Hi guys i have the next problem. I'm using Apache Spark Streaming v1.6.0 with Java to have some messages from IBM MQ. I made my custom receiver for MQ but the problem that i have is that i need to convert the RDD from JavaDStream to DataFrame. For that i iterate the JavaDStream with the foreachRDD and i defined the schema for the DataFrame but when i run the job, the firsts messages tthrow the next exception:
java.lang.ClassCastException: org.apache.spark.rdd.BlockRDDPartition cannot be cast to org.apache.spark.rdd.ParallelCollectionPartition at org.apache.spark.rdd.ParallelCollectionRDD.compute(ParallelCollectionRDD.scala:102) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306) at org.apache.spark.rdd.RDD.iterator(RDD.scala:270) at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:66) at org.apache.spark.scheduler.Task.run(Task.scala:89) at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:213) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) 19/03/28 12:53:26 WARN TaskSetManager: Lost task 0.0 in stage 0.0 (TID 0, localhost): java.lang.ClassCastException: org.apache.spark.rdd.BlockRDDPartition cannot be cast to org.apache.spark.rdd.ParallelCollectionPartition at org.apache.spark.rdd.ParallelCollectionRDD.compute(ParallelCollectionRDD.scala:102) at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306) at org.apache.spark.rdd.RDD.iterator(RDD.scala:270) at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:66) at org.apache.spark.scheduler.Task.run(Task.scala:89) at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:213) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)
Then the code executes very well. Even if i dont have any messages in MQ, is just the first messages when i run de the job.
Here is my CustomMQReceiver
public CustomMQReceiver() {
super(StorageLevel.MEMORY_ONLY_2());
}
@Override
public void onStart() {
new Thread() {
@Override
public void run() {
try {
initConnection();
receive();
} catch (JMSException ex) {
ex.printStackTrace();
}
}
}.start();
}
@Override
public void onStop() {
}
private void receive() {
System.out.print("Started receiving messages from MQ");
try {
Message receivedMessage = null;
while (!isStopped() && (receivedMessage = consumer.receiveNoWait()) != null) {
String userInput = convertStreamToString(receivedMessage);
System.out.println("Received data :'" + userInput + "'");
store(userInput);
}
stop("No More Messages To read !");
qCon.close();
System.out.println("Queue Connection is Closed");
} catch (Exception e) {
e.printStackTrace();
restart("Trying to connect again");
} catch (Throwable t) {
restart("Error receiving data", t);
}
}
public void initConnection() throws JMSException {
MQQueueConnectionFactory conFactory = new MQQueueConnectionFactory();
conFactory.setHostName(HOST);
conFactory.setPort(PORT);
conFactory.setIntProperty(WMQConstants.WMQ_CONNECTION_MODE, WMQConstants.WMQ_CM_CLIENT);
conFactory.setQueueManager(QMGR);
conFactory.setChannel(CHANNEL);
conFactory.setBooleanProperty(WMQConstants.USER_AUTHENTICATION_MQCSP, true);
conFactory.setStringProperty(WMQConstants.USERID, APP_USER);
conFactory.setStringProperty(WMQConstants.PASSWORD, APP_PASSWORD);
qCon = (MQQueueConnection) conFactory.createConnection();
MQQueueSession qSession = (MQQueueSession) qCon.createQueueSession(false, 1);
MQQueue queue = (MQQueue) qSession.createQueue(QUEUE_NAME);
consumer = (MQMessageConsumer) qSession.createConsumer(queue);
qCon.start();
}
@Override
public StorageLevel storageLevel() {
return StorageLevel.MEMORY_ONLY_2();
}
private static String convertStreamToString(final Message jmsMsg) throws Exception {
String stringMessage = "";
JMSTextMessage msg = (JMSTextMessage) jmsMsg;
stringMessage = msg.getText();
return stringMessage;
}
And here is my code of spark
SparkConf sparkConf = new SparkConf()
.setAppName("MQStreaming")
.set("spark.driver.allowMultipleContexts", "true")
.setMaster("local[*]");
JavaSparkContext jsc = new JavaSparkContext(sparkConf);
final SQLContext sqlContext = new SQLContext(jsc);
JavaStreamingContext ssc = new JavaStreamingContext(sparkConf, new Duration(Long.parseLong(propertiesConf.getProperty("duration"))));
JavaDStream<String> customReceiverStream = ssc.receiverStream(new CustomMQReceiver());
customReceiverStream.foreachRDD(new VoidFunction<JavaRDD<String>>() {
@Override
public void call(JavaRDD<String> rdd) throws Exception {
JavaRDD<Row> rddRow = rdd.map(new Function<String, Row>() {
@Override
public Row call(String v1) throws Exception {
return RowFactory.create(v1);
}
});
try {
StructType schema = new StructType(new StructField[]{
new StructField("trama", DataTypes.StringType, true, Metadata.empty())
});
DataFrame frame = sqlContext.createDataFrame(rddRow, schema);
if (frame.count() > 0) {
//Here is where the first messages throw the exception
frame.show();
frame.write().mode(SaveMode.Append).json("file:///C:/tmp/");
}
} catch (Exception ex) {
System.out.println(" INFO " + ex.getMessage());
}
}
});
ssc.start();
ssc.awaitTermination();
I can't change the version of spark because this job will run in a old cloudera cluster with spark 1.6. I don't know if i'm doing something wrong or is a just a bug. Help!!!!
