Tutorial: Create a Scala Maven application for Apache Spark in HDInsight using IntelliJ

In this tutorial, you learn how to create an Apache Spark application written in Scala using Apache Maven with IntelliJ IDEA. The article uses Apache Maven as the build system and starts with an existing Maven archetype for Scala provided by IntelliJ IDEA. Creating a Scala application in IntelliJ IDEA involves the following steps:

  • Use Maven as the build system.
  • Update Project Object Model (POM) file to resolve Spark module dependencies.
  • Write your application in Scala.
  • Generate a jar file that can be submitted to HDInsight Spark clusters.
  • Run the application on Spark cluster using Livy.

Note

HDInsight also provides an IntelliJ IDEA plugin tool to ease the process of creating and submitting applications to an HDInsight Spark cluster on Linux. For more information, see Use HDInsight Tools Plugin for IntelliJ IDEA to create and submit Apache Spark applications.

In this tutorial, you learn how to:

  • Use IntelliJ to develop a Scala Maven application

If you don't have an Azure subscription, create a free account before you begin.

Prerequisites

Install Scala plugin for IntelliJ IDEA

Perform the following steps to install the Scala plugin:

  1. Open IntelliJ IDEA.

  2. On the welcome screen, navigate to Configure > Plugins to open the Plugins window.

    Enable scala plugin

  3. Select Install for the Scala plugin that is featured in the new window.

    Install scala plugin

  4. After the plugin installs successfully, you must restart the IDE.

Use IntelliJ to create application

  1. Start IntelliJ IDEA, and select Create New Project to open the New Project window.

  2. Select Azure Spark/HDInsight from the left pane.

  3. Select Spark Project (Scala) from the main window.

  4. From the Build tool drop-down list, select one of the following:

    • Maven for Scala project-creation wizard support.
    • SBT for managing the dependencies and building for the Scala project.

    The New Project dialog box

  5. Select Next.

  6. In the New Project window, provide the following information:

    Property Description
    Project name Enter a name.
    Project location Enter the desired location to save your project.
    Project SDK This will be blank on your first use of IDEA. Select New... and navigate to your JDK.
    Spark Version The creation wizard integrates the proper version for Spark SDK and Scala SDK. If the Spark cluster version is earlier than 2.0, select Spark 1.x. Otherwise, select Spark2.x. This example uses Spark 2.3.0 (Scala 2.11.8).

    Selecting the Spark SDK

  7. Select Finish.

Create a standalone Scala project

  1. Start IntelliJ IDEA, and select Create New Project to open the New Project window.

  2. Select Maven from the left pane.

  3. Specify a Project SDK. If blank, select New... and navigate to the Java installation directory.

  4. Select the Create from archetype checkbox.

  5. From the list of archetypes, select org.scala-tools.archetypes:scala-archetype-simple. This archetype creates the right directory structure and downloads the required default dependencies to write Scala program.

    Create Maven project

  6. Select Next.

  7. Provide relevant values for GroupId, ArtifactId, and Version. The following values are used in this tutorial:

    • GroupId: com.microsoft.spark.example
    • ArtifactId: SparkSimpleApp
  8. Select Next.

  9. Verify the settings and then select Next.

  10. Verify the project name and location, and then select Finish. The project will take a few minutes to import.

  11. Once the project has imported, from the left pane navigate to SparkSimpleApp > src > test > scala > com > microsoft > spark > example. Right-click MySpec, and then select Delete.... You do not need this file for the application. Select OK in the dialog box.

  12. In the subsequent steps, you update the pom.xml to define the dependencies for the Spark Scala application. For those dependencies to be downloaded and resolved automatically, you must configure Maven accordingly.

  13. From the File menu, select Settings to open the Settings window.

  14. From the Settings window, navigate to Build, Execution, Deployment > Build Tools > Maven > Importing.

  15. Select the Import Maven projects automatically checkbox.

  16. Select Apply, and then select OK. You will then be returned to the project window.

    Configure Maven for automatic downloads

  17. From the left pane, navigate to src > main > scala > com.microsoft.spark.example, and then double-click App to open App.scala.

  18. Replace the existing sample code with the following code and save the changes. This code reads the data from the HVAC.csv (available on all HDInsight Spark clusters), retrieves the rows that only have one digit in the sixth column, and writes the output to /HVACOut under the default storage container for the cluster.

    package com.microsoft.spark.example
    
    import org.apache.spark.SparkConf
    import org.apache.spark.SparkContext
    
    /**
      * Test IO to wasb
      */
    object WasbIOTest {
      def main (arg: Array[String]): Unit = {
        val conf = new SparkConf().setAppName("WASBIOTest")
        val sc = new SparkContext(conf)
    
        val rdd = sc.textFile("wasb:///HdiSamples/HdiSamples/SensorSampleData/hvac/HVAC.csv")
    
        //find the rows which have only one digit in the 7th column in the CSV
        val rdd1 = rdd.filter(s => s.split(",")(6).length() == 1)
    
        rdd1.saveAsTextFile("wasb:///HVACout")
      }
    }
    
  19. In the left pane, double-click pom.xml.

  20. Within <project>\<properties> add the following segments:

      <scala.version>2.11.8</scala.version>
      <scala.compat.version>2.11.8</scala.compat.version>
      <scala.binary.version>2.11</scala.binary.version>
    
  21. Within <project>\<dependencies> add the following segments:

       <dependency>
         <groupId>org.apache.spark</groupId>
         <artifactId>spark-core_${scala.binary.version}</artifactId>
         <version>2.3.0</version>
       </dependency>
    

    Save changes to pom.xml.

  22. Create the .jar file. IntelliJ IDEA enables creation of JAR as an artifact of a project. Perform the following steps.

    1. From the File menu, select Project Structure....

    2. From the Project Structure window, navigate to Artifacts > the plus symbol + > JAR > From modules with dependencies....

      Create JAR

    3. In the Create JAR from Modules window, select the folder icon in the Main Class text box.

    4. In the Select Main Class window, select the class that appears by default and then select OK.

      Create JAR

    5. In the Create JAR from Modules window, ensure the extract to the target JAR option is selected, and then select OK. This setting creates a single JAR with all dependencies.

      Create JAR

    6. The Output Layout tab lists all the jars that are included as part of the Maven project. You can select and delete the ones on which the Scala application has no direct dependency. For the application, you are creating here, you can remove all but the last one (SparkSimpleApp compile output). Select the jars to delete and then select the negative symbol -.

      Create JAR

      Ensure sure the Include in project build checkbox is selected, which ensures that the jar is created every time the project is built or updated. Select Apply and then OK.

    7. To create the jar, navigate to Build > Build Artifacts > Build. The project will compile in about 30 seconds. The output jar is created under \out\artifacts.

      Create JAR

Run the application on the Apache Spark cluster

To run the application on the cluster, you can use the following approaches:

Next step

In this article, you learned how to create an Apache Spark scala application. Advance to the next article to learn how to run this application on an HDInsight Spark cluster using Livy.