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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
import java.io._
import java.lang.reflect.Constructor
import java.net.{URI}
import java.util.{Arrays, Locale, Properties, ServiceLoader, UUID}
import java.util.concurrent.{ConcurrentHashMap, ConcurrentMap}
import java.util.concurrent.atomic.{AtomicBoolean, AtomicInteger, AtomicReference}
import scala.collection.JavaConverters._
import scala.collection.Map
import scala.collection.generic.Growable
import scala.collection.mutable.HashMap
import scala.language.implicitConversions
import scala.reflect.{classTag, ClassTag}
import scala.util.control.NonFatal
import com.google.common.collect.MapMaker
import org.apache.commons.lang3.SerializationUtils
import org.apache.hadoop.conf.Configuration
import org.apache.hadoop.fs.{FileSystem, Path}
import org.apache.hadoop.io.{ArrayWritable, BooleanWritable, BytesWritable, DoubleWritable, FloatWritable, IntWritable, LongWritable, NullWritable, Text, Writable}
import org.apache.hadoop.mapred.{FileInputFormat, InputFormat, JobConf, SequenceFileInputFormat, TextInputFormat}
import org.apache.hadoop.mapreduce.{InputFormat => NewInputFormat, Job => NewHadoopJob}
import org.apache.hadoop.mapreduce.lib.input.{FileInputFormat => NewFileInputFormat}
import org.apache.spark.annotation.DeveloperApi
import org.apache.spark.broadcast.Broadcast
import org.apache.spark.deploy.{LocalSparkCluster, SparkHadoopUtil}
import org.apache.spark.input.{FixedLengthBinaryInputFormat, PortableDataStream, StreamInputFormat, WholeTextFileInputFormat}
import org.apache.spark.internal.Logging
import org.apache.spark.internal.config._
import org.apache.spark.io.CompressionCodec
import org.apache.spark.partial.{ApproximateEvaluator, PartialResult}
import org.apache.spark.rdd._
import org.apache.spark.rpc.RpcEndpointRef
import org.apache.spark.scheduler._
import org.apache.spark.scheduler.cluster.{CoarseGrainedSchedulerBackend, StandaloneSchedulerBackend}
import org.apache.spark.scheduler.local.LocalSchedulerBackend
import org.apache.spark.storage._
import org.apache.spark.storage.BlockManagerMessages.TriggerThreadDump
import org.apache.spark.ui.{ConsoleProgressBar, SparkUI}
import org.apache.spark.ui.jobs.JobProgressListener
import org.apache.spark.util._
/**
* Main entry point for Spark functionality. A SparkContext represents the connection to a Spark
* cluster, and can be used to create RDDs, accumulators and broadcast variables on that cluster.
*
* Only one SparkContext may be active per JVM. You must `stop()` the active SparkContext before
* creating a new one. This limitation may eventually be removed; see SPARK-2243 for more details.
*
* @param config a Spark Config object describing the application configuration. Any settings in
* this config overrides the default configs as well as system properties.
*/
class SparkContext(config: SparkConf) extends Logging {
// The call site where this SparkContext was constructed.
private val creationSite: CallSite = Utils.getCallSite()
// If true, log warnings instead of throwing exceptions when multiple SparkContexts are active
private val allowMultipleContexts: Boolean =
config.getBoolean("spark.driver.allowMultipleContexts", false)
// In order to prevent multiple SparkContexts from being active at the same time, mark this
// context as having started construction.
// NOTE: this must be placed at the beginning of the SparkContext constructor.
SparkContext.markPartiallyConstructed(this, allowMultipleContexts)
val startTime = System.currentTimeMillis()
private[spark] val stopped: AtomicBoolean = new AtomicBoolean(false)
private[spark] def assertNotStopped(): Unit = {
if (stopped.get()) {
val activeContext = SparkContext.activeContext.get()
val activeCreationSite =
if (activeContext == null) {
"(No active SparkContext.)"
} else {
activeContext.creationSite.longForm
}
throw new IllegalStateException(
s"""Cannot call methods on a stopped SparkContext.
|This stopped SparkContext was created at:
|
|${creationSite.longForm}
|
|The currently active SparkContext was created at:
|
|$activeCreationSite
""".stripMargin)
}
}
/**
* Create a SparkContext that loads settings from system properties (for instance, when
* launching with ./bin/spark-submit).
*/
def this() = this(new SparkConf())
/**
* Alternative constructor that allows setting common Spark properties directly
*
* @param master Cluster URL to connect to (e.g. mesos://host:port, spark://host:port, local[4]).
* @param appName A name for your application, to display on the cluster web UI
* @param conf a [[org.apache.spark.SparkConf]] object specifying other Spark parameters
*/
def this(master: String, appName: String, conf: SparkConf) =
this(SparkContext.updatedConf(conf, master, appName))
/**
* Alternative constructor that allows setting common Spark properties directly
*
* @param master Cluster URL to connect to (e.g. mesos://host:port, spark://host:port, local[4]).
* @param appName A name for your application, to display on the cluster web UI.
* @param sparkHome Location where Spark is installed on cluster nodes.
* @param jars Collection of JARs to send to the cluster. These can be paths on the local file
* system or HDFS, HTTP, HTTPS, or FTP URLs.
* @param environment Environment variables to set on worker nodes.
*/
def this(
master: String,
appName: String,
sparkHome: String = null,
jars: Seq[String] = Nil,
environment: Map[String, String] = Map()) = {
this(SparkContext.updatedConf(new SparkConf(), master, appName, sparkHome, jars, environment))
}
// NOTE: The below constructors could be consolidated using default arguments. Due to
// Scala bug SI-8479, however, this causes the compile step to fail when generating docs.
// Until we have a good workaround for that bug the constructors remain broken out.
/**
* Alternative constructor that allows setting common Spark properties directly
*
* @param master Cluster URL to connect to (e.g. mesos://host:port, spark://host:port, local[4]).
* @param appName A name for your application, to display on the cluster web UI.
*/
private[spark] def this(master: String, appName: String) =
this(master, appName, null, Nil, Map())
/**
* Alternative constructor that allows setting common Spark properties directly
*
* @param master Cluster URL to connect to (e.g. mesos://host:port, spark://host:port, local[4]).
* @param appName A name for your application, to display on the cluster web UI.
* @param sparkHome Location where Spark is installed on cluster nodes.
*/
private[spark] def this(master: String, appName: String, sparkHome: String) =
this(master, appName, sparkHome, Nil, Map())
/**
* Alternative constructor that allows setting common Spark properties directly
*
* @param master Cluster URL to connect to (e.g. mesos://host:port, spark://host:port, local[4]).
* @param appName A name for your application, to display on the cluster web UI.
* @param sparkHome Location where Spark is installed on cluster nodes.
* @param jars Collection of JARs to send to the cluster. These can be paths on the local file
* system or HDFS, HTTP, HTTPS, or FTP URLs.
*/
private[spark] def this(master: String, appName: String, sparkHome: String, jars: Seq[String]) =
this(master, appName, sparkHome, jars, Map())
// log out Spark Version in Spark driver log
logInfo(s"Running Spark version $SPARK_VERSION")
warnDeprecatedVersions()
/* ------------------------------------------------------------------------------------- *
| Private variables. These variables keep the internal state of the context, and are |
| not accessible by the outside world. They're mutable since we want to initialize all |
| of them to some neutral value ahead of time, so that calling "stop()" while the |
| constructor is still running is safe. |
* ------------------------------------------------------------------------------------- */
private var _conf: SparkConf = _
private var _eventLogDir: Option[URI] = None
private var _eventLogCodec: Option[String] = None
private var _env: SparkEnv = _
private var _jobProgressListener: JobProgressListener = _
private var _statusTracker: SparkStatusTracker = _
private var _progressBar: Option[ConsoleProgressBar] = None
private var _ui: Option[SparkUI] = None
private var _hadoopConfiguration: Configuration = _
private var _executorMemory: Int = _
private var _schedulerBackend: SchedulerBackend = _
private var _taskScheduler: TaskScheduler = _
private var _heartbeatReceiver: RpcEndpointRef = _
@volatile private var _dagScheduler: DAGScheduler = _
private var _applicationId: String = _
private var _applicationAttemptId: Option[String] = None
private var _eventLogger: Option[EventLoggingListener] = None
private var _executorAllocationManager: Option[ExecutorAllocationManager] = None
private var _cleaner: Option[ContextCleaner] = None
private var _listenerBusStarted: Boolean = false
private var _jars: Seq[String] = _
private var _files: Seq[String] = _
private var _shutdownHookRef: AnyRef = _
/* ------------------------------------------------------------------------------------- *
| Accessors and public fields. These provide access to the internal state of the |
| context. |
* ------------------------------------------------------------------------------------- */
private[spark] def conf: SparkConf = _conf
/**
* Return a copy of this SparkContext's configuration. The configuration ''cannot'' be
* changed at runtime.
*/
def getConf: SparkConf = conf.clone()
def jars: Seq[String] = _jars
def files: Seq[String] = _files
def master: String = _conf.get("spark.master")
def deployMode: String = _conf.getOption("spark.submit.deployMode").getOrElse("client")
def appName: String = _conf.get("spark.app.name")
private[spark] def isEventLogEnabled: Boolean = _conf.getBoolean("spark.eventLog.enabled", false)
private[spark] def eventLogDir: Option[URI] = _eventLogDir
private[spark] def eventLogCodec: Option[String] = _eventLogCodec
def isLocal: Boolean = Utils.isLocalMaster(_conf)
/**
* @return true if context is stopped or in the midst of stopping.
*/
def isStopped: Boolean = stopped.get()
// An asynchronous listener bus for Spark events
private[spark] val listenerBus = new LiveListenerBus(this)
// This function allows components created by SparkEnv to be mocked in unit tests:
private[spark] def createSparkEnv(
conf: SparkConf,
isLocal: Boolean,
listenerBus: LiveListenerBus): SparkEnv = {
SparkEnv.createDriverEnv(conf, isLocal, listenerBus, SparkContext.numDriverCores(master))
}
private[spark] def env: SparkEnv = _env
// Used to store a URL for each static file/jar together with the file's local timestamp
private[spark] val addedFiles = new ConcurrentHashMap[String, Long]().asScala
private[spark] val addedJars = new ConcurrentHashMap[String, Long]().asScala
// Keeps track of all persisted RDDs
private[spark] val persistentRdds = {
val map: ConcurrentMap[Int, RDD[_]] = new MapMaker().weakValues().makeMap[Int, RDD[_]]()
map.asScala
}
private[spark] def jobProgressListener: JobProgressListener = _jobProgressListener
def statusTracker: SparkStatusTracker = _statusTracker
private[spark] def progressBar: Option[ConsoleProgressBar] = _progressBar
private[spark] def ui: Option[SparkUI] = _ui
def uiWebUrl: Option[String] = _ui.map(_.webUrl)
/**
* A default Hadoop Configuration for the Hadoop code (e.g. file systems) that we reuse.
*
* @note As it will be reused in all Hadoop RDDs, it's better not to modify it unless you
* plan to set some global configurations for all Hadoop RDDs.
*/
def hadoopConfiguration: Configuration = _hadoopConfiguration
private[spark] def executorMemory: Int = _executorMemory
// Environment variables to pass to our executors.
private[spark] val executorEnvs = HashMap[String, String]()
// Set SPARK_USER for user who is running SparkContext.
val sparkUser = Utils.getCurrentUserName()
private[spark] def schedulerBackend: SchedulerBackend = _schedulerBackend
private[spark] def taskScheduler: TaskScheduler = _taskScheduler
private[spark] def taskScheduler_=(ts: TaskScheduler): Unit = {
_taskScheduler = ts
}
private[spark] def dagScheduler: DAGScheduler = _dagScheduler
private[spark] def dagScheduler_=(ds: DAGScheduler): Unit = {
_dagScheduler = ds
}
/**
* A unique identifier for the Spark application.
* Its format depends on the scheduler implementation.
* (i.e.
