spark MiniReadWriteTest 源码

spark MiniReadWriteTest 代码

文件路径：/examples/src/main/scala/org/apache/spark/examples/MiniReadWriteTest.scala

/*
 * 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.
 */

// scalastyle:off println
package org.apache.spark.examples

import java.io.File
import java.io.PrintWriter

import scala.io.Source._

import org.apache.spark.sql.SparkSession
import org.apache.spark.util.Utils

/**
 * Simple test for reading and writing to a distributed
 * file system.  This example does the following:
 *
 *   1. Reads local file
 *   2. Computes word count on local file
 *   3. Writes local file to a local dir on each executor
 *   4. Reads the file back from each exec
 *   5. Computes word count on the file using Spark
 *   6. Compares the word count results
 */
object MiniReadWriteTest {

  private val NPARAMS = 1

  private def readFile(filename: String): List[String] = {
    Utils.tryWithResource(fromFile(filename))(_.getLines().toList)
  }

  private def printUsage(): Unit = {
    val usage = """Mini Read-Write Test
    |Usage: localFile
    |localFile - (string) location of local file to distribute to executors.""".stripMargin

    println(usage)
  }

  private def parseArgs(args: Array[String]): File = {
    if (args.length != NPARAMS) {
      printUsage()
      System.exit(1)
    }

    val filePath = args(0)

    val localFilePath = new File(filePath)
    if (!localFilePath.exists) {
      System.err.println(s"Given path ($filePath) does not exist")
      printUsage()
      System.exit(1)
    }

    if (!localFilePath.isFile) {
      System.err.println(s"Given path ($filePath) is not a file")
      printUsage()
      System.exit(1)
    }
    localFilePath
  }

  def runLocalWordCount(fileContents: List[String]): Int = {
    fileContents.flatMap(_.split(" "))
      .flatMap(_.split("\t"))
      .filter(_.nonEmpty)
      .groupBy(w => w)
      .mapValues(_.size)
      .values
      .sum
  }

  def main(args: Array[String]): Unit = {
    val localFilePath = parseArgs(args)

    println(s"Performing local word count from ${localFilePath}")
    val fileContents = readFile(localFilePath.toString())
    println(s"File contents are ${fileContents}")
    val localWordCount = runLocalWordCount(fileContents)

    println("Creating SparkSession")
    val spark = SparkSession
      .builder
      .appName("Mini Read Write Test")
      .getOrCreate()

    println("Writing local file to executors")

    // uses the fact default parallelism is greater than num execs
    val misc = spark.sparkContext.parallelize(1.to(10))
    misc.foreachPartition {
      x =>
        new PrintWriter(localFilePath) {
          try {
            write(fileContents.mkString("\n"))
          } finally {
            close()
          }}
    }

    println("Reading file from execs and running Word Count")
    val readFileRDD = spark.sparkContext.textFile(localFilePath.toString())

    val dWordCount = readFileRDD
      .flatMap(_.split(" "))
      .flatMap(_.split("\t"))
      .filter(_.nonEmpty)
      .map(w => (w, 1))
      .countByKey()
      .values
      .sum

    spark.stop()
    if (localWordCount == dWordCount) {
      println(s"Success! Local Word Count $localWordCount and " +
        s"D Word Count $dWordCount agree.")
    } else {
      println(s"Failure! Local Word Count $localWordCount " +
        s"and D Word Count $dWordCount disagree.")
    }
  }
}
// scalastyle:on println

相关信息

spark 源码目录

相关文章

spark AccumulatorMetricsTest 源码

spark BroadcastTest 源码

spark DFSReadWriteTest 源码

spark DriverSubmissionTest 源码

spark ExceptionHandlingTest 源码

spark GroupByTest 源码

spark HdfsTest 源码

spark LocalALS 源码

spark LocalFileLR 源码

spark LocalKMeans 源码