JanusGraph DynamoDB backend exceptions when committing data to the database

Question

Hello: I am using JanusGraph with DynamoDB example from https://github.com/awslabs/dynamodb-janusgraph-storage-backend

Also, I am connecting to JanusGraph using Spark - Scala - Gremlin Scala framework. Everything thing works when I used Cassandra as the backend, but when I switch to using DynamoDB, I start getting backend exception errors.

My conf looks like this

val conf = new BaseConfiguration


conf.setProperty("gremlin.graph","org.janusgraph.core.JanusGraphFactory")

conf.setProperty("storage.write-time","1 ms")

conf.setProperty("storage.read-time","1 ms")
conf.setProperty("storage.backend","com.amazon.janusgraph.diskstorage.dynamodb.DynamoDBStoreManager")
conf.setProperty("storage.dynamodb.client.signing-region","us-east-1")
conf.setProperty("storage.dynamodb.client.endpoint","http://127.0.0.1:8000")
val graph = JanusGraphFactory.open(conf)

I can connect DynamoDB fine, but when I start to insert data, I run into backend exceptions.

Below is part of the error log

ERROR org.janusgraph.graphdb.database.StandardJanusGraph - Could not commit transaction [1] due to storage exception in system-commit org.janusgraph.core.JanusGraphException: Could not execute operation due to backend exception at org.janusgraph.diskstorage.util.BackendOperation.execute(BackendOperation.java:57) at org.janusgraph.diskstorage.keycolumnvalue.cache.CacheTransaction.persist(CacheTransaction.java:95) at org.janusgraph.diskstorage.keycolumnvalue.cache.CacheTransaction.flushInternal(CacheTransaction.java:143) at org.janusgraph.diskstorage.keycolumnvalue.cache.CacheTransaction.commit(CacheTransaction.java:200) at org.janusgraph.diskstorage.BackendTransaction.commit(BackendTransaction.java:150) at org.janusgraph.graphdb.database.StandardJanusGraph.commit(StandardJanusGraph.java:703) at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.commit(StandardJanusGraphTx.java:1363) at org.janusgraph.graphdb.tinkerpop.JanusGraphBlueprintsGraph$GraphTransaction.doCommit(JanusGraphBlueprintsGraph.java:272) at org.apache.tinkerpop.gremlin.structure.util.AbstractTransaction.commit(AbstractTransaction.java:105) at $line81.$read$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$anonfun$1$$anonfun$apply$1.apply(:84) at $line81.$read$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$iw$$anonfun$1$$anonfun$apply$1.apply(:80)

Any idea what is going on here. I am pretty new to DynamoDB. This was working fine in Cassandra

Answer 1

Why do you know you are connected? I think you must provide credentials into your config. For example:

conf.setProperty("storage.dynamodb.client.credentials.class-name", "com.amazonaws.auth.BasicAWSCredentials")
conf.setProperty("storage.dynamodb.client.credentials.constructor-args", "ACCESS_KEY,SECRET_KEY")