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Connecting to server from java: can't lock berkeleyje

queshaw
 

Apparently it replaces the full path to the properties file with a relative path (conf/remote-graph.properties), which isn't found, of course.


So, I've copied them and now I can connect. 


Thanks.


On Sunday, September 11, 2022 1:20 PM, hadoopmarc@... wrote:

The stacktrace is not very helpful, unfortunately, but that is not your doing. The original example does not use an "ats" variable but instantiates g with a oneliner, but it hard to see why this could make a difference. Most likely, the code has trouble finding the conf/remote-objects.yaml file, referenced in the conf/remote-graph.properties file.

As an alternative to fiddling with your current code, you could take a look at:


Best wishes,    Marc


hadoopmarc@...
 

The stacktrace is not very helpful, unfortunately, but that is not your doing. The original example does not use an "ats" variable but instantiates g with a oneliner, but it hard to see why this could make a difference. Most likely, the code has trouble finding the conf/remote-objects.yaml file, referenced in the conf/remote-graph.properties file.

As an alternative to fiddling with your current code, you could take a look at:

https://github.com/JanusGraph/janusgraph/tree/v0.6.2/janusgraph-examples/example-remotegraph

Best wishes,    Marc
queshaw
 

D'oh... So, after that, I get a NullPointerException:


      AnonymousTraversalSource<GraphTraversalSource> ats = traversal(); // not null

      if (new File(props).exists()) // path to conf/remote-graph.properties

          g = ats.withRemote(props);


java.lang.IllegalStateException: java.lang.reflect.InvocationTargetException

at org.apache.tinkerpop.gremlin.process.remote.RemoteConnection.from(RemoteConnection.java:73)

at org.apache.tinkerpop.gremlin.process.traversal.AnonymousTraversalSource.withRemote(AnonymousTraversalSource.java:76)

at org.apache.tinkerpop.gremlin.process.traversal.AnonymousTraversalSource.withRemote(AnonymousTraversalSource.java:66)

at lnf.graph.Queries.go(Queries.java:52)

at lnf.graph.Queries.main(Queries.java:41)

Caused by: java.lang.reflect.InvocationTargetException

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:423)

at org.apache.tinkerpop.gremlin.process.remote.RemoteConnection.from(RemoteConnection.java:71)

... 4 more

Caused by: java.lang.IllegalStateException: java.lang.NullPointerException

at org.apache.tinkerpop.gremlin.driver.remote.DriverRemoteConnection.<init>(DriverRemoteConnection.java:84)

... 9 more

Caused by: java.lang.NullPointerException

at org.apache.tinkerpop.gremlin.driver.Cluster.open(Cluster.java:255)

at org.apache.tinkerpop.gremlin.driver.remote.DriverRemoteConnection.<init>(DriverRemoteConnection.java:80)

... 9 more


The server is running and I can connect from gremlin shell.


On Sunday, September 11, 2022 5:03 AM, hadoopmarc@... wrote:

You can take a look at:


Apparently, you used JanusGraphFactory, which opens an embedded JanusGraph instance in the client. If you want to client to connect to a JanusGraph serrver, you use need the g = traversal().withRemote() syntax as shown in the link above.

Best wishes,

Marc


hadoopmarc@...
 

You can take a look at:

https://docs.janusgraph.org/interactions/connecting/java/

Apparently, you used JanusGraphFactory, which opens an embedded JanusGraph instance in the client. If you want to client to connect to a JanusGraph serrver, you use need the g = traversal().withRemote() syntax as shown in the link above.

Best wishes,

Marc
queshaw
 

I should probably add I intend to use import static org.janusgraph.core.attribute.Text.* for textContains etc.

On Saturday, September 10, 2022 8:50 AM, queshaw <queshaw@...> wrote:

I'm trying to connect to janusgraph server from java. If I follow the instructions in the documentation, using this in gradle:


    implementation 'org.janusgraph:janusgraph-driver:0.6.2'

    implementation 'org.apache.tinkerpop:gremlin-driver:3.5.3'


JanusGraph and JanusGraphFactory can't be found. If I add:


    implementation 'org.janusgraph:janusgraph-core:0.6.2'


and I use conf/remote-graph.properties, I get an error message that root.storage.backend needs to be defined. I don't find that property, but if I add:


storage.backend=berkeleyje


then I get Could not find implementation class: org.janusgraph.diskstorage.berkeleyje.BerkeleyJEStoreManager


If I add:


    implementation 'org.janusgraph:janusgraph-berkeleyje:0.6.2'


then I get:


Please supply configuration parameter "storage.directory" or both "storage.root" and "graph.graphname".


If I add:


storage.directory=/somewhere/graph/berkeleyje


then I get:


/somewhere/graph/berkeleyje The environment cannot be locked for single writer access. ENV_LOCKED: The je.lck file could not be locked. Environment is invalid and must be closed.


I think that is because the server is running and the file is locked.


How can I connect to a running server remotely from java, if I'm using berkeleyje? I've been able to connect to the server to run queries from python and from gremlin shell.


Thanks.
queshaw
 

I'm trying to connect to janusgraph server from java. If I follow the instructions in the documentation, using this in gradle:


    implementation 'org.janusgraph:janusgraph-driver:0.6.2'

    implementation 'org.apache.tinkerpop:gremlin-driver:3.5.3'


JanusGraph and JanusGraphFactory can't be found. If I add:


    implementation 'org.janusgraph:janusgraph-core:0.6.2'


and I use conf/remote-graph.properties, I get an error message that root.storage.backend needs to be defined. I don't find that property, but if I add:


storage.backend=berkeleyje


then I get Could not find implementation class: org.janusgraph.diskstorage.berkeleyje.BerkeleyJEStoreManager


If I add:


    implementation 'org.janusgraph:janusgraph-berkeleyje:0.6.2'


then I get:


Please supply configuration parameter "storage.directory" or both "storage.root" and "graph.graphname".


If I add:


storage.directory=/somewhere/graph/berkeleyje


then I get:


/somewhere/graph/berkeleyje The environment cannot be locked for single writer access. ENV_LOCKED: The je.lck file could not be locked. Environment is invalid and must be closed.


I think that is because the server is running and the file is locked.


How can I connect to a running server remotely from java, if I'm using berkeleyje? I've been able to connect to the server to run queries from python and from gremlin shell.


Thanks.

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