macos-instructions.md

Getting Started with Spark .NET on MacOS

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

Pre-requisites

• Download and install .NET Core 2.1 SDK
• Install Java 8
  • Select the appropriate version for your operating system e.g., jdk-8u231-macosx-x64.dmg.
  • Install using the installer and verify you are able to run java from your command-line
• Download and install Apache Spark 2.4.4:
  • Add the necessary environment variables SPARK_HOME e.g., ~/bin/spark-2.4.4-bin-hadoop2.7/

    export SPARK_HOME=~/bin/spark-2.4.4-bin-hadoop2.7/
    export PATH="$SPARK_HOME/bin:$PATH"
    source ~/.bashrc

• 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., /bin/Microsoft.Spark.Worker/).
  • IMPORTANT Create a new environment variable using export DOTNET_WORKER_DIR <your_path> and set it to the directory where you downloaded and extracted the Microsoft.Spark.Worker (e.g., /bin/Microsoft.Spark.Worker/).
  • Make sure the worker is marked as executable and remove any "quarantined" attributes, e.g.:

    chmod 755 /bin/Microsoft.Spark.Worker/Microsoft.Spark.Worker
    xattr -d com.apple.quarantine /bin/Microsoft.Spark.Worker/*

Authoring a .NET for Apache Spark App

• Use the dotnet CLI to create a console application.

  dotnet new console -o HelloSpark
  

• Install Microsoft.Spark Nuget package into the project from the spark nuget.org feed - see Ways to install Nuget Package

  cd HelloSpark
  dotnet add package Microsoft.Spark
  

• Replace the contents of the Program.cs file with the following code:

  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();
          }
      }
  }

• Use the dotnet CLI to build the application:

  dotnet build

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., ~/spark/bin/spark-submit).

• The output of the application should look similar to the output below:

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