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Diffstat (limited to 'examples/src/main/scala')
-rw-r--r-- | examples/src/main/scala/org/apache/spark/examples/streaming/SqlNetworkWordCount.scala | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/examples/src/main/scala/org/apache/spark/examples/streaming/SqlNetworkWordCount.scala b/examples/src/main/scala/org/apache/spark/examples/streaming/SqlNetworkWordCount.scala new file mode 100644 index 0000000000..5a6b9216a3 --- /dev/null +++ b/examples/src/main/scala/org/apache/spark/examples/streaming/SqlNetworkWordCount.scala @@ -0,0 +1,101 @@ +/* + * 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.examples.streaming + +import org.apache.spark.SparkConf +import org.apache.spark.SparkContext +import org.apache.spark.rdd.RDD +import org.apache.spark.streaming.{Time, Seconds, StreamingContext} +import org.apache.spark.util.IntParam +import org.apache.spark.sql.SQLContext +import org.apache.spark.storage.StorageLevel + +/** + * Use DataFrames and SQL to count words in UTF8 encoded, '\n' delimited text received from the + * network every second. + * + * Usage: SqlNetworkWordCount <hostname> <port> + * <hostname> and <port> describe the TCP server that Spark Streaming would connect to receive data. + * + * To run this on your local machine, you need to first run a Netcat server + * `$ nc -lk 9999` + * and then run the example + * `$ bin/run-example org.apache.spark.examples.streaming.SqlNetworkWordCount localhost 9999` + */ + +object SqlNetworkWordCount { + def main(args: Array[String]) { + if (args.length < 2) { + System.err.println("Usage: NetworkWordCount <hostname> <port>") + System.exit(1) + } + + StreamingExamples.setStreamingLogLevels() + + // Create the context with a 2 second batch size + val sparkConf = new SparkConf().setAppName("SqlNetworkWordCount") + val ssc = new StreamingContext(sparkConf, Seconds(2)) + + // Create a socket stream on target ip:port and count the + // words in input stream of \n delimited text (eg. generated by 'nc') + // Note that no duplication in storage level only for running locally. + // Replication necessary in distributed scenario for fault tolerance. + val lines = ssc.socketTextStream(args(0), args(1).toInt, StorageLevel.MEMORY_AND_DISK_SER) + val words = lines.flatMap(_.split(" ")) + + // Convert RDDs of the words DStream to DataFrame and run SQL query + words.foreachRDD((rdd: RDD[String], time: Time) => { + // Get the singleton instance of SQLContext + val sqlContext = SQLContextSingleton.getInstance(rdd.sparkContext) + import sqlContext.implicits._ + + // Convert RDD[String] to RDD[case class] to DataFrame + val wordsDataFrame = rdd.map(w => Record(w)).toDF() + + // Register as table + wordsDataFrame.registerTempTable("words") + + // Do word count on table using SQL and print it + val wordCountsDataFrame = + sqlContext.sql("select word, count(*) as total from words group by word") + println(s"========= $time =========") + wordCountsDataFrame.show() + }) + + ssc.start() + ssc.awaitTermination() + } +} + + +/** Case class for converting RDD to DataFrame */ +case class Record(word: String) + + +/** Lazily instantiated singleton instance of SQLContext */ +object SQLContextSingleton { + + @transient private var instance: SQLContext = _ + + def getInstance(sparkContext: SparkContext): SQLContext = { + if (instance == null) { + instance = new SQLContext(sparkContext) + } + instance + } +} |