* in case of local spark app something like 'local-1433865536131'
* in case of YARN something like 'application_1433865536131_34483'
* )
*/
def applicationId: String = _applicationId
def applicationAttemptId: Option[String] = _applicationAttemptId
private[spark] def eventLogger: Option[EventLoggingListener] = _eventLogger
private[spark] def executorAllocationManager: Option[ExecutorAllocationManager] =
_executorAllocationManager
private[spark] def cleaner: Option[ContextCleaner] = _cleaner
private[spark] var checkpointDir: Option[String] = None
// Thread Local variable that can be used by users to pass information down the stack
protected[spark] val localProperties = new InheritableThreadLocal[Properties] {
override protected def childValue(parent: Properties): Properties = {
// Note: make a clone such that changes in the parent properties aren't reflected in
// the those of the children threads, which has confusing semantics (SPARK-10563).
SerializationUtils.clone(parent)
}
override protected def initialValue(): Properties = new Properties()
}
/* ------------------------------------------------------------------------------------- *
| Initialization. This code initializes the context in a manner that is exception-safe. |
| All internal fields holding state are initialized here, and any error prompts the |
| stop() method to be called. |
* ------------------------------------------------------------------------------------- */
private def warnSparkMem(value: String): String = {
logWarning("Using SPARK_MEM to set amount of memory to use per executor process is " +
"deprecated, please use spark.executor.memory instead.")
value
}
private def warnDeprecatedVersions(): Unit = {
val javaVersion = System.getProperty("java.version").split("[+.\\-]+", 3)
if (javaVersion.length >= 2 && javaVersion(1).toInt == 7) {
logWarning("Support for Java 7 is deprecated as of Spark 2.0.0")
}
if (scala.util.Properties.releaseVersion.exists(_.startsWith("2.10"))) {
logWarning("Support for Scala 2.10 is deprecated as of Spark 2.1.0")
}
}
/** Control our logLevel. This overrides any user-defined log settings.
* @param logLevel The desired log level as a string.
* Valid log levels include: ALL, DEBUG, ERROR, FATAL, INFO, OFF, TRACE, WARN
*/
def setLogLevel(logLevel: String) {
// let's allow lowercase or mixed case too
val upperCased = logLevel.toUpperCase(Locale.ENGLISH)
require(SparkContext.VALID_LOG_LEVELS.contains(upperCased),
s"Supplied level $logLevel did not match one of:" +
s" ${SparkContext.VALID_LOG_LEVELS.mkString(",")}")
Utils.setLogLevel(org.apache.log4j.Level.toLevel(upperCased))
}
try {
_conf = config.clone()
_conf.validateSettings()
if (!_conf.contains("spark.master")) {
throw new SparkException("A master URL must be set in your configuration")
}
if (!_conf.contains("spark.app.name")) {
throw new SparkException("An application name must be set in your configuration")
}
// System property spark.yarn.app.id must be set if user code ran by AM on a YARN cluster
if (master == "yarn" && deployMode == "cluster" && !_conf.contains("spark.yarn.app.id")) {
throw new SparkException("Detected yarn cluster mode, but isn't running on a cluster. " +
"Deployment to YARN is not supported directly by SparkContext. Please use spark-submit.")
}
if (_conf.getBoolean("spark.logConf", false)) {
logInfo("Spark configuration:\n" + _conf.toDebugString)
}
// Set Spark driver host and port system properties. This explicitly sets the configuration
// instead of relying on the default value of the config constant.
_conf.set(DRIVER_HOST_ADDRESS, _conf.get(DRIVER_HOST_ADDRESS))
_conf.setIfMissing("spark.driver.port", "0")
_conf.set("spark.executor.id", SparkContext.DRIVER_IDENTIFIER)
_jars = Utils.getUserJars(_conf)
_files = _conf.getOption("spark.files").map(_.split(",")).map(_.filter(_.nonEmpty))
.toSeq.flatten
_eventLogDir =
if (isEventLogEnabled) {
val unresolvedDir = conf.get("spark.eventLog.dir", EventLoggingListener.DEFAULT_LOG_DIR)
.stripSuffix("/")
Some(Utils.resolveURI(unresolvedDir))
} else {
None
}
_eventLogCodec = {
val compress = _conf.getBoolean("spark.eventLog.compress", false)
if (compress && isEventLogEnabled) {
Some(CompressionCodec.getCodecName(_conf)).map(CompressionCodec.getShortName)
} else {
None
}
}
if (master == "yarn" && deployMode == "client") System.setProperty("SPARK_YARN_MODE", "true")
// "_jobProgressListener" should be set up before creating SparkEnv because when creating
// "SparkEnv", some messages will be posted to "listenerBus" and we should not miss them.
_jobProgressListener = new JobProgressListener(_conf)
listenerBus.addListener(jobProgressListener)
// Create the Spark execution environment (cache, map output tracker, etc)
_env = createSparkEnv(_conf, isLocal, listenerBus)
SparkEnv.set(_env)
// If running the REPL, register the repl's output dir with the file server.
_conf.getOption("spark.repl.class.outputDir").foreach { path =>
val replUri = _env.rpcEnv.fileServer.addDirectory("/classes", new File(path))
_conf.set("spark.repl.class.uri", replUri)
}
_statusTracker = new SparkStatusTracker(this)
_progressBar =
if (_conf.getBoolean("spark.ui.showConsoleProgress", true) && !log.isInfoEnabled) {
Some(new ConsoleProgressBar(this))
} else {
None
}
_ui =
if (conf.getBoolean("spark.ui.enabled", true)) {
Some(SparkUI.createLiveUI(this, _conf, listenerBus, _jobProgressListener,
_env.securityManager, appName, startTime = startTime))
} else {
// For tests, do not enable the UI
None
}
// Bind the UI before starting the task scheduler to communicate
// the bound port to the cluster manager properly
_ui.foreach(_.bind())
_hadoopConfiguration = SparkHadoopUtil.get.newConfiguration(_conf)
// Add each JAR given through the constructor
if (jars != null) {
jars.foreach(addJar)
}
if (files != null) {
files.foreach(addFile)
}
_executorMemory = _conf.getOption("spark.executor.memory")
.orElse(Option(System.getenv("SPARK_EXECUTOR_MEMORY")))
.orElse(Option(System.getenv("SPARK_MEM"))
.map(warnSparkMem))
.map(Utils.memoryStringToMb)
.getOrElse(1024)
// Convert java options to env vars as a work around
// since we can't set env vars directly in sbt.
for { (envKey, propKey) <- Seq(("SPARK_TESTING", "spark.testing"))
value <- Option(System.getenv(envKey)).orElse(Option(System.getProperty(propKey)))} {
executorEnvs(envKey) = value
}
Option(System.getenv("SPARK_PREPEND_CLASSES")).foreach { v =>
executorEnvs("SPARK_PREPEND_CLASSES") = v
}
// The Mesos scheduler backend relies on this environment variable to set executor memory.
// TODO: Set this only in the Mesos scheduler.
executorEnvs("SPARK_EXECUTOR_MEMORY") = executorMemory + "m"
executorEnvs ++= _conf.getExecutorEnv
executorEnvs("SPARK_USER") = sparkUser
// We need to register "HeartbeatReceiver" before "createTaskScheduler" because Executor will
// retrieve "HeartbeatReceiver" in the constructor. (SPARK-6640)
_heartbeatReceiver = env.rpcEnv.setupEndpoint(
HeartbeatReceiver.ENDPOINT_NAME, new HeartbeatReceiver(this))
// Create and start the scheduler
val (sched, ts) = SparkContext.createTaskScheduler(this, master, deployMode)
_schedulerBackend = sched
_taskScheduler = ts
_dagScheduler = new DAGScheduler(this)
_heartbeatReceiver.ask[Boolean](TaskSchedulerIsSet)
// start TaskScheduler after taskScheduler sets DAGScheduler reference in DAGScheduler's
// constructor
_taskScheduler.start()
_applicationId = _taskScheduler.applicationId()
_applicationAttemptId = taskScheduler.applicationAttemptId()
_conf.set("spark.app.id", _applicationId)
if (_conf.getBoolean("spark.ui.reverseProxy", false)) {
System.setProperty("spark.ui.proxyBase", "/proxy/" + _applicationId)
}
_ui.foreach(_.setAppId(_applicationId))
_env.blockManager.initialize(_applicationId)
// The metrics system for Driver need to be set spark.app.id to app ID.
// So it should start after we get app ID from the task scheduler and set spark.app.id.
_env.metricsSystem.start()
// Attach the driver metrics servlet handler to the web ui after the metrics system is started.
_env.metricsSystem.getServletHandlers.foreach(handler => ui.foreach(_.attachHandler(handler)))
_eventLogger =
if (isEventLogEnabled) {
val logger =
new EventLoggingListener(_applicationId, _applicationAttemptId, _eventLogDir.get,
_conf, _hadoopConfiguration)
logger.start()
listenerBus.addListener(logger)
Some(logger)
} else {
None
}
// Optionally scale number of executors dynamically based on workload. Exposed for testing.
val dynamicAllocationEnabled = Utils.isDynamicAllocationEnabled(_conf)
_executorAllocationManager =
if (dynamicAllocationEnabled) {
schedulerBackend match {
case b: ExecutorAllocationClient =>
Some(new ExecutorAllocationManager(
schedulerBackend.asInstanceOf[ExecutorAllocationClient], listenerBus, _conf))
case _ =>
None
}
} else {
None
}
_executorAllocationManager.foreach(_.start())
_cleaner =
if (_conf.getBoolean("spark.cleaner.referenceTracking", true)) {
Some(new ContextCleaner(this))
} else {
None
}
_cleaner.foreach(_.start())
setupAndStartListenerBus()
postEnvironmentUpdate()
postApplicationStart()
// Post init
_taskScheduler.postStartHook()
_env.metricsSystem.registerSource(_dagScheduler.metricsSource)
_env.metricsSystem.registerSource(new BlockManagerSource(_env.blockManager))
_executorAllocationManager.foreach { e =>
_env.metricsSystem.registerSource(e.executorAllocationManagerSource)
}
// Make sure the context is stopped if the user forgets about it. This avoids leaving
// unfinished event logs around after the JVM exits cleanly. It doesn't help if the JVM
// is killed, though.
logDebug("Adding shutdown hook") // force eager creation of logger
_shutdownHookRef = ShutdownHookManager.addShutdownHook(
ShutdownHookManager.SPARK_CONTEXT_SHUTDOWN_PRIORITY) { () =>
logInfo("Invoking stop() from shutdown hook")
stop()
}
} catch {
case NonFatal(e) =>
logError("Error initializing SparkContext.", e)
try {
stop()
} catch {
case NonFatal(inner) =>
logError("Error stopping SparkContext after init error.", inner)
} finally {
throw e
}
}
/**
* Called by the web UI to obtain executor thread dumps. This method may be expensive.
* Logs an error and returns None if we failed to obtain a thread dump, which could occur due
* to an executor being dead or unresponsive or due to network issues while sending the thread
* dump message back to the driver.
*/
private[spark] def getExecutorThreadDump(executorId: String): Option[Array[ThreadStackTrace]] = {
try {
if (executorId == SparkContext.DRIVER_IDENTIFIER) {
Some(Utils.getThreadDump())
} else {
val endpointRef = env.blockManager.master.getExecutorEndpointRef(executorId).get
Some(endpointRef.askWithRetry[Array[ThreadStackTrace]](TriggerThreadDump))
}
} catch {
case e: Exception =>
logError(s"Exception getting thread dump from executor $executorId", e)
None
}
}
private[spark] def getLocalProperties: Properties = localProperties.get()
private[spark] def setLocalProperties(props: Properties) {
localProperties.set(props)
}
/**
* Set a local property that affects jobs submitted from this thread, such as the Spark fair
* scheduler pool. User-defined properties may also be set here. These properties are propagated
* through to worker tasks and can be accessed there via
* [[org.apache.spark.TaskContext#getLocalProperty]].
*
* These properties are inherited by child threads spawned from this thread. This
* may have unexpected consequences when working with thread pools. The standard java
* implementation of thread pools have worker threads spawn other worker threads.
* As a result, local properties may propagate unpredictably.
