gremlin-python (gremthon) allows you to use Python syntax when traversing property graphs...

Install jython in your home directory

Download http://search.maven.org/remotecontent?filepath=org/python/jython-installer/2.7-b3/jython-installer-2.7-b3.jar

Run:

$ java -jar jython-installer-2.7-b3.jar

jython doesn't seem to work well with pip so we'll use easy_install to fetch 3rd party dependencies:

$ ~/jython2.7b3/bin/jython -c "$(curl -fsSL http://peak.telecommunity.com/dist/ez_setup.py)"

Then you can install additional dependencies like:

$ ~/jython2.7b3/bin/easy_install nose
$ ~/jython2.7b3/bin/easy_install rednose
$ ~/jython2.7b3/bin/easy_install requests

You can load up an interactive jython session with all of the jars that ship with titan by setting the GREMTHON_JAR_DIRS environment variable:

$ export GREMTHON_JAR_DIRS=/titan-0.5.3-hadoop2/lib/

Run a local, interactive gremthon session:

$ ~/jython2.7b3/bin/jython -i gremthon.py

That will automatically load up a sample graph so that you can follow http://gremlindocs.com/ except with Python syntax

Run all the python tests

$ ~/jython2.7b3/bin/nosetests --rednose

Compile, test and package the gremlin-python jar:

$ mvn clean package

To utilize Python syntax from within a rexster console, you'll need to drop in a couple of jar files and edit some xml configuration.

Edit conf/rexster-cassandra-es.xml (or the configuration file you're using) in your titan distribution directory to include:

<script-engine>
    <name>gremlin-python</name>
</script-engine>

There should already be a script-engine defined for gremlin-groovy. You can just paste that snippet for gremlin-python below it.

You'll also need to drop the files gremlin-python-{version}.jar and jython-standalone-{version}.jar into your titan lib directory. gremlin-python has been tested with jython-standalone-2.7-b3.jar. You can find a gremlin-python jar file for each release at https://github.com/pokitdok/gremlin-python/releases The jython standalone jar can be found at http://search.maven.org/remotecontent?filepath=org/python/jython-standalone/2.7-b3/jython-standalone-2.7-b3.jar

After restarting titan + rexster, you should see python available in your rexster console:

$ ./bin/rexster-console.sh -l python
        (l_(l
(_______( 0 0
(        (-Y-) <woof>
l l-----l l
l l,,   l l,,
opening session [127.0.0.1:8184]
?h for help

rexster[python]> g = rexster.getGraph("graph")
==>null
rexster[python]> [v.name for v in g.V]
==>hercules
rexster[python]> g.V.has('name','hercules')
==>v[256]
rexster[python]> g.V.has('name','hercules').name
==>hercules
rexster[python]> g.V.has('name','hercules').age
==>30

If you have problems connecting to a remote titan graph (that's using elasticsearch) when you're working within an interactive jython session, try placing the names.txt file from elasticsearch somewhere on the path or in your current working directory. It seems that some class loader differences exist between an interactive jython session and working within rexster. names.txt can be found properly within rexster but not when working with jython. You can grab a copy of names.txt here: https://github.com/elasticsearch/elasticsearch/blob/master/src/main/resources/config/names.txt or from within the elasticsearch jar file.

This library aims to support and is tested against these JVM versions:

• openjdk7
• oraclejdk7
• oraclejdk8

Copyright (c) 2015 PokitDok, Inc. The MIT License (MIT) (See LICENSE for details.)