How to let the Titan graph database working with Google App Engine?

Question

I can deploy my titan database web app on Tomcat v7.0 , but it failed when I was deploying the same app on Google App Engine . Here is the error message:

java.lang.IllegalArgumentException: Could not instantiate implementation: com.thinkaurelius.titan.diskstorage.cassandra.thrift.CassandraThriftStoreManager
at com.thinkaurelius.titan.diskstorage.Backend.instantiate(Backend.java:355)
at com.thinkaurelius.titan.diskstorage.Backend.getImplementationClass(Backend.java:367)
at com.thinkaurelius.titan.diskstorage.Backend.getStorageManager(Backend.java:311)
at com.thinkaurelius.titan.diskstorage.Backend.<init>(Backend.java:121)
at com.thinkaurelius.titan.graphdb.configuration.GraphDatabaseConfiguration.getBackend(GraphDatabaseConfiguration.java:1163)
at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.<init>(StandardTitanGraph.java:75)
at com.thinkaurelius.titan.core.TitanFactory.open(TitanFactory.java:40)
   ...

Part of the Java code is as follows:

Configuration conf = new BaseConfiguration();
conf.setProperty("storage.backend","cassandrathrift");
conf.setProperty("storage.hostname","127.0.0.1");
TitanGraph g = TitanFactory.open(conf);

Thank you!

Answer 1

I don't know how Titan works, but from the stack trace I can figure out that it requires some Cassandra backend for storage which is not available on AppEngine. You may use Compute Engine for running the Titan part of your application. Hopefully soon you will have one more option with AppEngine managed VM.