*/
def setLocalProperty(key: String, value: String) {
if (value == null) {
localProperties.get.remove(key)
} else {
localProperties.get.setProperty(key, value)
}
}
/**
* Get a local property set in this thread, or null if it is missing. See
* `org.apache.spark.SparkContext.setLocalProperty`.
*/
def getLocalProperty(key: String): String =
Option(localProperties.get).map(_.getProperty(key)).orNull
/** Set a human readable description of the current job. */
def setJobDescription(value: String) {
setLocalProperty(SparkContext.SPARK_JOB_DESCRIPTION, value)
}
/**
* Assigns a group ID to all the jobs started by this thread until the group ID is set to a
* different value or cleared.
*
* Often, a unit of execution in an application consists of multiple Spark actions or jobs.
* Application programmers can use this method to group all those jobs together and give a
* group description. Once set, the Spark web UI will associate such jobs with this group.
*
* The application can also use `org.apache.spark.SparkContext.cancelJobGroup` to cancel all
* running jobs in this group. For example,
* {{{
* // In the main thread:
* sc.setJobGroup("some_job_to_cancel", "some job description")
* sc.parallelize(1 to 10000, 2).map { i => Thread.sleep(10); i }.count()
*
* // In a separate thread:
* sc.cancelJobGroup("some_job_to_cancel")
* }}}
*
* If interruptOnCancel is set to true for the job group, then job cancellation will result
* in Thread.interrupt() being called on the job's executor threads. This is useful to help ensure
* that the tasks are actually stopped in a timely manner, but is off by default due to HDFS-1208,
* where HDFS may respond to Thread.interrupt() by marking nodes as dead.
*/
def setJobGroup(groupId: String, description: String, interruptOnCancel: Boolean = false) {
setLocalProperty(SparkContext.SPARK_JOB_DESCRIPTION, description)
setLocalProperty(SparkContext.SPARK_JOB_GROUP_ID, groupId)
// Note: Specifying interruptOnCancel in setJobGroup (rather than cancelJobGroup) avoids
// changing several public APIs and allows Spark cancellations outside of the cancelJobGroup
// APIs to also take advantage of this property (e.g., internal job failures or canceling from
// JobProgressTab UI) on a per-job basis.
setLocalProperty(SparkContext.SPARK_JOB_INTERRUPT_ON_CANCEL, interruptOnCancel.toString)
}
/** Clear the current thread's job group ID and its description. */
def clearJobGroup() {
setLocalProperty(SparkContext.SPARK_JOB_DESCRIPTION, null)
setLocalProperty(SparkContext.SPARK_JOB_GROUP_ID, null)
setLocalProperty(SparkContext.SPARK_JOB_INTERRUPT_ON_CANCEL, null)
}
/**
* Execute a block of code in a scope such that all new RDDs created in this body will
* be part of the same scope. For more detail, see {{org.apache.spark.rdd.RDDOperationScope}}.
*
* @note Return statements are NOT allowed in the given body.
*/
private[spark] def withScope[U](body: => U): U = RDDOperationScope.withScope[U](this)(body)
// Methods for creating RDDs
/** Distribute a local Scala collection to form an RDD.
*
* @note Parallelize acts lazily. If `seq` is a mutable collection and is altered after the call
* to parallelize and before the first action on the RDD, the resultant RDD will reflect the
* modified collection. Pass a copy of the argument to avoid this.
* @note avoid using `parallelize(Seq())` to create an empty `RDD`. Consider `emptyRDD` for an
* RDD with no partitions, or `parallelize(Seq[T]())` for an RDD of `T` with empty partitions.
*/
def parallelize[T: ClassTag](
seq: Seq[T],
numSlices: Int = defaultParallelism): RDD[T] = withScope {
assertNotStopped()
new ParallelCollectionRDD[T](this, seq, numSlices, Map[Int, Seq[String]]())
}
/**
* Creates a new RDD[Long] containing elements from `start` to `end`(exclusive), increased by
* `step` every element.
*
* @note if we need to cache this RDD, we should make sure each partition does not exceed limit.
*
* @param start the start value.
* @param end the end value.
* @param step the incremental step
* @param numSlices the partition number of the new RDD.
* @return
*/
def range(
start: Long,
end: Long,
step: Long = 1,
numSlices: Int = defaultParallelism): RDD[Long] = withScope {
assertNotStopped()
// when step is 0, range will run infinitely
require(step != 0, "step cannot be 0")
val numElements: BigInt = {
val safeStart = BigInt(start)
val safeEnd = BigInt(end)
if ((safeEnd - safeStart) % step == 0 || (safeEnd > safeStart) != (step > 0)) {
(safeEnd - safeStart) / step
} else {
// the remainder has the same sign with range, could add 1 more
(safeEnd - safeStart) / step + 1
}
}
parallelize(0 until numSlices, numSlices).mapPartitionsWithIndex { (i, _) =>
val partitionStart = (i * numElements) / numSlices * step + start
val partitionEnd = (((i + 1) * numElements) / numSlices) * step + start
def getSafeMargin(bi: BigInt): Long =
if (bi.isValidLong) {
bi.toLong
} else if (bi > 0) {
Long.MaxValue
} else {
Long.MinValue
}
val safePartitionStart = getSafeMargin(partitionStart)
val safePartitionEnd = getSafeMargin(partitionEnd)
new Iterator[Long] {
private[this] var number: Long = safePartitionStart
private[this] var overflow: Boolean = false
override def hasNext =
if (!overflow) {
if (step > 0) {
number < safePartitionEnd
} else {
number > safePartitionEnd
}
} else false
override def next() = {
val ret = number
number += step
if (number < ret ^ step < 0) {
// we have Long.MaxValue + Long.MaxValue < Long.MaxValue
// and Long.MinValue + Long.MinValue > Long.MinValue, so iff the step causes a step
// back, we are pretty sure that we have an overflow.
overflow = true
}
ret
}
}
}
}
/** Distribute a local Scala collection to form an RDD.
*
* This method is identical to `parallelize`.
*/
def makeRDD[T: ClassTag](
seq: Seq[T],
numSlices: Int = defaultParallelism): RDD[T] = withScope {
parallelize(seq, numSlices)
}
/**
* Distribute a local Scala collection to form an RDD, with one or more
* location preferences (hostnames of Spark nodes) for each object.
* Create a new partition for each collection item.
*/
def makeRDD[T: ClassTag](seq: Seq[(T, Seq[String])]): RDD[T] = withScope {
assertNotStopped()
val indexToPrefs = seq.zipWithIndex.map(t => (t._2, t._1._2)).toMap
new ParallelCollectionRDD[T](this, seq.map(_._1), math.max(seq.size, 1), indexToPrefs)
}
/**
* Read a text file from HDFS, a local file system (available on all nodes), or any
* Hadoop-supported file system URI, and return it as an RDD of Strings.
*/
def textFile(
path: String,
minPartitions: Int = defaultMinPartitions): RDD[String] = withScope {
assertNotStopped()
hadoopFile(path, classOf[TextInputFormat], classOf[LongWritable], classOf[Text],
minPartitions).map(pair => pair._2.toString).setName(path)
}
/**
* Read a directory of text files from HDFS, a local file system (available on all nodes), or any
* Hadoop-supported file system URI. Each file is read as a single record and returned in a
* key-value pair, where the key is the path of each file, the value is the content of each file.
*
* <p> For example, if you have the following files:
* {{{
* hdfs://a-hdfs-path/part-00000
* hdfs://a-hdfs-path/part-00001
* ...
* hdfs://a-hdfs-path/part-nnnnn
* }}}
*
* Do `val rdd = sparkContext.wholeTextFile("hdfs://a-hdfs-path")`,
*
* <p> then `rdd` contains
* {{{
* (a-hdfs-path/part-00000, its content)
* (a-hdfs-path/part-00001, its content)
* ...
* (a-hdfs-path/part-nnnnn, its content)
* }}}
*
* @note Small files are preferred, large file is also allowable, but may cause bad performance.
* @note On some filesystems, `.../path/&#42;` can be a more efficient way to read all files
* in a directory rather than `.../path/` or `.../path`
*
* @param path Directory to the input data files, the path can be comma separated paths as the
* list of inputs.
* @param minPartitions A suggestion value of the minimal splitting number for input data.
*/
def wholeTextFiles(
path: String,
minPartitions: Int = defaultMinPartitions): RDD[(String, String)] = withScope {
assertNotStopped()
val job = NewHadoopJob.getInstance(hadoopConfiguration)
// Use setInputPaths so that wholeTextFiles aligns with hadoopFile/textFile in taking
// comma separated files as input. (see SPARK-7155)
NewFileInputFormat.setInputPaths(job, path)
val updateConf = job.getConfiguration
new WholeTextFileRDD(
this,
classOf[WholeTextFileInputFormat],
classOf[Text],
classOf[Text],
updateConf,
minPartitions).map(record => (record._1.toString, record._2.toString)).setName(path)
}
/**
* Get an RDD for a Hadoop-readable dataset as PortableDataStream for each file
* (useful for binary data)
*
* For example, if you have the following files:
* {{{
* hdfs://a-hdfs-path/part-00000
* hdfs://a-hdfs-path/part-00001
* ...
* hdfs://a-hdfs-path/part-nnnnn
* }}}
*
* Do
* `val rdd = sparkContext.binaryFiles("hdfs://a-hdfs-path")`,
*
* then `rdd` contains
* {{{
* (a-hdfs-path/part-00000, its content)
* (a-hdfs-path/part-00001, its content)
* ...
* (a-hdfs-path/part-nnnnn, its content)
* }}}
*
* @note Small files are preferred; very large files may cause bad performance.
* @note On some filesystems, `.../path/&#42;` can be a more efficient way to read all files
* in a directory rather than `.../path/` or `.../path`
*
* @param path Directory to the input data files, the path can be comma separated paths as the
* list of inputs.
* @param minPartitions A suggestion value of the minimal splitting number for input data.
*/
def binaryFiles(
path: String,
minPartitions: Int = defaultMinPartitions): RDD[(String, PortableDataStream)] = withScope {
assertNotStopped()
val job = NewHadoopJob.getInstance(hadoopConfiguration)
// Use setInputPaths so that binaryFiles aligns with hadoopFile/textFile in taking
// comma separated files as input. (see SPARK-7155)
NewFileInputFormat.setInputPaths(job, path)
val updateConf = job.getConfiguration
new BinaryFileRDD(
this,
classOf[StreamInputFormat],
classOf[String],
classOf[PortableDataStream],
updateConf,
minPartitions).setName(path)
}
/**
* Load data from a flat binary file, assuming the length of each record is constant.
*
* @note We ensure that the byte array for each record in the resulting RDD
* has the provided record length.
*
* @param path Directory to the input data files, the path can be comma separated paths as the
* list of inputs.
* @param recordLength The length at which to split the records
* @param conf Configuration for setting up the dataset.
*
* @return An RDD of data with values, represented as byte arrays
*/
def binaryRecords(
path: String,
recordLength: Int,
conf: Configuration = hadoopConfiguration): RDD[Array[Byte]] = withScope {
assertNotStopped()
conf.setInt(FixedLengthBinaryInputFormat.RECORD_LENGTH_PROPERTY, recordLength)
val br = newAPIHadoopFile[LongWritable, BytesWritable, FixedLengthBinaryInputFormat](path,
classOf[FixedLengthBinaryInputFormat],
classOf[LongWritable],
classOf[BytesWritable],
conf = conf)
br.map { case (k, v) =>
val bytes = v.copyBytes()
assert(bytes.length == recordLength, "Byte array does not have correct length")
bytes
}
}
/**
* Get an RDD for a Hadoop-readable dataset from a Hadoop JobConf given its InputFormat and other
* necessary info (e.g. file name for a filesystem-based dataset, table name for HyperTable),
* using the older MapReduce API (`org.apache.hadoop.mapred`).
*
* @param conf JobConf for setting up the dataset. Note: This will be put into a Broadcast.
* Therefore if you plan to reuse this conf to create multiple RDDs, you need to make
* sure you won't modify the conf. A safe approach is always creating a new conf for
* a new RDD.
