This is a simple python script for counting words and characters from a text file in Spark.
I have used Spark from the Cloudera Quickstart VM for VirtualBox which you can download from here. Download and import the .ovf file in VirtualBox and once the setup is done, you can use Spark from the terminal using the following command.
pyspark
I have kept the input text file(input_textfile.txt) at HDFS in the directory /user/root/.
To keep your file in HDFS, you can do the following.
If you do not have the "root" directory in HDFS, create it using the following command
sudo -u hdfs hadoop fs -mkdir /user/root
Then copy your local file in the HDFS directory. For example, if you have the input file "input_textfile.txt" in Documents directory, you can copy it to HDFS using the following command.
hadoop fs -copyFromLocal Documents/input_textfile.txt hdfs://localhost/user/root/input_textfile.txt
Once you are done with copying the file to HDFS, you can run the script "word_count.py" from it's directory. Mind it, it's not a normal python script to execute so "python word_count.py" will not work from the terminal, you have to use spark commands to execute that.
Run the script using the following command:
spark-submit --master yarn --deploy-mode client --executor-memory 1g --name wordcount --conf "spark.app.id=wordcount" word_count.py
If everything goes well, you will get 3(Three) files "output.txt"(for both the word and character counts in text format), "word_output.csv"(for the word counts in CSV format) and "char_output.csv"(for the character counts in CSV format) in the same directory where "word_count.py" is.
And you are DONE!! Voila!!