Configuration

To configure any of these variables you can do the following:

In Rails

In either config/application.rb or one of the environment configurations (e.g. config/environments/development.rb) you can set config.neo4j.variable_name = value where variable_name and value are as described below.

Other Ruby apps

You can set configuration variables directly in the Neo4j configuration class like so: Neo4j::Config[:variable_name] = value where variable_name and value are as described below.

Variables

association_model_namespace

Default: nil

Associations defined in node models will try to match association names to classes. For example, has_many :out, :student will look for a Student class. To avoid having to use model_class: 'MyModule::Student', this config option lets you specify the module that should be used globally for class name discovery.

Of course, even with this option set, you can always override it by calling model_class: 'ClassName'.

class_name_property

Default: :_classname

Which property should be used to determine the ActiveNode class to wrap the node in

If there is no value for this property on a node the node`s labels will be used to determine the ActiveNode class

See also

Wrapping

enums_case_sensitive

Default: false

Determins whether enums property setters should be case sensitive or not.

See also

activenode-enums

include_root_in_json

Default: true

When serializing ActiveNode and ActiveRel objects, should there be a root in the JSON of the model name.

See also

http://api.rubyonrails.org/classes/ActiveModel/Serializers/JSON.html

logger

Default: nil (or Rails.logger in Rails)

A Ruby Logger object which is used to log Cypher queries (info level is used). This is only for the neo4j gem (that is, for models created with the ActiveNode and ActiveRel modules).

module_handling

Default: :none

Available values: :demodulize, :none, proc

Determines what, if anything, should be done to module names when a model’s class is set. By default, there is a direct mapping of an ActiveNode model name to the node label or an ActiveRel model to the relationship type, so MyModule::MyClass results in a label with the same name.

The :demodulize option uses ActiveSupport’s method of the same name to strip off modules. If you use a proc, it will the class name as an argument and you should return a string that modifies it as you see fit.

pretty_logged_cypher_queries

Default: nil

If true, format outputted queries with newlines and colors to be more easily readable by humans

record_timestamps

Default: false

A Rails-inspired configuration to manage inclusion of the Timestamps module. If set to true, all ActiveNode and ActiveRel models will include the Timestamps module and have :created_at and :updated_at properties.

skip_migration_check

Default: false

Prevents the neo4j gem from raising Neo4j::PendingMigrationError in web requests when migrations haven’t been run. For environments (like testing) where you need to use the neo4j:schema:load rake task to build the database instead of migrations. Automatically set to true in Rails test environments by default

timestamp_type

Default: DateTime

This method returns the specified default type for the :created_at and :updated_at timestamps. You can also specify another type (e.g. Integer).

transform_rel_type

Default: :upcase

Available values: :upcase, :downcase, :legacy, :none

Determines how relationship types as specified in associations are transformed when stored in the database. By default this is upper-case to match with Neo4j convention so if you specify an association of has_many :in, :posts, type: :has_post then the relationship type in the database will be HAS_POST

:legacy

Causes the type to be downcased and preceded by a #

:none

Uses the type as specified

wait_for_connection

Default: false

This allows you to tell the gem to wait for up to 60 seconds for Neo4j to be available. This is useful in environments such as Docker Compose. This is currently only for Rails

Instrumented events

The neo4j-core gem instruments a handful of events so that users can subscribe to them to do logging, metrics, or anything else that they need. For example, to create a block which is called any time a query is made via the neo4j-core gem:

Neo4j::Core::CypherSession::Adaptors::Base.subscribe_to_query do |message|
  puts message
end

The argument to the block (message in this case) will be an ANSI formatted string which can be outputted or stored. If you want to access this event at a lower level, subscribe_to_query is actually tied to the neo4j.core.cypher_query event to which you could subscribe to like:

ActiveSupport::Notifications.subscribe('neo4j.core.cypher_query') do |name, start, finish, id, payload|
  puts payload[:query].to_cypher
  # or
  payload[:query].print_cypher

  puts "Query took: #{(finish - start)} seconds"
end

All methods and their corresponding events:

Neo4j::Core::CypherSession::Adaptors::Base.subscribe_to_query

neo4j.core.cypher_query

Neo4j::Core::CypherSession::Adaptors::HTTP.subscribe_to_request

neo4j.core.http.request

Neo4j::Core::CypherSession::Adaptors::Bolt.subscribe_to_request

neo4j.core.bolt.request

Neo4j::Core::CypherSession::Adaptors::Embedded.subscribe_to_transaction

neo4j.core.embedded.transaction