* @param inputFormatClass Class of the InputFormat
* @param keyClass Class of the keys
* @param valueClass Class of the values
* @param minPartitions Minimum number of Hadoop Splits to generate.
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def hadoopRDD[K, V](
conf: JobConf,
inputFormatClass: Class[_ <: InputFormat[K, V]],
keyClass: Class[K],
valueClass: Class[V],
minPartitions: Int = defaultMinPartitions): RDD[(K, V)] = withScope {
assertNotStopped()
// This is a hack to enforce loading hdfs-site.xml.
// See SPARK-11227 for details.
FileSystem.getLocal(conf)
// Add necessary security credentials to the JobConf before broadcasting it.
SparkHadoopUtil.get.addCredentials(conf)
new HadoopRDD(this, conf, inputFormatClass, keyClass, valueClass, minPartitions)
}
/** Get an RDD for a Hadoop file with an arbitrary InputFormat
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def hadoopFile[K, V](
path: String,
inputFormatClass: Class[_ <: InputFormat[K, V]],
keyClass: Class[K],
valueClass: Class[V],
minPartitions: Int = defaultMinPartitions): RDD[(K, V)] = withScope {
assertNotStopped()
// This is a hack to enforce loading hdfs-site.xml.
// See SPARK-11227 for details.
FileSystem.getLocal(hadoopConfiguration)
// A Hadoop configuration can be about 10 KB, which is pretty big, so broadcast it.
val confBroadcast = broadcast(new SerializableConfiguration(hadoopConfiguration))
val setInputPathsFunc = (jobConf: JobConf) => FileInputFormat.setInputPaths(jobConf, path)
new HadoopRDD(
this,
confBroadcast,
Some(setInputPathsFunc),
inputFormatClass,
keyClass,
valueClass,
minPartitions).setName(path)
}
/**
* Smarter version of hadoopFile() that uses class tags to figure out the classes of keys,
* values and the InputFormat so that users don't need to pass them directly. Instead, callers
* can just write, for example,
* {{{
* val file = sparkContext.hadoopFile[LongWritable, Text, TextInputFormat](path, minPartitions)
* }}}
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def hadoopFile[K, V, F <: InputFormat[K, V]]
(path: String, minPartitions: Int)
(implicit km: ClassTag[K], vm: ClassTag[V], fm: ClassTag[F]): RDD[(K, V)] = withScope {
hadoopFile(path,
fm.runtimeClass.asInstanceOf[Class[F]],
km.runtimeClass.asInstanceOf[Class[K]],
vm.runtimeClass.asInstanceOf[Class[V]],
minPartitions)
}
/**
* Smarter version of hadoopFile() that uses class tags to figure out the classes of keys,
* values and the InputFormat so that users don't need to pass them directly. Instead, callers
* can just write, for example,
* {{{
* val file = sparkContext.hadoopFile[LongWritable, Text, TextInputFormat](path)
* }}}
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def hadoopFile[K, V, F <: InputFormat[K, V]](path: String)
(implicit km: ClassTag[K], vm: ClassTag[V], fm: ClassTag[F]): RDD[(K, V)] = withScope {
hadoopFile[K, V, F](path, defaultMinPartitions)
}
/** Get an RDD for a Hadoop file with an arbitrary new API InputFormat. */
def newAPIHadoopFile[K, V, F <: NewInputFormat[K, V]]
(path: String)
(implicit km: ClassTag[K], vm: ClassTag[V], fm: ClassTag[F]): RDD[(K, V)] = withScope {
newAPIHadoopFile(
path,
fm.runtimeClass.asInstanceOf[Class[F]],
km.runtimeClass.asInstanceOf[Class[K]],
vm.runtimeClass.asInstanceOf[Class[V]])
}
/**
* Get an RDD for a given Hadoop file with an arbitrary new API InputFormat
* and extra configuration options to pass to the input format.
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def newAPIHadoopFile[K, V, F <: NewInputFormat[K, V]](
path: String,
fClass: Class[F],
kClass: Class[K],
vClass: Class[V],
conf: Configuration = hadoopConfiguration): RDD[(K, V)] = withScope {
assertNotStopped()
// This is a hack to enforce loading hdfs-site.xml.
// See SPARK-11227 for details.
FileSystem.getLocal(hadoopConfiguration)
// The call to NewHadoopJob automatically adds security credentials to conf,
// so we don't need to explicitly add them ourselves
val job = NewHadoopJob.getInstance(conf)
// Use setInputPaths so that newAPIHadoopFile aligns with hadoopFile/textFile in taking
// comma separated files as input. (see SPARK-7155)
NewFileInputFormat.setInputPaths(job, path)
val updatedConf = job.getConfiguration
new NewHadoopRDD(this, fClass, kClass, vClass, updatedConf).setName(path)
}
/**
* Get an RDD for a given Hadoop file with an arbitrary new API InputFormat
* and extra configuration options to pass to the input format.
*
* @param conf Configuration for setting up the dataset. Note: This will be put into a Broadcast.
* Therefore if you plan to reuse this conf to create multiple RDDs, you need to make
* sure you won't modify the conf. A safe approach is always creating a new conf for
* a new RDD.
* @param fClass Class of the InputFormat
* @param kClass Class of the keys
* @param vClass Class of the values
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def newAPIHadoopRDD[K, V, F <: NewInputFormat[K, V]](
conf: Configuration = hadoopConfiguration,
fClass: Class[F],
kClass: Class[K],
vClass: Class[V]): RDD[(K, V)] = withScope {
assertNotStopped()
// This is a hack to enforce loading hdfs-site.xml.
// See SPARK-11227 for details.
FileSystem.getLocal(conf)
// Add necessary security credentials to the JobConf. Required to access secure HDFS.
val jconf = new JobConf(conf)
SparkHadoopUtil.get.addCredentials(jconf)
new NewHadoopRDD(this, fClass, kClass, vClass, jconf)
}
/**
* Get an RDD for a Hadoop SequenceFile with given key and value types.
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def sequenceFile[K, V](path: String,
keyClass: Class[K],
valueClass: Class[V],
minPartitions: Int
): RDD[(K, V)] = withScope {
assertNotStopped()
val inputFormatClass = classOf[SequenceFileInputFormat[K, V]]
hadoopFile(path, inputFormatClass, keyClass, valueClass, minPartitions)
}
/**
* Get an RDD for a Hadoop SequenceFile with given key and value types.
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def sequenceFile[K, V](
path: String,
keyClass: Class[K],
valueClass: Class[V]): RDD[(K, V)] = withScope {
assertNotStopped()
sequenceFile(path, keyClass, valueClass, defaultMinPartitions)
}
/**
* Version of sequenceFile() for types implicitly convertible to Writables through a
* WritableConverter. For example, to access a SequenceFile where the keys are Text and the
* values are IntWritable, you could simply write
* {{{
* sparkContext.sequenceFile[String, Int](path, ...)
* }}}
*
* WritableConverters are provided in a somewhat strange way (by an implicit function) to support
* both subclasses of Writable and types for which we define a converter (e.g. Int to
* IntWritable). The most natural thing would've been to have implicit objects for the
* converters, but then we couldn't have an object for every subclass of Writable (you can't
* have a parameterized singleton object). We use functions instead to create a new converter
* for the appropriate type. In addition, we pass the converter a ClassTag of its type to
* allow it to figure out the Writable class to use in the subclass case.
*
* @note Because Hadoop's RecordReader class re-uses the same Writable object for each
* record, directly caching the returned RDD or directly passing it to an aggregation or shuffle
* operation will create many references to the same object.
* If you plan to directly cache, sort, or aggregate Hadoop writable objects, you should first
* copy them using a `map` function.
*/
def sequenceFile[K, V]
(path: String, minPartitions: Int = defaultMinPartitions)
(implicit km: ClassTag[K], vm: ClassTag[V],
kcf: () => WritableConverter[K], vcf: () => WritableConverter[V]): RDD[(K, V)] = {
withScope {
assertNotStopped()
val kc = clean(kcf)()
val vc = clean(vcf)()
val format = classOf[SequenceFileInputFormat[Writable, Writable]]
val writables = hadoopFile(path, format,
kc.writableClass(km).asInstanceOf[Class[Writable]],
vc.writableClass(vm).asInstanceOf[Class[Writable]], minPartitions)
writables.map { case (k, v) => (kc.convert(k), vc.convert(v)) }
}
}
/**
* Load an RDD saved as a SequenceFile containing serialized objects, with NullWritable keys and
* BytesWritable values that contain a serialized partition. This is still an experimental
* storage format and may not be supported exactly as is in future Spark releases. It will also
* be pretty slow if you use the default serializer (Java serialization),
* though the nice thing about it is that there's very little effort required to save arbitrary
* objects.
*/
def objectFile[T: ClassTag](
path: String,
minPartitions: Int = defaultMinPartitions): RDD[T] = withScope {
assertNotStopped()
sequenceFile(path, classOf[NullWritable], classOf[BytesWritable], minPartitions)
.flatMap(x => Utils.deserialize[Array[T]](x._2.getBytes, Utils.getContextOrSparkClassLoader))
}
protected[spark] def checkpointFile[T: ClassTag](path: String): RDD[T] = withScope {
new ReliableCheckpointRDD[T](this, path)
}
/** Build the union of a list of RDDs. */
def union[T: ClassTag](rdds: Seq[RDD[T]]): RDD[T] = withScope {
val partitioners = rdds.flatMap(_.partitioner).toSet
if (rdds.forall(_.partitioner.isDefined) && partitioners.size == 1) {
new PartitionerAwareUnionRDD(this, rdds)
} else {
new UnionRDD(this, rdds)
}
}
/** Build the union of a list of RDDs passed as variable-length arguments. */
def union[T: ClassTag](first: RDD[T], rest: RDD[T]*): RDD[T] = withScope {
union(Seq(first) ++ rest)
}
/** Get an RDD that has no partitions or elements. */
def emptyRDD[T: ClassTag]: RDD[T] = new EmptyRDD[T](this)
// Methods for creating shared variables
/**
* Create an [[org.apache.spark.Accumulator]] variable of a given type, which tasks can "add"
* values to using the `+=` method. Only the driver can access the accumulator's `value`.
*/
@deprecated("use AccumulatorV2", "2.0.0")
def accumulator[T](initialValue: T)(implicit param: AccumulatorParam[T]): Accumulator[T] = {
val acc = new Accumulator(initialValue, param)
cleaner.foreach(_.registerAccumulatorForCleanup(acc.newAcc))
acc
}
/**
* Create an [[org.apache.spark.Accumulator]] variable of a given type, with a name for display
* in the Spark UI. Tasks can "add" values to the accumulator using the `+=` method. Only the
* driver can access the accumulator's `value`.
*/
@deprecated("use AccumulatorV2", "2.0.0")
def accumulator[T](initialValue: T, name: String)(implicit param: AccumulatorParam[T])
: Accumulator[T] = {
val acc = new Accumulator(initialValue, param, Option(name))
cleaner.foreach(_.registerAccumulatorForCleanup(acc.newAcc))
acc
}
/**
* Create an [[org.apache.spark.Accumulable]] shared variable, to which tasks can add values
* with `+=`. Only the driver can access the accumulable's `value`.
* @tparam R accumulator result type
* @tparam T type that can be added to the accumulator
*/
@deprecated("use AccumulatorV2", "2.0.0")
def accumulable[R, T](initialValue: R)(implicit param: AccumulableParam[R, T])
: Accumulable[R, T] = {
val acc = new Accumulable(initialValue, param)
cleaner.foreach(_.registerAccumulatorForCleanup(acc.newAcc))
acc
}
/**
* Create an [[org.apache.spark.Accumulable]] shared variable, with a name for display in the
* Spark UI. Tasks can add values to the accumulable using the `+=` operator. Only the driver can
* access the accumulable's `value`.
* @tparam R accumulator result type
* @tparam T type that can be added to the accumulator
*/
@deprecated("use AccumulatorV2", "2.0.0")
def accumulable[R, T](initialValue: R, name: String)(implicit param: AccumulableParam[R, T])
: Accumulable[R, T] = {
val acc = new Accumulable(initialValue, param, Option(name))
cleaner.foreach(_.registerAccumulatorForCleanup(acc.newAcc))
acc
}
/**
* Create an accumulator from a "mutable collection" type.
