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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.streaming.util
import org.apache.spark.Logging
import org.apache.spark.rdd.RDD
import org.apache.spark.streaming._
import org.apache.spark.streaming.dstream.{DStream, ForEachDStream}
import org.apache.spark.util.Utils
import StreamingContext._
import scala.util.Random
import scala.collection.mutable.{SynchronizedBuffer, ArrayBuffer}
import scala.reflect.ClassTag
import java.io.{File, ObjectInputStream, IOException}
import java.nio.charset.Charset
import java.util.UUID
import com.google.common.io.Files
import org.apache.hadoop.fs.Path
import org.apache.hadoop.conf.Configuration
private[streaming]
object MasterFailureTest extends Logging {
@volatile var killed = false
@volatile var killCount = 0
@volatile var setupCalled = false
def main(args: Array[String]) {
if (args.size < 2) {
println(
"Usage: MasterFailureTest <local/HDFS directory> <# batches> " +
"[<batch size in milliseconds>]")
System.exit(1)
}
val directory = args(0)
val numBatches = args(1).toInt
val batchDuration = if (args.size > 2) Milliseconds(args(2).toInt) else Seconds(1)
println("\n\n========================= MAP TEST =========================\n\n")
testMap(directory, numBatches, batchDuration)
println("\n\n================= UPDATE-STATE-BY-KEY TEST =================\n\n")
testUpdateStateByKey(directory, numBatches, batchDuration)
println("\n\nSUCCESS\n\n")
}
def testMap(directory: String, numBatches: Int, batchDuration: Duration) {
// Input: time=1 ==> [ 1 ] , time=2 ==> [ 2 ] , time=3 ==> [ 3 ] , ...
val input = (1 to numBatches).map(_.toString).toSeq
// Expected output: time=1 ==> [ 1 ] , time=2 ==> [ 2 ] , time=3 ==> [ 3 ] , ...
val expectedOutput = (1 to numBatches)
val operation = (st: DStream[String]) => st.map(_.toInt)
// Run streaming operation with multiple master failures
val output = testOperation(directory, batchDuration, input, operation, expectedOutput)
logInfo("Expected output, size = " + expectedOutput.size)
logInfo(expectedOutput.mkString("[", ",", "]"))
logInfo("Output, size = " + output.size)
logInfo(output.mkString("[", ",", "]"))
// Verify whether all the values of the expected output is present
// in the output
assert(output.distinct.toSet == expectedOutput.toSet)
}
def testUpdateStateByKey(directory: String, numBatches: Int, batchDuration: Duration) {
// Input: time=1 ==> [ a ] , time=2 ==> [ a, a ] , time=3 ==> [ a, a, a ] , ...
val input = (1 to numBatches).map(i => (1 to i).map(_ => "a").mkString(" ")).toSeq
// Expected output: time=1 ==> [ (a, 1) ] , time=2 ==> [ (a, 3) ] , time=3 ==> [ (a,6) ] , ...
val expectedOutput = (1L to numBatches).map(i => (1L to i).reduce(_ + _)).map(j => ("a", j))
val operation = (st: DStream[String]) => {
val updateFunc = (values: Seq[Long], state: Option[Long]) => {
Some(values.foldLeft(0L)(_ + _) + state.getOrElse(0L))
}
st.flatMap(_.split(" "))
.map(x => (x, 1L))
.updateStateByKey[Long](updateFunc)
.checkpoint(batchDuration * 5)
}
// Run streaming operation with multiple master failures
val output = testOperation(directory, batchDuration, input, operation, expectedOutput)
logInfo("Expected output, size = " + expectedOutput.size + "\n" + expectedOutput)
logInfo("Output, size = " + output.size + "\n" + output)
// Verify whether all the values in the output are among the expected output values
output.foreach(o =>
assert(expectedOutput.contains(o), "Expected value " + o + " not found")
)
// Verify whether the last expected output value has been generated, there by
// confirming that none of the inputs have been missed
assert(output.last == expectedOutput.last)
}
/**
* Tests stream operation with multiple master failures, and verifies whether the
* final set of output values is as expected or not.
