Topics

Connecting to Multiple Schemas using Java


Vinayak Bali
 

Hi,
I am trying to connect to multiple schema's through java using the Cluster method. The properties files are as follows:

gremlin-server.yaml
# Copyright 2019 JanusGraph Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

host: 0.0.0.0
port: 8182
scriptEvaluationTimeout: 30000
channelizer: org.apache.tinkerpop.gremlin.server.channel.WsAndHttpChannelizer
graphManager: org.janusgraph.graphdb.management.JanusGraphManager
graphs: {
  ConfigurationManagementGraph: conf/janusgraph-cql-configurationgraph.properties,
  graph1: conf/graph1.properties,
  graph2: conf/graph2.properties
}
scriptEngines: {
  gremlin-groovy: {
    plugins: { org.janusgraph.graphdb.tinkerpop.plugin.JanusGraphGremlinPlugin: {},
               org.apache.tinkerpop.gremlin.server.jsr223.GremlinServerGremlinPlugin: {},
               org.apache.tinkerpop.gremlin.tinkergraph.jsr223.TinkerGraphGremlinPlugin: {},
               org.apache.tinkerpop.gremlin.jsr223.ImportGremlinPlugin: {classImports: [java.lang.Math], methodImports: [java.lang.Math#*]},
               org.apache.tinkerpop.gremlin.jsr223.ScriptFileGremlinPlugin: {files: []}}}}
serializers:
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoMessageSerializerV3d0, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoMessageSerializerV3d0, config: { serializeResultToString: true }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerV3d0, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
  # Older serialization versions for backwards compatibility:
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoMessageSerializerV1d0, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoLiteMessageSerializerV1d0, config: {ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GryoMessageSerializerV1d0, config: { serializeResultToString: true }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerGremlinV2d0, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerGremlinV1d0, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistryV1d0] }}
  - { className: org.apache.tinkerpop.gremlin.driver.ser.GraphSONMessageSerializerV1d0, config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistryV1d0] }}
processors:
  - { className: org.apache.tinkerpop.gremlin.server.op.session.SessionOpProcessor, config: { sessionTimeout: 28800000 }}
  - { className: org.apache.tinkerpop.gremlin.server.op.traversal.TraversalOpProcessor, config: { cacheExpirationTime: 600000, cacheMaxSize: 1000 }}
metrics: {
  consoleReporter: {enabled: true, interval: 180000},
  csvReporter: {enabled: true, interval: 180000, fileName: /tmp/gremlin-server-metrics.csv},
  jmxReporter: {enabled: true},
  slf4jReporter: {enabled: true, interval: 180000},
  gangliaReporter: {enabled: false, interval: 180000, addressingMode: MULTICAST},
  graphiteReporter: {enabled: false, interval: 180000}}
maxInitialLineLength: 4096
maxHeaderSize: 8192
maxChunkSize: 8192
maxContentLength: 65536
maxAccumulationBufferComponents: 1024
resultIterationBatchSize: 64
writeBufferLowWaterMark: 32768
writeBufferHighWaterMark: 65536

graph1.properties

# Copyright 2019 JanusGraph Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# JanusGraph configuration sample: Cassandra & Elasticsearch over sockets
#
# This file connects to Cassandra and Elasticsearch services running
# on localhost over the CQL API and the Elasticsearch native
# "Transport" API on their respective default ports.  The Cassandra
# and Elasticsearch services must already be running before starting
# JanusGraph with this file.

# The implementation of graph factory that will be used by gremlin server
#
# Default:    org.janusgraph.core.JanusGraphFactory
# Data Type:  String
# Mutability: LOCAL
gremlin.graph=org.janusgraph.core.JanusGraphFactory

# The primary persistence provider used by JanusGraph.  This is required.
# It should be set one of JanusGraph's built-in shorthand names for its
# standard storage backends (shorthands: berkeleyje, cassandrathrift,
# cassandra, astyanax, embeddedcassandra, cql, hbase, inmemory) or to the
# full package and classname of a custom/third-party StoreManager
# implementation.
#
# Default:    (no default value)
# Data Type:  String
# Mutability: LOCAL
storage.backend=cql

# The hostname or comma-separated list of hostnames of storage backend
# servers.  This is only applicable to some storage backends, such as
# cassandra and hbase.
#
# Default:    127.0.0.1
# Data Type:  class java.lang.String[]
# Mutability: LOCAL
storage.hostname=127.0.0.1

# The name of JanusGraph's keyspace.  It will be created if it does not
# exist.
#
# Default:    janusgraph
# Data Type:  String
# Mutability: LOCAL
storage.cql.keyspace=graph1