*
* Growable and TraversableOnce are the standard APIs that guarantee += and ++=, implemented by
* standard mutable collections. So you can use this with mutable Map, Set, etc.
*/
@deprecated("use AccumulatorV2", "2.0.0")
def accumulableCollection[R <% Growable[T] with TraversableOnce[T] with Serializable: ClassTag, T]
(initialValue: R): Accumulable[R, T] = {
val param = new GrowableAccumulableParam[R, T]
val acc = new Accumulable(initialValue, param)
cleaner.foreach(_.registerAccumulatorForCleanup(acc.newAcc))
acc
}
/**
* Register the given accumulator.
*
* @note Accumulators must be registered before use, or it will throw exception.
*/
def register(acc: AccumulatorV2[_, _]): Unit = {
acc.register(this)
}
/**
* Register the given accumulator with given name.
*
* @note Accumulators must be registered before use, or it will throw exception.
*/
def register(acc: AccumulatorV2[_, _], name: String): Unit = {
acc.register(this, name = Option(name))
}
/**
* Create and register a long accumulator, which starts with 0 and accumulates inputs by `add`.
*/
def longAccumulator: LongAccumulator = {
val acc = new LongAccumulator
register(acc)
acc
}
/**
* Create and register a long accumulator, which starts with 0 and accumulates inputs by `add`.
*/
def longAccumulator(name: String): LongAccumulator = {
val acc = new LongAccumulator
register(acc, name)
acc
}
/**
* Create and register a double accumulator, which starts with 0 and accumulates inputs by `add`.
*/
def doubleAccumulator: DoubleAccumulator = {
val acc = new DoubleAccumulator
register(acc)
acc
}
/**
* Create and register a double accumulator, which starts with 0 and accumulates inputs by `add`.
*/
def doubleAccumulator(name: String): DoubleAccumulator = {
val acc = new DoubleAccumulator
register(acc, name)
acc
}
/**
* Create and register a `CollectionAccumulator`, which starts with empty list and accumulates
* inputs by adding them into the list.
*/
def collectionAccumulator[T]: CollectionAccumulator[T] = {
val acc = new CollectionAccumulator[T]
register(acc)
acc
}
/**
* Create and register a `CollectionAccumulator`, which starts with empty list and accumulates
* inputs by adding them into the list.
*/
def collectionAccumulator[T](name: String): CollectionAccumulator[T] = {
val acc = new CollectionAccumulator[T]
register(acc, name)
acc
}
/**
* Broadcast a read-only variable to the cluster, returning a
* [[org.apache.spark.broadcast.Broadcast]] object for reading it in distributed functions.
* The variable will be sent to each cluster only once.
*/
def broadcast[T: ClassTag](value: T): Broadcast[T] = {
assertNotStopped()
require(!classOf[RDD[_]].isAssignableFrom(classTag[T].runtimeClass),
"Can not directly broadcast RDDs; instead, call collect() and broadcast the result.")
val bc = env.broadcastManager.newBroadcast[T](value, isLocal)
val callSite = getCallSite
logInfo("Created broadcast " + bc.id + " from " + callSite.shortForm)
cleaner.foreach(_.registerBroadcastForCleanup(bc))
bc
}
/**
* Add a file to be downloaded with this Spark job on every node.
* The `path` passed can be either a local file, a file in HDFS (or other Hadoop-supported
* filesystems), or an HTTP, HTTPS or FTP URI. To access the file in Spark jobs,
* use `SparkFiles.get(fileName)` to find its download location.
*/
def addFile(path: String): Unit = {
addFile(path, false)
}
/**
* Returns a list of file paths that are added to resources.
*/
def listFiles(): Seq[String] = addedFiles.keySet.toSeq
/**
* Add a file to be downloaded with this Spark job on every node.
* The `path` passed can be either a local file, a file in HDFS (or other Hadoop-supported
* filesystems), or an HTTP, HTTPS or FTP URI. To access the file in Spark jobs,
* use `SparkFiles.get(fileName)` to find its download location.
*
* A directory can be given if the recursive option is set to true. Currently directories are only
* supported for Hadoop-supported filesystems.
*/
def addFile(path: String, recursive: Boolean): Unit = {
val uri = new Path(path).toUri
val schemeCorrectedPath = uri.getScheme match {
case null | "local" => new File(path).getCanonicalFile.toURI.toString
case _ => path
}
val hadoopPath = new Path(schemeCorrectedPath)
val scheme = new URI(schemeCorrectedPath).getScheme
if (!Array("http", "https", "ftp").contains(scheme)) {
val fs = hadoopPath.getFileSystem(hadoopConfiguration)
val isDir = fs.getFileStatus(hadoopPath).isDirectory
if (!isLocal && scheme == "file" && isDir) {
throw new SparkException(s"addFile does not support local directories when not running " +
"local mode.")
}
if (!recursive && isDir) {
throw new SparkException(s"Added file $hadoopPath is a directory and recursive is not " +
"turned on.")
}
} else {
// SPARK-17650: Make sure this is a valid URL before adding it to the list of dependencies
Utils.validateURL(uri)
}
val key = if (!isLocal && scheme == "file") {
env.rpcEnv.fileServer.addFile(new File(uri.getPath))
} else {
schemeCorrectedPath
}
val timestamp = System.currentTimeMillis
if (addedFiles.putIfAbsent(key, timestamp).isEmpty) {
logInfo(s"Added file $path at $key with timestamp $timestamp")
// Fetch the file locally so that closures which are run on the driver can still use the
// SparkFiles API to access files.
Utils.fetchFile(uri.toString, new File(SparkFiles.getRootDirectory()), conf,
env.securityManager, hadoopConfiguration, timestamp, useCache = false)
postEnvironmentUpdate()
}
}
/**
* :: DeveloperApi ::
* Register a listener to receive up-calls from events that happen during execution.
*/
@DeveloperApi
def addSparkListener(listener: SparkListenerInterface) {
listenerBus.addListener(listener)
}
private[spark] def getExecutorIds(): Seq[String] = {
schedulerBackend match {
case b: CoarseGrainedSchedulerBackend =>
b.getExecutorIds()
case _ =>
logWarning("Requesting executors is only supported in coarse-grained mode")
Nil
}
}
/**
* Update the cluster manager on our scheduling needs. Three bits of information are included
* to help it make decisions.
* @param numExecutors The total number of executors we'd like to have. The cluster manager
* shouldn't kill any running executor to reach this number, but,
* if all existing executors were to die, this is the number of executors
* we'd want to be allocated.
* @param localityAwareTasks The number of tasks in all active stages that have a locality
* preferences. This includes running, pending, and completed tasks.
* @param hostToLocalTaskCount A map of hosts to the number of tasks from all active stages
* that would like to like to run on that host.
* This includes running, pending, and completed tasks.
* @return whether the request is acknowledged by the cluster manager.
*/
@DeveloperApi
def requestTotalExecutors(
numExecutors: Int,
localityAwareTasks: Int,
hostToLocalTaskCount: scala.collection.immutable.Map[String, Int]
): Boolean = {
schedulerBackend match {
case b: CoarseGrainedSchedulerBackend =>
b.requestTotalExecutors(numExecutors, localityAwareTasks, hostToLocalTaskCount)
case _ =>
logWarning("Requesting executors is only supported in coarse-grained mode")
false
}
}
/**
* :: DeveloperApi ::
* Request an additional number of executors from the cluster manager.
* @return whether the request is received.
*/
@DeveloperApi
def requestExecutors(numAdditionalExecutors: Int): Boolean = {
schedulerBackend match {
case b: CoarseGrainedSchedulerBackend =>
b.requestExecutors(numAdditionalExecutors)
case _ =>
logWarning("Requesting executors is only supported in coarse-grained mode")
false
}
}
/**
* :: DeveloperApi ::
* Request that the cluster manager kill the specified executors.
*
* @note This is an indication to the cluster manager that the application wishes to adjust
* its resource usage downwards. If the application wishes to replace the executors it kills
* through this method with new ones, it should follow up explicitly with a call to
* {{SparkContext#requestExecutors}}.
*
* @return whether the request is received.
*/
@DeveloperApi
def killExecutors(executorIds: Seq[String]): Boolean = {
schedulerBackend match {
case b: CoarseGrainedSchedulerBackend =>
b.killExecutors(executorIds, replace = false, force = true).nonEmpty
case _ =>
logWarning("Killing executors is only supported in coarse-grained mode")
false
}
}
/**
* :: DeveloperApi ::
* Request that the cluster manager kill the specified executor.
*
* @note This is an indication to the cluster manager that the application wishes to adjust
* its resource usage downwards. If the application wishes to replace the executor it kills
* through this method with a new one, it should follow up explicitly with a call to
* {{SparkContext#requestExecutors}}.
*
* @return whether the request is received.
*/
@DeveloperApi
def killExecutor(executorId: String): Boolean = killExecutors(Seq(executorId))
/**
* Request that the cluster manager kill the specified executor without adjusting the
* application resource requirements.
*
* The effect is that a new executor will be launched in place of the one killed by
* this request. This assumes the cluster manager will automatically and eventually
* fulfill all missing application resource requests.
*
* @note The replace is by no means guaranteed; another application on the same cluster
* can steal the window of opportunity and acquire this application's resources in the
* mean time.
*
* @return whether the request is received.
*/
private[spark] def killAndReplaceExecutor(executorId: String): Boolean = {
schedulerBackend match {
case b: CoarseGrainedSchedulerBackend =>
b.killExecutors(Seq(executorId), replace = true, force = true).nonEmpty
case _ =>
logWarning("Killing executors is only supported in coarse-grained mode")
false
}
}
/** The version of Spark on which this application is running. */
def version: String = SPARK_VERSION
/**
* Return a map from the slave to the max memory available for caching and the remaining
* memory available for caching.
*/
def getExecutorMemoryStatus: Map[String, (Long, Long)] = {
assertNotStopped()
env.blockManager.master.getMemoryStatus.map { case(blockManagerId, mem) =>
(blockManagerId.host + ":" + blockManagerId.port, mem)
}
}
/**
* :: DeveloperApi ::
* Return information about what RDDs are cached, if they are in mem or on disk, how much space
* they take, etc.
*/
@DeveloperApi
def getRDDStorageInfo: Array[RDDInfo] = {
getRDDStorageInfo(_ => true)
}
private[spark] def getRDDStorageInfo(filter: RDD[_] => Boolean): Array[RDDInfo] = {
assertNotStopped()
val rddInfos = persistentRdds.values.filter(filter).map(RDDInfo.fromRdd).toArray
StorageUtils.updateRddInfo(rddInfos, getExecutorStorageStatus)
rddInfos.filter(_.isCached)
}
/**
* Returns an immutable map of RDDs that have marked themselves as persistent via cache() call.
*
* @note This does not necessarily mean the caching or computation was successful.
*/
def getPersistentRDDs: Map[Int, RDD[_]] = persistentRdds.toMap
/**
* :: DeveloperApi ::
* Return information about blocks stored in all of the slaves
*/
@DeveloperApi
def getExecutorStorageStatus: Array[StorageStatus] = {
assertNotStopped()
env.blockManager.master.getStorageStatus
}
/**
* :: DeveloperApi ::
* Return pools for fair scheduler
*/
@DeveloperApi
def getAllPools: Seq[Schedulable] = {
assertNotStopped()
// TODO(xiajunluan): We should take nested pools into account
taskScheduler.rootPool.schedulableQueue.asScala.toSeq
}
/**
* :: DeveloperApi ::
* Return the pool associated with the given name, if one exists
*/
@DeveloperApi
def getPoolForName(pool: String): Option[Schedulable] = {
assertNotStopped()
Option(taskScheduler.rootPool.schedulableNameToSchedulable.get(pool))
}
/**
* Return current scheduling mode
*/
def getSchedulingMode: SchedulingMode.SchedulingMode = {
assertNotStopped()
taskScheduler.schedulingMode
}
/**
* Gets the locality information associated with the partition in a particular rdd
* @param rdd of interest
* @param partition to be looked up for locality
* @return list of preferred locations for the partition
*/
private [spark] def getPreferredLocs(rdd: RDD[_], partition: Int): Seq[TaskLocation] = {
dagScheduler.getPreferredLocs(rdd, partition)
}
/**
* Register an RDD to be persisted in memory and/or disk storage
*/
private[spark] def persistRDD(rdd: RDD[_]) {
persistentRdds(rdd.id) = rdd
}
/**
* Unpersist an RDD from memory and/or disk storage
*/
private[spark] def unpersistRDD(rddId: Int, blocking: Boolean = true) {
env.blockManager.master.removeRdd(rddId, blocking)
persistentRdds.remove(rddId)
listenerBus.post(SparkListenerUnpersistRDD(rddId))
}
/**
* Adds a JAR dependency for all tasks to be executed on this SparkContext in the future.
