOI2NRTXmXyBOweSi4YcY/edit?usp=sharing

This patch proposes adding new feature to event logging, rolling event log files via configured file size.

Previously event logging is done with single file and related codebase (`EventLoggingListener`/`FsHistoryProvider`) is tightly coupled with it. This patch adds layer on both reader (`EventLogFileReader`) and writer (`EventLogFileWriter`) to decouple implementation details between "handling events" and "how to read/write events from/to file".

This patch adds two properties, `spark.eventLog.rollLog` and `spark.eventLog.rollLog.maxFileSize` which provides configurable behavior of rolling log. The feature is disabled by default, as we only expect huge event log for huge/long-running application. For other cases single event log file would be sufficient and still simpler.

### Why are the changes needed?

This is a part of SPARK-28594 which addresses event log growing infinitely for long-running application.

This patch itself also provides some option for the situation where event log file gets huge and consume their storage. End users may give up replaying their events and want to delete the event log file, but given application is still running and writing the file, it's not safe to delete the file. End users will be able to delete some of old files after applying rolling over event log.

### Does this PR introduce any user-facing change?

No, as the new feature is turned off by default.

### How was this patch tested?

Added unit tests, as well as basic manual tests.

Basic manual tests - ran SHS, ran structured streaming query with roll event log enabled, verified split files are generated as well as SHS can load these files, with handling app status as incomplete/complete.

Closes #25670 from HeartSaVioR/SPARK-28869.

Lead-authored-by: Jungtaek Lim (HeartSaVioR) <[email protected]>
Co-authored-by: Jungtaek Lim (HeartSaVioR) <[email protected]>
Signed-off-by: Marcelo Vanzin <[email protected]>

