windows-instructions.md

Getting Started with Spark .NET on Windows

These instructions will show you how to run a .NET for Apache Spark app using .NET Core on Windows.

Pre-requisites

• Download and install the following: .NET Core 3.1 SDK | Visual Studio 2019 | Java 1.8 | Apache Spark 2.4.1
• Download and install Microsoft.Spark.Worker release:
  • Select a Microsoft.Spark.Worker release from .NET for Apache Spark GitHub Releases page and download into your local machine (e.g., c:\bin\Microsoft.Spark.Worker\).
  • IMPORTANT Create a new environment variable DOTNET_WORKER_DIR and set it to the directory where you downloaded and extracted the Microsoft.Spark.Worker (e.g., c:\bin\Microsoft.Spark.Worker).

For detailed instructions, you can see Building .NET for Apache Spark from Source on Windows.

Authoring a .NET for Apache Spark App

• Open Visual Studio -> Create New Project -> Console App (.NET Core) -> Name: HelloSpark
• Install Microsoft.Spark Nuget package into the solution from the spark nuget.org feed - see Ways to install Nuget Package
• Write the following code into Program.cs:

  using Microsoft.Spark.Sql;
  
  namespace HelloSpark
  {
      class Program
      {
          static void Main(string[] args)
          {
              var spark = SparkSession.Builder().GetOrCreate();
              var df = spark.Read().Json("people.json");
              df.Show();
          }
      }
  }

• Build the solution

Running your .NET for Apache Spark App

• Open your terminal and navigate into your app folder:

  cd <your-app-output-directory>
  

• Create people.json with the following content:

  {"name":"Michael"}
  {"name":"Andy", "age":30}
  {"name":"Justin", "age":19}

• Run your app

  spark-submit `
  --class org.apache.spark.deploy.dotnet.DotnetRunner `
  --master local `
  microsoft-spark-<version>.jar `
  dotnet HelloSpark.dll
  

  Note: This command assumes you have downloaded Apache Spark and added it to your PATH environment variable to be able to use spark-submit, otherwise, you would have to use the full path (e.g., c:\bin\apache-spark\bin\spark-submit). For detailed instructions, you can see Building .NET for Apache Spark from Source on Windows.
• The output of the application should look similar to the output below:

  +----+-------+
  | age|   name|
  +----+-------+
  |null|Michael|
  |  30|   Andy|
  |  19| Justin|
  +----+-------+