* The `path` passed can be either a local file, a file in HDFS (or other Hadoop-supported
* filesystems), an HTTP, HTTPS or FTP URI, or local:/path for a file on every worker node.
*/
def addJar(path: String) {
if (path == null) {
logWarning("null specified as parameter to addJar")
} else {
var key = ""
if (path.contains("\\")) {
// For local paths with backslashes on Windows, URI throws an exception
key = env.rpcEnv.fileServer.addJar(new File(path))
} else {
val uri = new URI(path)
// SPARK-17650: Make sure this is a valid URL before adding it to the list of dependencies
Utils.validateURL(uri)
key = uri.getScheme match {
// A JAR file which exists only on the driver node
case null | "file" =>
try {
val file = new File(uri.getPath)
if (!file.exists()) {
throw new FileNotFoundException(s"Jar ${file.getAbsolutePath} not found")
}
if (file.isDirectory) {
throw new IllegalArgumentException(
s"Directory ${file.getAbsoluteFile} is not allowed for addJar")
}
env.rpcEnv.fileServer.addJar(new File(uri.getPath))
} catch {
case NonFatal(e) =>
logError(s"Failed to add $path to Spark environment", e)
null
}
// A JAR file which exists locally on every worker node
case "local" =>
"file:" + uri.getPath
case _ =>
path
}
}
if (key != null) {
val timestamp = System.currentTimeMillis
if (addedJars.putIfAbsent(key, timestamp).isEmpty) {
logInfo(s"Added JAR $path at $key with timestamp $timestamp")
postEnvironmentUpdate()
}
}
}
}
/**
* Returns a list of jar files that are added to resources.
*/
def listJars(): Seq[String] = addedJars.keySet.toSeq
/**
* When stopping SparkContext inside Spark components, it's easy to cause dead-lock since Spark
* may wait for some internal threads to finish. It's better to use this method to stop
* SparkContext instead.
*/
private[spark] def stopInNewThread(): Unit = {
new Thread("stop-spark-context") {
setDaemon(true)
override def run(): Unit = {
try {
SparkContext.this.stop()
} catch {
case e: Throwable =>
logError(e.getMessage, e)
throw e
}
}
}.start()
}
/**
* Shut down the SparkContext.
*/
def stop(): Unit = {
if (LiveListenerBus.withinListenerThread.value) {
throw new SparkException(
s"Cannot stop SparkContext within listener thread of ${LiveListenerBus.name}")
}
// Use the stopping variable to ensure no contention for the stop scenario.
// Still track the stopped variable for use elsewhere in the code.
if (!stopped.compareAndSet(false, true)) {
logInfo("SparkContext already stopped.")
return
}
if (_shutdownHookRef != null) {
ShutdownHookManager.removeShutdownHook(_shutdownHookRef)
}
Utils.tryLogNonFatalError {
postApplicationEnd()
}
Utils.tryLogNonFatalError {
_ui.foreach(_.stop())
}
if (env != null) {
Utils.tryLogNonFatalError {
env.metricsSystem.report()
}
}
Utils.tryLogNonFatalError {
_cleaner.foreach(_.stop())
}
Utils.tryLogNonFatalError {
_executorAllocationManager.foreach(_.stop())
}
if (_listenerBusStarted) {
Utils.tryLogNonFatalError {
listenerBus.stop()
_listenerBusStarted = false
}
}
Utils.tryLogNonFatalError {
_eventLogger.foreach(_.stop())
}
if (_dagScheduler != null) {
Utils.tryLogNonFatalError {
_dagScheduler.stop()
}
_dagScheduler = null
}
if (env != null && _heartbeatReceiver != null) {
Utils.tryLogNonFatalError {
env.rpcEnv.stop(_heartbeatReceiver)
}
}
Utils.tryLogNonFatalError {
_progressBar.foreach(_.stop())
}
_taskScheduler = null
// TODO: Cache.stop()?
if (_env != null) {
Utils.tryLogNonFatalError {
_env.stop()
}
SparkEnv.set(null)
}
// Unset YARN mode system env variable, to allow switching between cluster types.
System.clearProperty("SPARK_YARN_MODE")
SparkContext.clearActiveContext()
logInfo("Successfully stopped SparkContext")
}
/**
* Get Spark's home location from either a value set through the constructor,
* or the spark.home Java property, or the SPARK_HOME environment variable
* (in that order of preference). If neither of these is set, return None.
*/
private[spark] def getSparkHome(): Option[String] = {
conf.getOption("spark.home").orElse(Option(System.getenv("SPARK_HOME")))
}
/**
* Set the thread-local property for overriding the call sites
* of actions and RDDs.
*/
def setCallSite(shortCallSite: String) {
setLocalProperty(CallSite.SHORT_FORM, shortCallSite)
}
/**
* Set the thread-local property for overriding the call sites
* of actions and RDDs.
*/
private[spark] def setCallSite(callSite: CallSite) {
setLocalProperty(CallSite.SHORT_FORM, callSite.shortForm)
setLocalProperty(CallSite.LONG_FORM, callSite.longForm)
}
/**
* Clear the thread-local property for overriding the call sites
* of actions and RDDs.
*/
def clearCallSite() {
setLocalProperty(CallSite.SHORT_FORM, null)
setLocalProperty(CallSite.LONG_FORM, null)
}
/**
* Capture the current user callsite and return a formatted version for printing. If the user
* has overridden the call site using `setCallSite()`, this will return the user's version.
*/
private[spark] def getCallSite(): CallSite = {
lazy val callSite = Utils.getCallSite()
CallSite(
Option(getLocalProperty(CallSite.SHORT_FORM)).getOrElse(callSite.shortForm),
Option(getLocalProperty(CallSite.LONG_FORM)).getOrElse(callSite.longForm)
)
}
/**
* Run a function on a given set of partitions in an RDD and pass the results to the given
* handler function. This is the main entry point for all actions in Spark.
*/
def runJob[T, U: ClassTag](
rdd: RDD[T],
func: (TaskContext, Iterator[T]) => U,
partitions: Seq[Int],
resultHandler: (Int, U) => Unit): Unit = {
if (stopped.get()) {
throw new IllegalStateException("SparkContext has been shutdown")
}
val callSite = getCallSite
val cleanedFunc = clean(func)
logInfo("Starting job: " + callSite.shortForm)
if (conf.getBoolean("spark.logLineage", false)) {
logInfo("RDD's recursive dependencies:\n" + rdd.toDebugString)
}
dagScheduler.runJob(rdd, cleanedFunc, partitions, callSite, resultHandler, localProperties.get)
progressBar.foreach(_.finishAll())
rdd.doCheckpoint()
}
/**
* Run a function on a given set of partitions in an RDD and return the results as an array.
*/
def runJob[T, U: ClassTag](
rdd: RDD[T],
func: (TaskContext, Iterator[T]) => U,
partitions: Seq[Int]): Array[U] = {
val results = new Array[U](partitions.size)
runJob[T, U](rdd, func, partitions, (index, res) => results(index) = res)
results
}
/**
* Run a job on a given set of partitions of an RDD, but take a function of type
* `Iterator[T] => U` instead of `(TaskContext, Iterator[T]) => U`.
*/
def runJob[T, U: ClassTag](
rdd: RDD[T],
func: Iterator[T] => U,
partitions: Seq[Int]): Array[U] = {
val cleanedFunc = clean(func)
runJob(rdd, (ctx: TaskContext, it: Iterator[T]) => cleanedFunc(it), partitions)
}
/**
* Run a job on all partitions in an RDD and return the results in an array.
*/
def runJob[T, U: ClassTag](rdd: RDD[T], func: (TaskContext, Iterator[T]) => U): Array[U] = {
runJob(rdd, func, 0 until rdd.partitions.length)
}
/**
* Run a job on all partitions in an RDD and return the results in an array.
*/
def runJob[T, U: ClassTag](rdd: RDD[T], func: Iterator[T] => U): Array[U] = {
runJob(rdd, func, 0 until rdd.partitions.length)
}
/**
* Run a job on all partitions in an RDD and pass the results to a handler function.
*/
def runJob[T, U: ClassTag](
rdd: RDD[T],
processPartition: (TaskContext, Iterator[T]) => U,
resultHandler: (Int, U) => Unit)
{
runJob[T, U](rdd, processPartition, 0 until rdd.partitions.length, resultHandler)
}
/**
* Run a job on all partitions in an RDD and pass the results to a handler function.
*/
def runJob[T, U: ClassTag](
rdd: RDD[T],
processPartition: Iterator[T] => U,
resultHandler: (Int, U) => Unit)
{
val processFunc = (context: TaskContext, iter: Iterator[T]) => processPartition(iter)
runJob[T, U](rdd, processFunc, 0 until rdd.partitions.length, resultHandler)
}
/**
* :: DeveloperApi ::
* Run a job that can return approximate results.
*/
@DeveloperApi
def runApproximateJob[T, U, R](
rdd: RDD[T],
func: (TaskContext, Iterator[T]) => U,
evaluator: ApproximateEvaluator[U, R],
timeout: Long): PartialResult[R] = {
assertNotStopped()
val callSite = getCallSite
logInfo("Starting job: " + callSite.shortForm)
val start = System.nanoTime
val cleanedFunc = clean(func)
val result = dagScheduler.runApproximateJob(rdd, cleanedFunc, evaluator, callSite, timeout,
localProperties.get)
logInfo(
"Job finished: " + callSite.shortForm + ", took " + (System.nanoTime - start) / 1e9 + " s")
result
}
/**
* Submit a job for execution and return a FutureJob holding the result.
*/
def submitJob[T, U, R](
rdd: RDD[T],
processPartition: Iterator[T] => U,
partitions: Seq[Int],
resultHandler: (Int, U) => Unit,
resultFunc: => R): SimpleFutureAction[R] =
{
assertNotStopped()
val cleanF = clean(processPartition)
val callSite = getCallSite
val waiter = dagScheduler.submitJob(
rdd,
(context: TaskContext, iter: Iterator[T]) => cleanF(iter),
partitions,
callSite,
resultHandler,
localProperties.get)
new SimpleFutureAction(waiter, resultFunc)
}
/**
* Submit a map stage for execution. This is currently an internal API only, but might be
* promoted to DeveloperApi in the future.
*/
private[spark] def submitMapStage[K, V, C](dependency: ShuffleDependency[K, V, C])
: SimpleFutureAction[MapOutputStatistics] = {
assertNotStopped()
val callSite = getCallSite()
var result: MapOutputStatistics = null
val waiter = dagScheduler.submitMapStage(
dependency,
(r: MapOutputStatistics) => { result = r },
callSite,
localProperties.get)
new SimpleFutureAction[MapOutputStatistics](waiter, result)
}
/**
* Cancel active jobs for the specified group. See `org.apache.spark.SparkContext.setJobGroup`
* for more information.
*/
def cancelJobGroup(groupId: String) {
assertNotStopped()
dagScheduler.cancelJobGroup(groupId)
}
/** Cancel all jobs that have been scheduled or are running. */
def cancelAllJobs() {
assertNotStopped()
dagScheduler.cancelAllJobs()
}
/**
* Cancel a given job if it's scheduled or running.
*
* @param jobId the job ID to cancel
* @note Throws `InterruptedException` if the cancel message cannot be sent
*/
def cancelJob(jobId: Int) {
dagScheduler.cancelJob(jobId)
}
/**
* Cancel a given stage and all jobs associated with it.
