A JGit SDK-backed FileSystem driver for Hadoop

This is an experimental FileSystem for Hadoop that uses the JGit SDK. This has not been heavily tested yet. Use at your own risk.

Features:

• Clones each given repo+branch once and uses a background thread to fetch updates
• Proxies through to a read-only local filesystem driver for high speed
• Default packaging uses an uber-jar for easy deployment
• Download prebuilt jar from Maven Central

Import from Maven Central

<dependency>
    <groupId>com.simiacryptus</groupId>
    <artifactId>hadoop-jgit-fs</artifactId>
    <version>0.1</version>
</dependency>

Build Instructions

Build using maven:

$ mvn package

Copy jar and various dependencies to your hadoop libs dir (run 'hadoop classpath' to find appropriate lib dir):

$ cp target/hadoop-jgit-fs-0.1.jar /usr/lib/hadoop/lib/

Add the following keys to your core-site.xml file:

<!-- necessary for Hadoop to load our filesystem driver -->
<property>
  <name>fs.git.impl</name>
  <value>com.simiacryptus.hadoop_jgit.GitFileSystem</value>
</property>

You should now be able to run commands:

$ hadoop fs -ls git://github.com/SimiaCryptus/hadoop-jgit-fs.git/master/

Tunable parameters

These may or may not improve performance. The defaults were set without much testing.

• fs.jgit.pull.lazy - Frequency (in seconds) of foreground fetches
• fs.jgit.pull.eager - Frequency (in seconds) of background fetches
• fs.jgit.dismount.seconds - Idle time (in seconds) to dismount repo driver
• fs.jgit.dismount.delete - If true, files will be removed when repo driver dismounts
• fs.jgit.datadir - Data directory to use for local storage
• fs.jgit.auth.user - Username for authentication (Optional)
• fs.jgit.auth.pass - Password for authentication (Optional)

Caveats

This is currently implemented as a FileSystem and not a AbstractFileSystem.

Changes

0.1

• Created