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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 spark.streaming
import util.{ManualClock, RecurringTimer, Clock}
import spark.SparkEnv
import spark.Logging
private[streaming]
class Scheduler(ssc: StreamingContext) extends Logging {
initLogging()
val concurrentJobs = System.getProperty("spark.streaming.concurrentJobs", "1").toInt
val jobManager = new JobManager(ssc, concurrentJobs)
val checkpointWriter = if (ssc.checkpointDuration != null && ssc.checkpointDir != null) {
new CheckpointWriter(ssc.checkpointDir)
} else {
null
}
val clockClass = System.getProperty("spark.streaming.clock", "spark.streaming.util.SystemClock")
val clock = Class.forName(clockClass).newInstance().asInstanceOf[Clock]
val timer = new RecurringTimer(clock, ssc.graph.batchDuration.milliseconds,
longTime => generateJobs(new Time(longTime)))
val graph = ssc.graph
var latestTime: Time = null
def start() = synchronized {
if (ssc.isCheckpointPresent) {
restart()
} else {
startFirstTime()
}
logInfo("Scheduler started")
}
def stop() = synchronized {
timer.stop()
jobManager.stop()
if (checkpointWriter != null) checkpointWriter.stop()
ssc.graph.stop()
logInfo("Scheduler stopped")
}
private def startFirstTime() {
val startTime = new Time(timer.getStartTime())
graph.start(startTime - graph.batchDuration)
timer.start(startTime.milliseconds)
logInfo("Scheduler's timer started at " + startTime)
}
private def restart() {
// If manual clock is being used for testing, then
// either set the manual clock to the last checkpointed time,
// or if the property is defined set it to that time
if (clock.isInstanceOf[ManualClock]) {
val lastTime = ssc.initialCheckpoint.checkpointTime.milliseconds
val jumpTime = System.getProperty("spark.streaming.manualClock.jump", "0").toLong
clock.asInstanceOf[ManualClock].setTime(lastTime + jumpTime)
}
val batchDuration = ssc.graph.batchDuration
// Batches when the master was down, that is,
// between the checkpoint and current restart time
val checkpointTime = ssc.initialCheckpoint.checkpointTime
val restartTime = new Time(timer.getRestartTime(graph.zeroTime.milliseconds))
val downTimes = checkpointTime.until(restartTime, batchDuration)
logInfo("Batches during down time: " + downTimes.mkString(", "))
// Batches that were unprocessed before failure
val pendingTimes = ssc.initialCheckpoint.pendingTimes
logInfo("Batches pending processing: " + pendingTimes.mkString(", "))
// Reschedule jobs for these times
val timesToReschedule = (pendingTimes ++ downTimes).distinct.sorted(Time.ordering)
logInfo("Batches to reschedule: " + timesToReschedule.mkString(", "))
timesToReschedule.foreach(time =>
graph.generateJobs(time).foreach(jobManager.runJob)
)
// Restart the timer
timer.start(restartTime.milliseconds)
logInfo("Scheduler's timer restarted at " + restartTime)
}
/** Generate jobs and perform checkpoint for the given `time`. */
def generateJobs(time: Time) {
SparkEnv.set(ssc.env)
logInfo("\n-----------------------------------------------------\n")
graph.generateJobs(time).foreach(jobManager.runJob)
latestTime = time
doCheckpoint(time)
}
/**
* Clear old metadata assuming jobs of `time` have finished processing.
* And also perform checkpoint.
*/
def clearOldMetadata(time: Time) {
ssc.graph.clearOldMetadata(time)
doCheckpoint(time)
}
/** Perform checkpoint for the give `time`. */
def doCheckpoint(time: Time) = synchronized {
if (ssc.checkpointDuration != null && (time - graph.zeroTime).isMultipleOf(ssc.checkpointDuration)) {
logInfo("Checkpointing graph for time " + time)
ssc.graph.updateCheckpointData(time)
checkpointWriter.write(new Checkpoint(ssc, time))
}
}
}
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