Load example GraphSON file in Gremlin with Cassandra

[Yordi Verkroost]

I'm trying to load the example Graph of the Gods file that is distributed with Titan with the loadGraphSON function. I have executed the following steps and are working with Titan 0.5.4 with Hadoop 2.

1. Downloaded and unpacked a fresh Titan 0.5.4 with Hadoop 2.
   
2. Started Titan, Rexster, Cassandra, ElasticSearch with the command
   bin/titan.sh -c cassandra-es start
   
   
   
3. Run Gremlin with:
   bin/gremlin.sh
   
   
   
4. Open a new TitanFactory instance with the required settings:
   g = TitanFactory.open('conf/titan-cassandra-es.properties')
   
   
   
5. Then I tried to load the Graph of the Gods from the examples-directory with
   g.loadGraphSON("examples/graph-of-the-gods")
   
   
   

I do not get an error, but trying to show all vertices with g.V returns nothing. Am I executing the rights steps here, or am I doing something wrong?

[Daniel Kuppitz]

Hi Yordi,

1) the filename should be examples/graph-of-the-gods.json

2) you can also use GraphOfTheGodsFactory.load(g) which will also create indexes and type definitions

3) just for your info: it's not necessary to start Rexster, if you just want to check things out in the REPL

Cheers,

Daniel

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[Yordi Verkroost]

Hi Daniel,

Thanks for your answer. The missing .json filetype was a typo, I'm sorry for that. When executing the loadGraphSON function with the proper file path, the JSON-file containing the Graph of the Gods is still not loaded into Gremlin (e.g. g.V returns no nodes).

gremlin> g.loadGraphSON("examples/graph-of-the-gods.json")
==>null
gremlin> g.V
13:40:57 WARN  com.thinkaurelius.titan.graphdb.transaction.StandardTitanTx  - Query requires iterating over all vertices [()]. For better performance, use indexes

I'm aware of the fact that I can use the built-in GraphofTheGodsFactory in this specific case (and this indeeds loads the Graph of the Gods successfully), but my final goal is to load a custom .json-file of a custom graph into Gremlin (or Rexster), in order to create and load a new Titan graph. Then, I would like to store this custom graph using the Cassandra storage backend.

My custom .json-file has the following syntax. I think this is the right way to represent a Titan graph in JSON, but please correct me if I'm wrong.

{"username": "AntonioAquino", "first_name": "Antonio", "last_name": "Aquino", "_outE": [{"_label": "knows", "_id": 16767, "_inV": 2199023293923}, ...], "creation_date": "2010-04-16T00:43:28.313+0000", "_inE": [{"_label": "hasCreator", "_id": 72, "_outV": 34359738458}, ...], "_id": 1099511693994, "type": "person"}

Regards,

Yordi

Op maandag 20 april 2015 11:50:09 UTC+2 schreef Daniel Kuppitz:

[Daniel Kuppitz]

The GraphSON file is made for use with GraphSONInputFormat. If you haven't done any Titan/Hadoop jobs yet, please check the Hadoop section in the docs: http://s3.thinkaurelius.com/docs/titan/0.5.4/hadoop.html

Once you know how to execute a Titan/Hadoop job, you will find a sample configuration under conf/hadoop/titan-graphson.properties to load the aforementioned GraphSON file.

Cheers,

Daniel

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[Stephen Mallette]

just to close the loop here, the issue is discussed here on SO: http://stackoverflow.com/a/29746503/1831717

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[Charlie Harrison]

Hi Yordi,

I think you want this: https://github.com/tinkerpop/blueprints/wiki/GraphSON-Reader-and-Writer-Library

In a Gremlin shell it would be something like:

InputStream in = FileInputStream("examples/graph-of-the-gods.json")
GraphSONReader.inputGraph(g, in)

Hope that helps.

Cheers,

Charlie