*
* @param stageId the stage ID to cancel
* @note Throws `InterruptedException` if the cancel message cannot be sent
*/
def cancelStage(stageId: Int) {
dagScheduler.cancelStage(stageId)
}
/**
* Clean a closure to make it ready to serialized and send to tasks
* (removes unreferenced variables in $outer's, updates REPL variables)
* If <tt>checkSerializable</tt> is set, <tt>clean</tt> will also proactively
* check to see if <tt>f</tt> is serializable and throw a <tt>SparkException</tt>
* if not.
*
* @param f the closure to clean
* @param checkSerializable whether or not to immediately check <tt>f</tt> for serializability
* @throws SparkException if <tt>checkSerializable</tt> is set but <tt>f</tt> is not
* serializable
*/
private[spark] def clean[F <: AnyRef](f: F, checkSerializable: Boolean = true): F = {
ClosureCleaner.clean(f, checkSerializable)
f
}
/**
* Set the directory under which RDDs are going to be checkpointed. The directory must
* be a HDFS path if running on a cluster.
*/
def setCheckpointDir(directory: String) {
// If we are running on a cluster, log a warning if the directory is local.
// Otherwise, the driver may attempt to reconstruct the checkpointed RDD from
// its own local file system, which is incorrect because the checkpoint files
// are actually on the executor machines.
if (!isLocal && Utils.nonLocalPaths(directory).isEmpty) {
logWarning("Spark is not running in local mode, therefore the checkpoint directory " +
s"must not be on the local filesystem. Directory '$directory' " +
"appears to be on the local filesystem.")
}
checkpointDir = Option(directory).map { dir =>
val path = new Path(dir, UUID.randomUUID().toString)
val fs = path.getFileSystem(hadoopConfiguration)
fs.mkdirs(path)
fs.getFileStatus(path).getPath.toString
}
}
def getCheckpointDir: Option[String] = checkpointDir
/** Default level of parallelism to use when not given by user (e.g. parallelize and makeRDD). */
def defaultParallelism: Int = {
assertNotStopped()
taskScheduler.defaultParallelism
}
/**
* Default min number of partitions for Hadoop RDDs when not given by user
* Notice that we use math.min so the "defaultMinPartitions" cannot be higher than 2.
* The reasons for this are discussed in https://github.com/mesos/spark/pull/718
*/
def defaultMinPartitions: Int = math.min(defaultParallelism, 2)
private val nextShuffleId = new AtomicInteger(0)
private[spark] def newShuffleId(): Int = nextShuffleId.getAndIncrement()
private val nextRddId = new AtomicInteger(0)
/** Register a new RDD, returning its RDD ID */
private[spark] def newRddId(): Int = nextRddId.getAndIncrement()
/**
* Registers listeners specified in spark.extraListeners, then starts the listener bus.
* This should be called after all internal listeners have been registered with the listener bus
* (e.g. after the web UI and event logging listeners have been registered).
*/
private def setupAndStartListenerBus(): Unit = {
// Use reflection to instantiate listeners specified via `spark.extraListeners`
try {
val listenerClassNames: Seq[String] =
conf.get("spark.extraListeners", "").split(',').map(_.trim).filter(_ != "")
for (className <- listenerClassNames) {
// Use reflection to find the right constructor
val constructors = {
val listenerClass = Utils.classForName(className)
listenerClass
.getConstructors
.asInstanceOf[Array[Constructor[_ <: SparkListenerInterface]]]
}
val constructorTakingSparkConf = constructors.find { c =>
c.getParameterTypes.sameElements(Array(classOf[SparkConf]))
}
lazy val zeroArgumentConstructor = constructors.find { c =>
c.getParameterTypes.isEmpty
}
val listener: SparkListenerInterface = {
if (constructorTakingSparkConf.isDefined) {
constructorTakingSparkConf.get.newInstance(conf)
} else if (zeroArgumentConstructor.isDefined) {
zeroArgumentConstructor.get.newInstance()
} else {
throw new SparkException(
s"$className did not have a zero-argument constructor or a" +
" single-argument constructor that accepts SparkConf. Note: if the class is" +
" defined inside of another Scala class, then its constructors may accept an" +
" implicit parameter that references the enclosing class; in this case, you must" +
" define the listener as a top-level class in order to prevent this extra" +
" parameter from breaking Spark's ability to find a valid constructor.")
}
}
listenerBus.addListener(listener)
logInfo(s"Registered listener $className")
}
} catch {
case e: Exception =>
try {
stop()
} finally {
throw new SparkException(s"Exception when registering SparkListener", e)
}
}
listenerBus.start()
_listenerBusStarted = true
}
/** Post the application start event */
private def postApplicationStart() {
// Note: this code assumes that the task scheduler has been initialized and has contacted
// the cluster manager to get an application ID (in case the cluster manager provides one).
listenerBus.post(SparkListenerApplicationStart(appName, Some(applicationId),
startTime, sparkUser, applicationAttemptId, schedulerBackend.getDriverLogUrls))
}
/** Post the application end event */
private def postApplicationEnd() {
listenerBus.post(SparkListenerApplicationEnd(System.currentTimeMillis))
}
/** Post the environment update event once the task scheduler is ready */
private def postEnvironmentUpdate() {
if (taskScheduler != null) {
val schedulingMode = getSchedulingMode.toString
val addedJarPaths = addedJars.keys.toSeq
val addedFilePaths = addedFiles.keys.toSeq
val environmentDetails = SparkEnv.environmentDetails(conf, schedulingMode, addedJarPaths,
addedFilePaths)
val environmentUpdate = SparkListenerEnvironmentUpdate(environmentDetails)
listenerBus.post(environmentUpdate)
}
}
// In order to prevent multiple SparkContexts from being active at the same time, mark this
// context as having finished construction.
// NOTE: this must be placed at the end of the SparkContext constructor.
SparkContext.setActiveContext(this, allowMultipleContexts)
}
/**
* The SparkContext object contains a number of implicit conversions and parameters for use with
* various Spark features.
*/
object SparkContext extends Logging {
private val VALID_LOG_LEVELS =
Set("ALL", "DEBUG", "ERROR", "FATAL", "INFO", "OFF", "TRACE", "WARN")
/**
* Lock that guards access to global variables that track SparkContext construction.
*/
private val SPARK_CONTEXT_CONSTRUCTOR_LOCK = new Object()
/**
* The active, fully-constructed SparkContext. If no SparkContext is active, then this is `null`.
*
* Access to this field is guarded by SPARK_CONTEXT_CONSTRUCTOR_LOCK.
*/
private val activeContext: AtomicReference[SparkContext] =
new AtomicReference[SparkContext](null)
/**
* Points to a partially-constructed SparkContext if some thread is in the SparkContext
* constructor, or `None` if no SparkContext is being constructed.
*
* Access to this field is guarded by SPARK_CONTEXT_CONSTRUCTOR_LOCK
*/
private var contextBeingConstructed: Option[SparkContext] = None
/**
* Called to ensure that no other SparkContext is running in this JVM.
*
* Throws an exception if a running context is detected and logs a warning if another thread is
* constructing a SparkContext. This warning is necessary because the current locking scheme
* prevents us from reliably distinguishing between cases where another context is being
* constructed and cases where another constructor threw an exception.
*/
private def assertNoOtherContextIsRunning(
sc: SparkContext,
allowMultipleContexts: Boolean): Unit = {
SPARK_CONTEXT_CONSTRUCTOR_LOCK.synchronized {
Option(activeContext.get()).filter(_ ne sc).foreach { ctx =>
val errMsg = "Only one SparkContext may be running in this JVM (see SPARK-2243)." +
" To ignore this error, set spark.driver.allowMultipleContexts = true. " +
s"The currently running SparkContext was created at:\n${ctx.creationSite.longForm}"
val exception = new SparkException(errMsg)
if (allowMultipleContexts) {
logWarning("Multiple running SparkContexts detected in the same JVM!", exception)
} else {
throw exception
}
}
contextBeingConstructed.filter(_ ne sc).foreach { otherContext =>
// Since otherContext might point to a partially-constructed context, guard against
// its creationSite field being null:
val otherContextCreationSite =
Option(otherContext.creationSite).map(_.longForm).getOrElse("unknown location")
val warnMsg = "Another SparkContext is being constructed (or threw an exception in its" +
" constructor). This may indicate an error, since only one SparkContext may be" +
" running in this JVM (see SPARK-2243)." +
s" The other SparkContext was created at:\n$otherContextCreationSite"
logWarning(warnMsg)
}
}
}
/**
* This function may be used to get or instantiate a SparkContext and register it as a
* singleton object. Because we can only have one active SparkContext per JVM,
* this is useful when applications may wish to share a SparkContext.
*
* @note This function cannot be used to create multiple SparkContext instances
* even if multiple contexts are allowed.
*/
def getOrCreate(config: SparkConf): SparkContext = {
// Synchronize to ensure that multiple create requests don't trigger an exception
// from assertNoOtherContextIsRunning within setActiveContext
SPARK_CONTEXT_CONSTRUCTOR_LOCK.synchronized {
if (activeContext.get() == null) {
setActiveContext(new SparkContext(config), allowMultipleContexts = false)
} else {
if (config.getAll.nonEmpty) {
logWarning("Using an existing SparkContext; some configuration may not take effect.")
}
}
activeContext.get()
}
}
/**
* This function may be used to get or instantiate a SparkContext and register it as a
* singleton object. Because we can only have one active SparkContext per JVM,
* this is useful when applications may wish to share a SparkContext.
*
* This method allows not passing a SparkConf (useful if just retrieving).
*
* @note This function cannot be used to create multiple SparkContext instances
* even if multiple contexts are allowed.
*/
def getOrCreate(): SparkContext = {
SPARK_CONTEXT_CONSTRUCTOR_LOCK.synchronized {
if (activeContext.get() == null) {
setActiveContext(new SparkContext(), allowMultipleContexts = false)
}
activeContext.get()
}
}
/** Return the current active [[SparkContext]] if any. */
private[spark] def getActive: Option[SparkContext] = {
SPARK_CONTEXT_CONSTRUCTOR_LOCK.synchronized {
Option(activeContext.get())
}
}
/**
* Called at the beginning of the SparkContext constructor to ensure that no SparkContext is
* running. Throws an exception if a running context is detected and logs a warning if another
* thread is constructing a SparkContext. This warning is necessary because the current locking
* scheme prevents us from reliably distinguishing between cases where another context is being
* constructed and cases where another constructor threw an exception.
*/
private[spark] def markPartiallyConstructed(
sc: SparkContext,
allowMultipleContexts: Boolean): Unit = {
SPARK_CONTEXT_CONSTRUCTOR_LOCK.synchronized {
assertNoOtherContextIsRunning(sc, allowMultipleContexts)
contextBeingConstructed = Some(sc)
}
}
/**
* Called at the end of the SparkContext constructor to ensure that no other SparkContext has
* raced with this constructor and started.
*/
private[spark] def setActiveContext(
sc: SparkContext,
allowMultipleContexts: Boolean): Unit = {
SPARK_CONTEXT_CONSTRUCTOR_LOCK.synchronized {
assertNoOtherContextIsRunning(sc, allowMultipleContexts)
contextBeingConstructed = None
activeContext.set(sc)
}
}
/**
* Clears the active SparkContext metadata. This is called by `SparkContext#stop()`. It's
* also called in unit tests to prevent a flood of warnings from test suites that don't / can't
* properly clean up their SparkContexts.
*/
private[spark] def clearActiveContext(): Unit = {
SPARK_CONTEXT_CONSTRUCTOR_LOCK.synchronized {
activeContext.set(null)
}
}
private[spark] val SPARK_JOB_DESCRIPTION = "spark.job.description"
private[spark] val SPARK_JOB_GROUP_ID = "spark.jobGroup.id"
private[spark] val SPARK_JOB_INTERRUPT_ON_CANCEL = "spark.job.interruptOnCancel"
private[spark] val RDD_SCOPE_KEY = "spark.rdd.scope"
private[spark] val RDD_SCOPE_NO_OVERRIDE_KEY = "spark.rdd.scope.noOverride"
/**
* Executor id for the driver. In earlier versions of Spark, this was `<driver>`, but this was
* changed to `driver` because the angle brackets caused escaping issues in URLs and XML (see
* SPARK-6716 for more details).
