Sparkle: Apache Spark applications in Haskell

Sparkle [spär′kəl]: a library for writing resilient analytics applications in Haskell that scale to thousands of nodes, using Spark and the rest of the Apache ecosystem under the hood. See this blog post for the details.

This is an early tech preview, not production ready.

Getting started

The tl;dr using the hello app as an example on your local machine:

$ stack build hello
$ stack exec -- sparkle package sparkle-example-hello
$ stack exec -- spark-submit --master 'local[1]' sparkle-example-hello.jar

Requirements:

• the Stack build tool (version 1.2 or above);
• either, the Nix package manager,
• or, OpenJDK, Gradle and Spark (version 1.6) installed from your distro.

To run a Spark application the process is as follows:

1. create an application in the apps/ folder, in-repo or as a submodule;
2. add your app to stack.yaml;
3. build the app;
4. package your app into a deployable JAR container;
5. submit it to a local or cluster deployment of Spark.

If you run into issues, read the Troubleshooting section below first.

To build:

$ stack build

You can optionally get Stack to download Spark and Gradle in a local sandbox (using Nix) for good build results reproducibility. This is the recommended way to build sparkle. Alternatively, you'll need these installed through your OS distribution's package manager for the next steps (and you'll need to tell Stack how to find the JVM header files and shared libraries).

To use Nix, set the following in your ~/.stack/config.yaml (or pass --nix to all Stack commands, see the Stack manual for more):

nix:
  enable: true

To package your app as a JAR directly consumable by Spark:

$ stack exec -- sparkle package <app-executable-name>

Finally, to run your application, for example locally:

$ stack exec -- spark-submit --master 'local[1]' <app-executable-name>.jar

The <app-executable-name> is any executable name as given in the .cabal file for your app. See apps in the apps/ folder for examples.

See here for other options, including launching a whole cluster from scratch on EC2. This blog post shows you how to get started on the Databricks hosted platform and on Amazon's Elastic MapReduce.

Non-Linux OSes

Sparkle is not currently supported on non-linux OSes, e.g. Mac OS X or Windows. If you want to build and use it from a machine using such an OS, you can use the provided Dockerfile and build everything in docker:

$ docker build -t sparkle .

will create an image named sparkle containing everything that's needed to build sparkle and Spark applications: Stack, Java 8, Gradle.

This image can be used to build sparkle then package and run applications:

# stack --docker --docker-image sparkle build
...

Note that you will need to edit the stack.yaml file to point to include directories and libraries for building the C bits that interact with the JVM:

extra-include-dirs:
  - '/usr/lib/jvm/java-1.8.0-openjdk-amd64/include'
  - '/usr/lib/jvm/java-1.8.0-openjdk-amd64/include/linux'
extra-lib-dirs:
  - '/usr/lib/jvm/java-1.8.0-openjdk-amd64/jre/lib/amd64/server/'

Once everything is built you can generate a spark package and run it using sparkle's command-line:

# stack --docker --docker-image sparkle exec sparkle package sparkle-example-hello

How it works

sparkle is a tool for creating self-contained Spark applications in Haskell. Spark applications are typically distributed as JAR files, so that's what sparkle creates. We embed Haskell native object code as compiled by GHC in these JAR files, along with any shared library required by this object code to run. Spark dynamically loads this object code into its address space at runtime and interacts with it via the Java Native Interface (JNI).

Troubleshooting

jvm library or header files not found

You'll need to tell Stack where to find your local JVM installation. Something like the following in your ~/.stack/config.yaml should do the trick, but check that the paths match up what's on your system:

extra-include-dirs: [/usr/lib/jvm/java-7-openjdk-amd64/include]
extra-lib-dirs: [/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server]

Or use --nix: since it won't use your globally installed JDK, it will have no trouble finding its own locally installed one.

Can't build sparkle on OS X

OS X is not a supported platform for now. There are several issues to make sparkle work on OS X, tracked in this ticket.

Gradle <= 2.12 incompatible with JDK 9

If you're using JDK 9, note that you'll need to either downgrade to JDK 8 or update your Gradle version, since Gradle versions up to and including 2.12 are not compatible with JDK 9.

License

Copyright (c) 2015-2016 EURL Tweag.

All rights reserved.

Sparkle is free software, and may be redistributed under the terms specified in the LICENSE file.

About

Sparkle is maintained by Tweag I/O.

Have questions? Need help? Tweet at @tweagio.