# Whether to enable JanusGraph's database-level cache, which is shared
# across all transactions. Enabling this option speeds up traversals by
# holding hot graph elements in memory, but also increases the likelihood
# of reading stale data.  Disabling it forces each transaction to
# independently fetch graph elements from storage before reading/writing
# them.
#
# Default:    false
# Data Type:  Boolean
# Mutability: MASKABLE
cache.db-cache = true

# How long, in milliseconds, database-level cache will keep entries after
# flushing them.  This option is only useful on distributed storage
# backends that are capable of acknowledging writes without necessarily
# making them immediately visible.
#
# Default:    50
# Data Type:  Integer
# Mutability: GLOBAL_OFFLINE
#
# Settings with mutability GLOBAL_OFFLINE are centrally managed in
# JanusGraph's storage backend.  After starting the database for the first
# time, this file's copy of this setting is ignored.  Use JanusGraph's
# Management System to read or modify this value after bootstrapping.
cache.db-cache-clean-wait = 20

# Default expiration time, in milliseconds, for entries in the
# database-level cache. Entries are evicted when they reach this age even
# if the cache has room to spare. Set to 0 to disable expiration (cache
# entries live forever or until memory pressure triggers eviction when set
# to 0).
#
# Default:    10000
# Data Type:  Long
# Settings with mutability GLOBAL_OFFLINE are centrally managed in
# JanusGraph's storage backend.  After starting the database for the first
# time, this file's copy of this setting is ignored.  Use JanusGraph's
# Management System to read or modify this value after bootstrapping.
cache.db-cache-time = 180000

# Size of JanusGraph's database level cache.  Values between 0 and 1 are
# interpreted as a percentage of VM heap, while larger values are
# interpreted as an absolute size in bytes.
#
# Default:    0.3
# Data Type:  Double
# Mutability: MASKABLE
cache.db-cache-size = 0.25

# Connect to an already-running ES instance on localhost

# The indexing backend used to extend and optimize JanusGraph's query
# functionality. This setting is optional.  JanusGraph can use multiple
# heterogeneous index backends.  Hence, this option can appear more than
# once, so long as the user-defined name between "index" and "backend" is
# unique among appearances.Similar to the storage backend, this should be
# set to one of JanusGraph's built-in shorthand names for its standard
# index backends (shorthands: lucene, elasticsearch, es, solr) or to the
# full package and classname of a custom/third-party IndexProvider
# implementation.
#
# Default:    elasticsearch
# Data Type:  String
# Mutability: GLOBAL_OFFLINE
#
# Settings with mutability GLOBAL_OFFLINE are centrally managed in
# JanusGraph's storage backend.  After starting the database for the first
# time, this file's copy of this setting is ignored.  Use JanusGraph's
# Management System to read or modify this value after bootstrapping.
index.search.backend=elasticsearch

# The hostname or comma-separated list of hostnames of index backend
# servers.  This is only applicable to some index backends, such as
# elasticsearch and solr.
#
# Default:    127.0.0.1
# Data Type:  class java.lang.String[]
# Mutability: MASKABLE
index.search.hostname=127.0.0.1

graph2.properties is the same as graph1.properties only change is the schema name.

empty-sample.groovy

// Copyright 2019 JanusGraph Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// an init script that returns a Map allows explicit setting of global bindings.
def globals = [:]

// defines a sample LifeCycleHook that prints some output to the Gremlin Server console.
// note that the name of the key in the "global" map is unimportant.
globals << [hook : [
        onStartUp: { ctx ->
            ctx.logger.info("Executed once at startup of Gremlin Server.")
        },
        onShutDown: { ctx ->
            ctx.logger.info("Executed once at shutdown of Gremlin Server.")
        }
] as LifeCycleHook]

// define the default TraversalSource to bind queries to - this one will be named "g".
graph1=JanusGraphFactory.open('conf/graph1.properties')
graph2=JanusGraphFactory.open('conf/graph2.properties')
globals << [ g1 : graph1.traversal() , g2 : graph2.traversal()]

When I run the gremlin query with g1 or g2, getting the error g1/g2 not defined.
But if we use g it is using graph2 and return the result.
How can we connect to different schema's using traversals?

Thanks & Regards,
Vinayak


hadoopmarc@...
 

Hi Vinayak,

The TinkerPop ref docs gives the following code fragment for connecting with the cluster method:

Cluster cluster = Cluster.open();
GraphTraversalSource g1 = traversal().withRemote(DriverRemoteConnection.using(cluster, "g1"));
GraphTraversalSource g2 = traversal().withRemote(DriverRemoteConnection.using(cluster, "g2"));
Is this what you tried (I do not see it in your question)?

Best wishes,    Marc