Rules Processor

Simple Business Rules Processor.

Installation

Add this line to your application's Gemfile:

gem 'rules_processor'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rules_processor

Configuration

Add to /config/initializers/rules_processor.rb class_name which will be hold actions. This actions will be executed after rule conditions are met.

require 'rules_processor'

RulesProcessor.configure do |config|
  config.actions_class = ::Rule::ActionsProcessor # Example class
end

Usage

Ruleset

Array of rules designed to process. Rules order has importance.

Rule

Rule has conditions and actions. Conditions are grouped in to logical groups: meet_all and meet_any.

Logical group	Description
meet_all	All conditions in group should match.
meet_any	Any condition in group should match.

[
  {
    meet_all: [],
    meet_any: [
        {field: 'ticket_subject', operator: 'include', value: 'return'},
        {field: 'comment_content', operator: 'include', value: 'return'}
    ],
    actions: [
        {action_name: 'ticket_set_priority', value: '1'},
        {action_name: 'ticket_assign_group', value: '3'}
    ]
  }
]

Condition

Conditions has three attributes: :field, :operator, :value

Attribute	Description
field	Proper construction of field is prefix_ + method_name, when prefix is record's class_name. Example: ticket_subject, ticket_assignee_id, comment_content
operator	[List of supported operators] (#supported-operations)
value	-

Example condition:

{ field: 'ticket_replies', operator: 'greater_than', value: '6' }

Actions

Action has three attributes :action_name, :value.

Example action:

{ action_name: 'set_status', value: '2' }

How processor works

Public interface:

RulesProcessor::Processor.new(records: {ticket: ticket, comment: comment},
                              options: {},
                              ruleset: ruleset).process

Methods to compare

You can compare against any method which is defined in class of comparable record.

For example if you want to set condition:

{ field: 'ticket_replies', operator: 'greater_than', value: '6' }

Just create method on your record class:

def replies
  replies.size
end

Supported operations

Operator	Description
is	Equality comparison for string and integers
is_not	Equality comparison for string and integers
include	Contains at least one of words
not_include	Contains none of the words
less_than	Compare integers
less_than_equal	Compare integers
greater_than	Compare integers
greater_than_equal	Compare integers

Operators to options for select

There are three groups of operators:

Group	Operators
base	is, is_not
includable	include, not_include
comparable	less_than, less_than_equal, greater_than, greater_than_equal

There is a module which returns predefined operators sets.

You can use it in such way:

operators = RulesProcessor::OperatorsToSelect

def ticket_subject_options
  operators.base + operators.includable
end

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rgrabowski/rules_processor. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.