*/
def testOperation[T: ClassTag](
directory: String,
batchDuration: Duration,
input: Seq[String],
operation: DStream[String] => DStream[T],
expectedOutput: Seq[T]
): Seq[T] = {
// Just making sure that the expected output does not have duplicates
assert(expectedOutput.distinct.toSet == expectedOutput.toSet)
// Reset all state
reset()
// Create the directories for this test
val uuid = UUID.randomUUID().toString
val rootDir = new Path(directory, uuid)
val fs = rootDir.getFileSystem(new Configuration())
val checkpointDir = new Path(rootDir, "checkpoint")
val testDir = new Path(rootDir, "test")
fs.mkdirs(checkpointDir)
fs.mkdirs(testDir)
// Setup the stream computation with the given operation
val ssc = StreamingContext.getOrCreate(checkpointDir.toString, () => {
setupStreams(batchDuration, operation, checkpointDir, testDir)
})
// Check if setupStream was called to create StreamingContext
// (and not created from checkpoint file)
assert(setupCalled, "Setup was not called in the first call to StreamingContext.getOrCreate")
// Start generating files in the a different thread
val fileGeneratingThread = new FileGeneratingThread(input, testDir, batchDuration.milliseconds)
fileGeneratingThread.start()
// Run the streams and repeatedly kill it until the last expected output
// has been generated, or until it has run for twice the expected time
val lastExpectedOutput = expectedOutput.last
val maxTimeToRun = expectedOutput.size * batchDuration.milliseconds * 2
val mergedOutput = runStreams(ssc, lastExpectedOutput, maxTimeToRun)
fileGeneratingThread.join()
fs.delete(checkpointDir, true)
fs.delete(testDir, true)
logInfo("Finished test after " + killCount + " failures")
mergedOutput
}
/**
* Sets up the stream computation with the given operation, directory (local or HDFS),
* and batch duration. Returns the streaming context and the directory to which
* files should be written for testing.
*/
private def setupStreams[T: ClassTag](
batchDuration: Duration,
operation: DStream[String] => DStream[T],
checkpointDir: Path,
testDir: Path
): StreamingContext = {
// Mark that setup was called
setupCalled = true
// Setup the streaming computation with the given operation
val ssc = new StreamingContext("local[4]", "MasterFailureTest", batchDuration, null, Nil,
Map())
ssc.checkpoint(checkpointDir.toString)
val inputStream = ssc.textFileStream(testDir.toString)
val operatedStream = operation(inputStream)
val outputStream = new TestOutputStream(operatedStream)
outputStream.register()
ssc
}
/**
* Repeatedly starts and kills the streaming context until timed out or
* the last expected output is generated. Finally, return
*/
private def runStreams[T: ClassTag](
ssc_ : StreamingContext,
lastExpectedOutput: T,
maxTimeToRun: Long
): Seq[T] = {
var ssc = ssc_
var totalTimeRan = 0L
var isLastOutputGenerated = false
var isTimedOut = false
val mergedOutput = new ArrayBuffer[T]()
val checkpointDir = ssc.checkpointDir
val batchDuration = ssc.graph.batchDuration
while(!isLastOutputGenerated && !isTimedOut) {
// Get the output buffer
val outputBuffer = ssc.graph.getOutputStreams.head.asInstanceOf[TestOutputStream[T]].output
def output = outputBuffer.flatMap(x => x)
// Start the thread to kill the streaming after some time
killed = false
val killingThread = new KillingThread(ssc, batchDuration.milliseconds * 10)
killingThread.start()
var timeRan = 0L
try {
// Start the streaming computation and let it run while ...
// (i) StreamingContext has not been shut down yet
// (ii) The last expected output has not been generated yet
// (iii) Its not timed out yet
System.clearProperty("spark.streaming.clock")
System.clearProperty("spark.driver.port")
ssc.start()
val startTime = System.currentTimeMillis()
while (!killed && !isLastOutputGenerated && !isTimedOut) {
Thread.sleep(100)
timeRan = System.currentTimeMillis() - startTime
isLastOutputGenerated = (!output.isEmpty && output.last == lastExpectedOutput)
isTimedOut = (timeRan + totalTimeRan > maxTimeToRun)
}
} catch {
case e: Exception => logError("Error running streaming context", e)
}
if (killingThread.isAlive) killingThread.interrupt()
ssc.stop()
logInfo("Has been killed = " + killed)
logInfo("Is last output generated = " + isLastOutputGenerated)
logInfo("Is timed out = " + isTimedOut)
// Verify whether the output of each batch has only one element or no element
// and then merge the new output with all the earlier output
mergedOutput ++= output
totalTimeRan += timeRan
logInfo("New output = " + output)
logInfo("Merged output = " + mergedOutput)
logInfo("Time ran = " + timeRan)
logInfo("Total time ran = " + totalTimeRan)
if (!isLastOutputGenerated && !isTimedOut) {
val sleepTime = Random.nextInt(batchDuration.milliseconds.toInt * 10)
logInfo(
"\n-------------------------------------------\n" +
" Restarting stream computation in " + sleepTime + " ms " +
"\n-------------------------------------------\n"
)
Thread.sleep(sleepTime)
// Recreate the streaming context from checkpoint
ssc = StreamingContext.getOrCreate(checkpointDir, () => {
throw new Exception("Trying to create new context when it " +
"should be reading from checkpoint file")
})
}
}
mergedOutput
}
/**
* Verifies the output value are the same as expected. Since failures can lead to
* a batch being processed twice, a batches output may appear more than once
* consecutively. To avoid getting confused with those, we eliminate consecutive
* duplicate batch outputs of values from the `output`. As a result, the
* expected output should not have consecutive batches with the same values as output.