*/
private[spark] val DRIVER_IDENTIFIER = "driver"
/**
* Legacy version of DRIVER_IDENTIFIER, retained for backwards-compatibility.
*/
private[spark] val LEGACY_DRIVER_IDENTIFIER = "<driver>"
private implicit def arrayToArrayWritable[T <% Writable: ClassTag](arr: Traversable[T])
: ArrayWritable = {
def anyToWritable[U <% Writable](u: U): Writable = u
new ArrayWritable(classTag[T].runtimeClass.asInstanceOf[Class[Writable]],
arr.map(x => anyToWritable(x)).toArray)
}
/**
* Find the JAR from which a given class was loaded, to make it easy for users to pass
* their JARs to SparkContext.
*/
def jarOfClass(cls: Class[_]): Option[String] = {
val uri = cls.getResource("/" + cls.getName.replace('.', '/') + ".class")
if (uri != null) {
val uriStr = uri.toString
if (uriStr.startsWith("jar:file:")) {
// URI will be of the form "jar:file:/path/foo.jar!/package/cls.class",
// so pull out the /path/foo.jar
Some(uriStr.substring("jar:file:".length, uriStr.indexOf('!')))
} else {
None
}
} else {
None
}
}
/**
* Find the JAR that contains the class of a particular object, to make it easy for users
* to pass their JARs to SparkContext. In most cases you can call jarOfObject(this) in
* your driver program.
*/
def jarOfObject(obj: AnyRef): Option[String] = jarOfClass(obj.getClass)
/**
* Creates a modified version of a SparkConf with the parameters that can be passed separately
* to SparkContext, to make it easier to write SparkContext's constructors. This ignores
* parameters that are passed as the default value of null, instead of throwing an exception
* like SparkConf would.
*/
private[spark] def updatedConf(
conf: SparkConf,
master: String,
appName: String,
sparkHome: String = null,
jars: Seq[String] = Nil,
environment: Map[String, String] = Map()): SparkConf =
{
val res = conf.clone()
res.setMaster(master)
res.setAppName(appName)
if (sparkHome != null) {
res.setSparkHome(sparkHome)
}
if (jars != null && !jars.isEmpty) {
res.setJars(jars)
}
res.setExecutorEnv(environment.toSeq)
res
}
/**
* The number of driver cores to use for execution in local mode, 0 otherwise.
*/
private[spark] def numDriverCores(master: String): Int = {
def convertToInt(threads: String): Int = {
if (threads == "*") Runtime.getRuntime.availableProcessors() else threads.toInt
}
master match {
case "local" => 1
case SparkMasterRegex.LOCAL_N_REGEX(threads) => convertToInt(threads)
case SparkMasterRegex.LOCAL_N_FAILURES_REGEX(threads, _) => convertToInt(threads)
case _ => 0 // driver is not used for execution
}
}
/**
* Create a task scheduler based on a given master URL.
* Return a 2-tuple of the scheduler backend and the task scheduler.
*/
private def createTaskScheduler(
sc: SparkContext,
master: String,
deployMode: String): (SchedulerBackend, TaskScheduler) = {
import SparkMasterRegex._
// When running locally, don't try to re-execute tasks on failure.
val MAX_LOCAL_TASK_FAILURES = 1
master match {
case "local" =>
val scheduler = new TaskSchedulerImpl(sc, MAX_LOCAL_TASK_FAILURES, isLocal = true)
val backend = new LocalSchedulerBackend(sc.getConf, scheduler, 1)
scheduler.initialize(backend)
(backend, scheduler)
case LOCAL_N_REGEX(threads) =>
def localCpuCount: Int = Runtime.getRuntime.availableProcessors()
// local[*] estimates the number of cores on the machine; local[N] uses exactly N threads.
val threadCount = if (threads == "*") localCpuCount else threads.toInt
if (threadCount <= 0) {
throw new SparkException(s"Asked to run locally with $threadCount threads")
}
val scheduler = new TaskSchedulerImpl(sc, MAX_LOCAL_TASK_FAILURES, isLocal = true)
val backend = new LocalSchedulerBackend(sc.getConf, scheduler, threadCount)
scheduler.initialize(backend)
(backend, scheduler)
case LOCAL_N_FAILURES_REGEX(threads, maxFailures) =>
def localCpuCount: Int = Runtime.getRuntime.availableProcessors()
// local[*, M] means the number of cores on the computer with M failures
// local[N, M] means exactly N threads with M failures
val threadCount = if (threads == "*") localCpuCount else threads.toInt
val scheduler = new TaskSchedulerImpl(sc, maxFailures.toInt, isLocal = true)
val backend = new LocalSchedulerBackend(sc.getConf, scheduler, threadCount)
scheduler.initialize(backend)
(backend, scheduler)
case SPARK_REGEX(sparkUrl) =>
val scheduler = new TaskSchedulerImpl(sc)
val masterUrls = sparkUrl.split(",").map("spark://" + _)
val backend = new StandaloneSchedulerBackend(scheduler, sc, masterUrls)
scheduler.initialize(backend)
(backend, scheduler)
case LOCAL_CLUSTER_REGEX(numSlaves, coresPerSlave, memoryPerSlave) =>
// Check to make sure memory requested <= memoryPerSlave. Otherwise Spark will just hang.
val memoryPerSlaveInt = memoryPerSlave.toInt
if (sc.executorMemory > memoryPerSlaveInt) {
throw new SparkException(
"Asked to launch cluster with %d MB RAM / worker but requested %d MB/worker".format(
memoryPerSlaveInt, sc.executorMemory))
}
val scheduler = new TaskSchedulerImpl(sc)
val localCluster = new LocalSparkCluster(
numSlaves.toInt, coresPerSlave.toInt, memoryPerSlaveInt, sc.conf)
val masterUrls = localCluster.start()
val backend = new StandaloneSchedulerBackend(scheduler, sc, masterUrls)
scheduler.initialize(backend)
backend.shutdownCallback = (backend: StandaloneSchedulerBackend) => {
localCluster.stop()
}
(backend, scheduler)
case masterUrl =>
val cm = getClusterManager(masterUrl) match {
case Some(clusterMgr) => clusterMgr
case None => throw new SparkException("Could not parse Master URL: '" + master + "'")
}
try {
val scheduler = cm.createTaskScheduler(sc, masterUrl)
val backend = cm.createSchedulerBackend(sc, masterUrl, scheduler)
cm.initialize(scheduler, backend)
(backend, scheduler)
} catch {
case se: SparkException => throw se
case NonFatal(e) =>
throw new SparkException("External scheduler cannot be instantiated", e)
}
}
}
private def getClusterManager(url: String): Option[ExternalClusterManager] = {
val loader = Utils.getContextOrSparkClassLoader
val serviceLoaders =
ServiceLoader.load(classOf[ExternalClusterManager], loader).asScala.filter(_.canCreate(url))
if (serviceLoaders.size > 1) {
throw new SparkException(
s"Multiple external cluster managers registered for the url $url: $serviceLoaders")
}
serviceLoaders.headOption
}
}
/**
* A collection of regexes for extracting information from the master string.
*/
private object SparkMasterRegex {
// Regular expression used for local[N] and local[*] master formats
val LOCAL_N_REGEX = """local\[([0-9]+|\*)\]""".r
// Regular expression for local[N, maxRetries], used in tests with failing tasks
val LOCAL_N_FAILURES_REGEX = """local\[([0-9]+|\*)\s*,\s*([0-9]+)\]""".r
// Regular expression for simulating a Spark cluster of [N, cores, memory] locally
val LOCAL_CLUSTER_REGEX = """local-cluster\[\s*([0-9]+)\s*,\s*([0-9]+)\s*,\s*([0-9]+)\s*]""".r
// Regular expression for connecting to Spark deploy clusters
val SPARK_REGEX = """spark://(.*)""".r
}
/**
* A class encapsulating how to convert some type T to Writable. It stores both the Writable class
* corresponding to T (e.g. IntWritable for Int) and a function for doing the conversion.
* The getter for the writable class takes a ClassTag[T] in case this is a generic object
* that doesn't know the type of T when it is created. This sounds strange but is necessary to
* support converting subclasses of Writable to themselves (writableWritableConverter).
*/
private[spark] class WritableConverter[T](
val writableClass: ClassTag[T] => Class[_ <: Writable],
val convert: Writable => T)
extends Serializable
object WritableConverter {
// Helper objects for converting common types to Writable
private[spark] def simpleWritableConverter[T, W <: Writable: ClassTag](convert: W => T)
: WritableConverter[T] = {
val wClass = classTag[W].runtimeClass.asInstanceOf[Class[W]]
new WritableConverter[T](_ => wClass, x => convert(x.asInstanceOf[W]))
}
// The following implicit functions were in SparkContext before 1.3 and users had to
// `import SparkContext._` to enable them. Now we move them here to make the compiler find
// them automatically. However, we still keep the old functions in SparkContext for backward
// compatibility and forward to the following functions directly.
implicit def intWritableConverter(): WritableConverter[Int] =
simpleWritableConverter[Int, IntWritable](_.get)
implicit def longWritableConverter(): WritableConverter[Long] =
simpleWritableConverter[Long, LongWritable](_.get)
implicit def doubleWritableConverter(): WritableConverter[Double] =
simpleWritableConverter[Double, DoubleWritable](_.get)
implicit def floatWritableConverter(): WritableConverter[Float] =
simpleWritableConverter[Float, FloatWritable](_.get)
implicit def booleanWritableConverter(): WritableConverter[Boolean] =
simpleWritableConverter[Boolean, BooleanWritable](_.get)
implicit def bytesWritableConverter(): WritableConverter[Array[Byte]] = {
simpleWritableConverter[Array[Byte], BytesWritable] { bw =>
// getBytes method returns array which is longer then data to be returned
Arrays.copyOfRange(bw.getBytes, 0, bw.getLength)
}
}
implicit def stringWritableConverter(): WritableConverter[String] =
simpleWritableConverter[String, Text](_.toString)
implicit def writableWritableConverter[T <: Writable](): WritableConverter[T] =
new WritableConverter[T](_.runtimeClass.asInstanceOf[Class[T]], _.asInstanceOf[T])
}
/**
* A class encapsulating how to convert some type T to Writable. It stores both the Writable class
* corresponding to T (e.g. IntWritable for Int) and a function for doing the conversion.
* The Writable class will be used in `SequenceFileRDDFunctions`.
*/
private[spark] class WritableFactory[T](
val writableClass: ClassTag[T] => Class[_ <: Writable],
val convert: T => Writable) extends Serializable
object WritableFactory {
private[spark] def simpleWritableFactory[T: ClassTag, W <: Writable : ClassTag](convert: T => W)
: WritableFactory[T] = {
val writableClass = implicitly[ClassTag[W]].runtimeClass.asInstanceOf[Class[W]]
new WritableFactory[T](_ => writableClass, convert)
}
implicit def intWritableFactory: WritableFactory[Int] =
simpleWritableFactory(new IntWritable(_))
implicit def longWritableFactory: WritableFactory[Long] =
simpleWritableFactory(new LongWritable(_))
implicit def floatWritableFactory: WritableFactory[Float] =
simpleWritableFactory(new FloatWritable(_))
implicit def doubleWritableFactory: WritableFactory[Double] =
simpleWritableFactory(new DoubleWritable(_))
implicit def booleanWritableFactory: WritableFactory[Boolean] =
simpleWritableFactory(new BooleanWritable(_))
implicit def bytesWritableFactory: WritableFactory[Array[Byte]] =
simpleWritableFactory(new BytesWritable(_))
implicit def stringWritableFactory: WritableFactory[String] =
simpleWritableFactory(new Text(_))
implicit def writableWritableFactory[T <: Writable: ClassTag]: WritableFactory[T] =
simpleWritableFactory(w => w)
}