Million Song Dataset

Requirements

• maven 3.5
• Java 8
• scala 2.12
• Apache Spark 2.2.0

If you use brew.sh in your mac. You can install them using:

$ brew install maven; brew install apache-spark

Setup

1. Downloading and preparing the data set (subset of Million Song dataset). Use the provided bash script as follows:

$ ./scripts/dataset_download.sh

2. In order to prepare the input data for use it with Apache Spark. You can run the paths2txt.sh script that creates a .txt file with the paths of the HDF5 files ./scripts/paths2txt.sh /path/to/dataset/folder /path/to/output.txt. For instance, by default you can use:

$ ./scripts/paths2txt.sh dataset/MillionSongSubset/data paths.txt
The paths.txt file will have the paths of each hdf5 file.

3. You can decode a particular hdf5 using the script ./scripts/characterize.sh which runs an scala application that decodes the file. By default the script will decode the hdf5 file located at src/test/resources/sample.h5. For decoding another file you can pass the path as argument:

$ ./scripts/characterize.sh dataset/MillionSongSubset/data/A/B/A/TRABACN128F425B784.h5

Processing the data.

1. You need to build the project using maven.

$ mvn package

2. Launch the spark job. You should use spark-submit in order to run the application. The entry point is the singleton com.k.msd.MsdApp which accepts 3 arguments <hd5f_paths> <output_folder> <num_partitions>. For instance, running spark locally with 4 executors, using 4 partitions for the input data:

$ /path/to/spark-submit --master local[4] --jars libs/sis-jhdf5-batteries_included.jar --class com.k.msd.MsdApp target/uber-msd-0.1.0.jar ./paths.txt ./output 4

Notice that you need to pass the argument --jars libs/sis-jhdf5-batteries_included.jar since the hdf5 library is not on the maven repository thus it is included with scope="system" in the pom.xml.