core/src/main/scala/org/apache/spark/deploy/history/EventLogFileReaders.scala

@@ -0,0 +1,264 @@
+/*
+ * 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.{BufferedInputStream, InputStream}
+import java.util.concurrent.ConcurrentHashMap
+import java.util.zip.{ZipEntry, ZipOutputStream}
+
+import com.google.common.io.ByteStreams
+import org.apache.hadoop.fs.{FileStatus, FileSystem, Path}
+import org.apache.hadoop.hdfs.DFSInputStream
+
+import org.apache.spark.SparkConf
+import org.apache.spark.deploy.history.EventLogFileWriter.codecName
+import org.apache.spark.io.CompressionCodec
+import org.apache.spark.util.Utils
+
+/** The base class of reader which will read the information of event log file(s). */
+abstract class EventLogFileReader(
+    protected val fileSystem: FileSystem,
+    val rootPath: Path) {
+
+  protected def fileSizeForDFS(path: Path): Option[Long] = {
+    Utils.tryWithResource(fileSystem.open(path)) { in =>
+      in.getWrappedStream match {
+        case dfsIn: DFSInputStream => Some(dfsIn.getFileLength)
+        case _ => None
+      }
+    }
+  }
+
+  protected def addFileAsZipEntry(
+      zipStream: ZipOutputStream,
+      path: Path,
+      entryName: String): Unit = {
+    Utils.tryWithResource(fileSystem.open(path, 1 * 1024 * 1024)) { inputStream =>
+      zipStream.putNextEntry(new ZipEntry(entryName))
+      ByteStreams.copy(inputStream, zipStream)
+      zipStream.closeEntry()
+    }
+  }
+
+  /** Returns the last index of event log files. None for single event log file. */
+  def lastIndex: Option[Long]
+
+  /**
+   * Returns the size of file for the last index of event log files. Returns its size for
+   * single event log file.
+   */
+  def fileSizeForLastIndex: Long
+
+  /** Returns whether the application is completed. */
+  def completed: Boolean
+
+  /**
+   * Returns the size of file for the last index (itself for single event log file) of event log
+   * files, only when underlying input stream is DFSInputStream. Otherwise returns None.
+   */
+  def fileSizeForLastIndexForDFS: Option[Long]
+
+  /**
+   * Returns the modification time for the last index (itself for single event log file)
+   * of event log files.
+   */
+  def modificationTime: Long
+
+  /**
+   * This method compresses the files passed in, and writes the compressed data out into the
+   * ZipOutputStream passed in. Each file is written as a new ZipEntry with its name being
+   * the name of the file being compressed.
+   */
+  def zipEventLogFiles(zipStream: ZipOutputStream): Unit
+
+  /** Returns all available event log files. */
+  def listEventLogFiles: Seq[FileStatus]
+
+  /** Returns the short compression name if being used. None if it's uncompressed. */
+  def compressionCodec: Option[String]
+
+  /** Returns the size of all event log files. */
+  def totalSize: Long
+}
+
+object EventLogFileReader {
+  // A cache for compression codecs to avoid creating the same codec many times
+  private val codecMap = new ConcurrentHashMap[String, CompressionCodec]()
+
+  def apply(
+      fs: FileSystem,
+      path: Path,
+      lastIndex: Option[Long]): EventLogFileReader = {
+    lastIndex match {
+      case Some(_) => new RollingEventLogFilesFileReader(fs, path)
+      case None => new SingleFileEventLogFileReader(fs, path)
+    }
+  }
+
+  def apply(fs: FileSystem, path: Path): Option[EventLogFileReader] = {
+    apply(fs, fs.getFileStatus(path))
+  }
+
+  def apply(fs: FileSystem, status: FileStatus): Option[EventLogFileReader] = {
+    if (isSingleEventLog(status)) {
+      Some(new SingleFileEventLogFileReader(fs, status.getPath))
+    } else if (isRollingEventLogs(status)) {
+      Some(new RollingEventLogFilesFileReader(fs, status.getPath))
+    } else {
+      None
+    }
+  }
+
+  /**
+   * Opens an event log file and returns an input stream that contains the event data.
+   *
+   * @return input stream that holds one JSON record per line.
+   */
+  def openEventLog(log: Path, fs: FileSystem): InputStream = {
+    val in = new BufferedInputStream(fs.open(log))
+    try {
+      val codec = codecName(log).map { c =>
+        codecMap.computeIfAbsent(c, CompressionCodec.createCodec(new SparkConf, _))
+      }
+      codec.map(_.compressedContinuousInputStream(in)).getOrElse(in)
+    } catch {
+      case e: Throwable =>
+        in.close()
+        throw e
+    }
+  }
+
+  private def isSingleEventLog(status: FileStatus): Boolean = {
+    !status.isDirectory &&
+      // FsHistoryProvider used to generate a hidden file which can't be read.  Accidentally
+      // reading a garbage file is safe, but we would log an error which can be scary to
+      // the end-user.
+      !status.getPath.getName.startsWith(".")
+  }
+
+  private def isRollingEventLogs(status: FileStatus): Boolean = {
+    RollingEventLogFilesWriter.isEventLogDir(status)
+  }
+}
+
+/**
+ * The reader which will read the information of single event log file.
+ *
+ * This reader gets the status of event log file only once when required;
+ * It may not give "live" status of file that could be changing concurrently, and
+ * FileNotFoundException could occur if the log file is renamed before getting the
+ * status of log file.
+ */
+class SingleFileEventLogFileReader(
+    fs: FileSystem,
+    path: Path) extends EventLogFileReader(fs, path) {
+  private lazy val status = fileSystem.getFileStatus(rootPath)
+
+  override def lastIndex: Option[Long] = None
+
+  override def fileSizeForLastIndex: Long = status.getLen
+
+  override def completed: Boolean = !rootPath.getName.endsWith(EventLogFileWriter.IN_PROGRESS)
+
+  override def fileSizeForLastIndexForDFS: Option[Long] = {
+    if (completed) {
+      Some(fileSizeForLastIndex)
+    } else {
+      fileSizeForDFS(rootPath)
+    }
+  }
+
+  override def modificationTime: Long = status.getModificationTime
+
+  override def zipEventLogFiles(zipStream: ZipOutputStream): Unit = {
+    addFileAsZipEntry(zipStream, rootPath, rootPath.getName)
+  }
+
+  override def listEventLogFiles: Seq[FileStatus] = Seq(status)
+
+  override def compressionCodec: Option[String] = EventLogFileWriter.codecName(rootPath)
+
+  override def totalSize: Long = fileSizeForLastIndex
+}
+
+/**
+ * The reader which will read the information of rolled multiple event log files.
+ *
+ * This reader lists the files only once; if caller would like to play with updated list,
+ * it needs to create another reader instance.
+ */
+class RollingEventLogFilesFileReader(
+    fs: FileSystem,
+    path: Path) extends EventLogFileReader(fs, path) {
+  import RollingEventLogFilesWriter._
+
+  private lazy val files: Seq[FileStatus] = {
+    val ret = fs.listStatus(rootPath).toSeq
+    require(ret.exists(isEventLogFile), "Log directory must contain at least one event log file!")
+    require(ret.exists(isAppStatusFile), "Log directory must contain an appstatus file!")
+    ret
+  }
+
+  private lazy val appStatusFile = files.find(isAppStatusFile).get
+
+  private lazy val eventLogFiles: Seq[FileStatus] = {
+    val eventLogFiles = files.filter(isEventLogFile).sortBy { status =>
+      getIndex(status.getPath.getName)
+    }
+    val indices = eventLogFiles.map { file => getIndex(file.getPath.getName) }.sorted
+    require((indices.head to indices.last) == indices, "Found missing event log file, expected" +
+      s" indices: ${(indices.head to indices.last)}, actual: ${indices}")
+    eventLogFiles
+  }
+
+  override def lastIndex: Option[Long] = Some(getIndex(lastEventLogFile.getPath.getName))
+
+  override def fileSizeForLastIndex: Long = lastEventLogFile.getLen
+
+  override def completed: Boolean = {
+    !appStatusFile.getPath.getName.endsWith(EventLogFileWriter.IN_PROGRESS)
+  }
+
+  override def fileSizeForLastIndexForDFS: Option[Long] = {
+    if (completed) {
+      Some(fileSizeForLastIndex)
+    } else {
+      fileSizeForDFS(lastEventLogFile.getPath)
+    }
+  }
+
+  override def modificationTime: Long = lastEventLogFile.getModificationTime
+
+  override def zipEventLogFiles(zipStream: ZipOutputStream): Unit = {
+    val dirEntryName = rootPath.getName + "/"
+    zipStream.putNextEntry(new ZipEntry(dirEntryName))
+    files.foreach { file =>
+      addFileAsZipEntry(zipStream, file.getPath, dirEntryName + file.getPath.getName)
+    }
+  }
+
+  override def listEventLogFiles: Seq[FileStatus] = eventLogFiles
+
+  override def compressionCodec: Option[String] = {
+    EventLogFileWriter.codecName(eventLogFiles.head.getPath)
+  }
+
+  override def totalSize: Long = eventLogFiles.map(_.getLen).sum
+
+  private def lastEventLogFile: FileStatus = eventLogFiles.last
+}