I wanted to build this simple Spark Streaming application that monitors a particular directory in HDFS and whenever a new file shows up, i want to print its content to Console.
I built this HDFSFileStream.scala. In this program after creating a SparkStreamContext. I am calling
sparkStreamingContext.textFileStream(<directoryName>)
on it. Once a new file appears in the directory the value of fileRDD.count() would return more than 0 and then i invoke
processNewFile()
. The
processNewFile()
method takes a RDD[String], iterates through the file content and prints it to console
Next start the program by executing following code
bin/spark-submit ~/HelloSparkStreaming-1.0-SNAPSHOT-jar-with-dependencies.jar /user/mapr/stream 3
Once the streaming started it starts monitoring
/user/mapr/stream
directory, for new content. I copied a file with few lines in it and i got the following output, which is content of the file
5 comments:
Hello Sunil,
Thanks for the blog. I need to implement similar code for a component of mine. Had a couple of questions ? I mean
1. I was wondering what kind of load will your approach place on the hdfs namenode. Will you be constantly pinging the namenode to get the latest files on your monitored directories ? Is this going to cause any adverse performance issues on the cluster?
2. Is there a push model instead of this pull model so that your code can be notified of the existence of a new file in hdfs ; rather than querying hdfs ourselves ?
Thanks !
Basanth
Hi Sunil
I would like to refer HDFSFileStream.scala.
I have below requirement
I need to monitor few directories in our cluster and make report every month for below things;
Size of the directories previous month and current month
Monitor new folders which are getting added in current month.
create this report every month
can i get the above code for pyspark?
Thanks for info....
Website development in Bangalore
very nice article,Thank you ..
Keep updating..
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