neo4j-contrib / Neo4j Elasticsearch
Programming Languages
== Neo4j Elastic{Search} Integration
image:https://travis-ci.org/neo4j-contrib/neo4j-elasticsearch.svg?branch=3.1["Build Status", link="https://travis-ci.org/neo4j-contrib/neo4j-elasticsearch"]
Integrates Neo4j change-feed with an ElasticSearch cluster.
The different versions of Neo4j (2.2.x, 2.3.x, 3.0.x, and 3.1.x are supported on different branches).
=== Approach
This Neo4j Kernel Extension updates an ElasticSearch instance or cluster with changes in the graph.
A transaction event listener checks changed Nodes against a given label, renders the whole node as json document and indexes all changes in bulk with ES.
=== Installation
- Download the jar from the https://github.com/neo4j-contrib/neo4j-elasticsearch/releases[latest release].
- Copy to
$NEO4J_HOME/plugins
or for Neo4j community to the plugins folder that you find on theOptions
pane. - Modify
$NEO4J_HOME/conf/neo4j.conf
accordingly (see the Example section) - Restart Neo4j
=== Example
Suppose that we keep nodes in our Neo4j instance labeled Person
and
Place
, and that we want to index the values of the first_name
and
last_name
properties of the former and name
of the latter in two
separate ElasticSearch indices named people
and places
. For that,
we would add the following directives to conf/neo4j.conf
:
http://localhost:9200 elasticsearch.index_spec=people:Person(first_name,last_name), places:Place(name)
elasticsearch.host_name=With that in place, Neo4j will now track changes to nodes labeled
Person
or Place
and keep our ES instance running on
localhost:9200
in sync.
To perform an initial import, you can force a commit by executing a Cypher query like:
MATCH n:Person SET n.first_name = n.first_name, n.last_name = n.last_name;
MATCH n:Place SET n.name = n.name;
==== ID / Labels fields
By default, the indexes created will contain fields for the Neo4j ID and Labels, named id
and labels
.
These will be auto-created as searchable fields, but, if you'd prefer they not be included,
simply add one or both of these lines to your conf/neo4j.conf
file.
elasticsearch.include_id_field=false
elasticsearch.include_labels_field=false
=== Discovery By default discovery (discovering of nodes within a cluster) is turned off. If you would like to turn discovery on, use the discovery option.
elasticsearch.discovery=true
=== Developing
To run the tests, run mvn test
. Make sure that an elastic{search} server is running on
localhost:9200
.
=== Todo
- Support indexing of relationships