*/
private def verifyOutput[T: ClassTag](output: Seq[T], expectedOutput: Seq[T]) {
// Verify whether expected outputs do not consecutive batches with same output
for (i <- 0 until expectedOutput.size - 1) {
assert(expectedOutput(i) != expectedOutput(i + 1),
"Expected output has consecutive duplicate sequence of values")
}
// Log the output
println("Expected output, size = " + expectedOutput.size)
println(expectedOutput.mkString("[", ",", "]"))
println("Output, size = " + output.size)
println(output.mkString("[", ",", "]"))
// Match the output with the expected output
output.foreach(o =>
assert(expectedOutput.contains(o), "Expected value " + o + " not found")
)
}
/** Resets counter to prepare for the test */
private def reset() {
killed = false
killCount = 0
setupCalled = false
}
}
/**
* This is a output stream just for testing. All the output is collected into a
* ArrayBuffer. This buffer is wiped clean on being restored from checkpoint.
*/
private[streaming]
class TestOutputStream[T: ClassTag](
parent: DStream[T],
val output: ArrayBuffer[Seq[T]] = new ArrayBuffer[Seq[T]] with SynchronizedBuffer[Seq[T]]
) extends ForEachDStream[T](
parent,
(rdd: RDD[T], t: Time) => {
val collected = rdd.collect()
output += collected
}
) {
// This is to clear the output buffer every it is read from a checkpoint
@throws(classOf[IOException])
private def readObject(ois: ObjectInputStream) {
ois.defaultReadObject()
output.clear()
}
}
/**
* Thread to kill streaming context after a random period of time.
*/
private[streaming]
class KillingThread(ssc: StreamingContext, maxKillWaitTime: Long) extends Thread with Logging {
override def run() {
try {
// If it is the first killing, then allow the first checkpoint to be created
var minKillWaitTime = if (MasterFailureTest.killCount == 0) 5000 else 2000
val killWaitTime = minKillWaitTime + math.abs(Random.nextLong % maxKillWaitTime)
logInfo("Kill wait time = " + killWaitTime)
Thread.sleep(killWaitTime)
logInfo(
"\n---------------------------------------\n" +
"Killing streaming context after " + killWaitTime + " ms" +
"\n---------------------------------------\n"
)
if (ssc != null) {
ssc.stop()
MasterFailureTest.killed = true
MasterFailureTest.killCount += 1
}
logInfo("Killing thread finished normally")
} catch {
case ie: InterruptedException => logInfo("Killing thread interrupted")
case e: Exception => logWarning("Exception in killing thread", e)
}
}
}
/**
* Thread to generate input files periodically with the desired text.
*/
private[streaming]
class FileGeneratingThread(input: Seq[String], testDir: Path, interval: Long)
extends Thread with Logging {
override def run() {
val localTestDir = Files.createTempDir()
localTestDir.deleteOnExit()
var fs = testDir.getFileSystem(new Configuration())
val maxTries = 3
try {
Thread.sleep(5000) // To make sure that all the streaming context has been set up
for (i <- 0 until input.size) {
// Write the data to a local file and then move it to the target test directory
val localFile = new File(localTestDir, (i + 1).toString)
val hadoopFile = new Path(testDir, (i + 1).toString)
val tempHadoopFile = new Path(testDir, ".tmp_" + (i + 1).toString)
Files.write(input(i) + "\n", localFile, Charset.forName("UTF-8"))
var tries = 0
var done = false
while (!done && tries < maxTries) {
tries += 1
try {
// fs.copyFromLocalFile(new Path(localFile.toString), hadoopFile)
fs.copyFromLocalFile(new Path(localFile.toString), tempHadoopFile)
fs.rename(tempHadoopFile, hadoopFile)
done = true
} catch {
case ioe: IOException => {
fs = testDir.getFileSystem(new Configuration())
logWarning("Attempt " + tries + " at generating file " + hadoopFile + " failed.",
ioe)
}
}
}
if (!done) {
logError("Could not generate file " + hadoopFile)
} else {
logInfo("Generated file " + hadoopFile + " at " + System.currentTimeMillis)
}
Thread.sleep(interval)
localFile.delete()
}
logInfo("File generating thread finished normally")
} catch {
case ie: InterruptedException => logInfo("File generating thread interrupted")
case e: Exception => logWarning("File generating in killing thread", e)
} finally {
fs.close()
Utils.deleteRecursively(localTestDir)
}
}
}
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