Github user tgravescs commented on a diff in the pull request: https://github.com/apache/spark/pull/204#discussion_r11256081 --- Diff: core/src/main/scala/org/apache/spark/deploy/history/HistoryServer.scala --- @@ -0,0 +1,221 @@ +/* + * 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.net.URI +import javax.servlet.http.HttpServletRequest + +import scala.collection.mutable +import scala.concurrent._ +import scala.concurrent.ExecutionContext.Implicits.global +import scala.util.{Failure, Success} + +import org.apache.hadoop.fs.{FileStatus, Path} +import org.eclipse.jetty.servlet.ServletContextHandler + +import org.apache.spark.{Logging, SecurityManager, SparkConf} +import org.apache.spark.deploy.SparkUIContainer +import org.apache.spark.ui.SparkUI +import org.apache.spark.ui.JettyUtils._ +import org.apache.spark.util.Utils +import org.apache.spark.scheduler.{ApplicationEventListener, ReplayListenerBus} + +/** + * A web server that renders SparkUIs of finished applications. + * + * For the standalone mode, MasterWebUI already achieves this functionality. Thus, the + * main use case of the HistoryServer is in other deploy modes (e.g. Yarn or Mesos). + * + * The logging directory structure is as follows: Within the given base directory, each + * application's event logs are maintained in the application's own sub-directory. This + * is the same structure as maintained in the event log write code path in + * EventLoggingListener. + * + * @param baseLogDir The base directory in which event logs are found + * @param requestedPort The requested port to which this server is to be bound + */ +class HistoryServer(val baseLogDir: String, requestedPort: Int) + extends SparkUIContainer("History Server") with Logging { + + private val fileSystem = Utils.getHadoopFileSystem(new URI(baseLogDir)) + private val host = Option(System.getenv("SPARK_PUBLIC_DNS")).getOrElse(Utils.localHostName()) + private val port = requestedPort + private val conf = new SparkConf + private val securityManager = new SecurityManager(conf) + private val indexPage = new IndexPage(this) + + // A timestamp of when the disk was last accessed to check for log updates + private var lastLogCheck = -1L + + private val handlers = Seq[ServletContextHandler]( + createStaticHandler(HistoryServer.STATIC_RESOURCE_DIR, "/static"), + createServletHandler("/", + (request: HttpServletRequest) => indexPage.render(request), securityMgr = securityManager) + ) + + val appIdToInfo = mutable.HashMap[String, ApplicationHistoryInfo]() + + /** Bind to the HTTP server behind this web interface */ + override def bind() { + try { + serverInfo = Some(startJettyServer(host, port, handlers, conf)) + logInfo("Started HistoryServer at http://%s:%d".format(host, boundPort)) + } catch { + case e: Exception => + logError("Failed to bind HistoryServer", e) + System.exit(1) + } + checkForLogs() + } + + /** + * Asynchronously check for any updates to event logs in the base directory. + * + * If a new finished application is found, the server renders the associated SparkUI + * from the application's event logs, attaches this UI to itself, and stores metadata + * information for this application. + * + * If the logs for an existing finished application are no longer found, the server + * removes all associated information and detaches the SparkUI. + */ + def checkForLogs() { + if (logCheckReady) { + lastLogCheck = System.currentTimeMillis + val asyncCheck = future { + val logStatus = fileSystem.listStatus(new Path(baseLogDir)) + val logDirs = if (logStatus != null) logStatus.filter(_.isDir).toSeq else Seq[FileStatus]() + + // Render SparkUI for any new completed applications + logDirs.foreach { dir => + val path = dir.getPath.toString + val appId = getAppId(path) + val lastUpdated = getModificationTime(dir) + if (!appIdToInfo.contains(appId)) { + maybeRenderUI(appId, path, lastUpdated) + } + } + + // Remove any outdated SparkUIs + val appIds = logDirs.map { dir => getAppId(dir.getPath.toString) } + appIdToInfo.foreach { case (appId, info) => + if (!appIds.contains(appId)) { + detachUI(info.ui) + appIdToInfo.remove(appId) + } + } + } + asyncCheck.onFailure { case t => + logError("Unable to synchronize HistoryServer with files on disk: ", t) + } + } + } + + /** + * Render a new SparkUI from the event logs if the associated application is finished. + * + * HistoryServer looks for a special file that indicates application completion in the given + * directory. If this file exists, the associated application is regarded to be complete, in + * which case the server proceeds to render the SparkUI. Otherwise, the server does nothing. + */ + private def maybeRenderUI(appId: String, logPath: String, lastUpdated: Long) { + val replayBus = new ReplayListenerBus(logPath) + replayBus.start() + + // If the application completion file is found + if (replayBus.isApplicationComplete) { + val ui = new SparkUI(replayBus, appId, "/history/%s".format(appId)) + val appListener = new ApplicationEventListener + replayBus.addListener(appListener) + + // Do not call ui.bind() to avoid creating a new server for each application + ui.start() + val success = replayBus.replay() + if (success) { + attachUI(ui) + val appName = if (appListener.applicationStarted) appListener.appName else appId + ui.setAppName("%s (finished)".format(appName)) + val startTime = appListener.startTime + val endTime = appListener.endTime + val info = ApplicationHistoryInfo(appName, startTime, endTime, lastUpdated, logPath, ui) + appIdToInfo(appId) = info + } + } else { + logWarning("Skipping incomplete application: %s".format(logPath)) + } + replayBus.stop() --- End diff -- This is probably what is causing the exception with: java.io.IOException: Filesystem closed at org.apache.hadoop.hdfs.DFSClient.checkOpen(DFSClient.java:398) In stop() it is closing the filesystem. That filesystem is cached and used throughout the process so you can't close it.
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