"Gopher Holds The Rules"
Grule
import "github.com/nvnamsss/grule-rule-engine"
Rule Engine for Go
Grule is a Rule Engine library for the Golang programming language. Inspired by the acclaimed JBOSS Drools, done in a much simple manner.
Like Drools, Grule have its own DSL comparable as follows.
Drools's DRL be like :
rule "SpeedUp"
salience 10
when
$TestCar : TestCarClass( speedUp == true && speed < maxSpeed )
$DistanceRecord : DistanceRecordClass()
then
$TestCar.setSpeed($TestCar.Speed + $TestCar.SpeedIncrement);
update($TestCar);
$DistanceRecord.setTotalDistance($DistanceRecord.getTotalDistance() + $TestCar.Speed);
update($DistanceRecord);
end
And Grule's GRL be like :
rule SpeedUp "When testcar is speeding up we keep increase the speed." salience 10 {
when
TestCar.SpeedUp == true && TestCar.Speed < TestCar.MaxSpeed
then
TestCar.Speed = TestCar.Speed + TestCar.SpeedIncrement;
DistanceRecord.TotalDistance = DistanceRecord.TotalDistance + TestCar.Speed;
}
What is RuleEngine
There isn't a better explanation than the article authored by Martin Fowler. You can read the article here (RulesEngine by Martin Fowler).
Taken from TutorialsPoint website (with slight modifications),
Grule Rule Engine is a Production Rule System that uses the rule-based approach to implement an Expert System. Expert Systems are knowledge-based systems that use knowledge representations to process acquired knowledge into a knowledge base that can be used for reasoning.
A Production Rule System is Turing complete with a focus on knowledge representation to express propositional and first-order logic in a concise, non-ambiguous and declarative manner.
The brain of a Production Rules System is an Inference Engine that can scale to a large number of rules and facts. The Inference Engine matches facts and data against Production Rules – also called Productions or just Rules – to infer conclusions which result in actions.
A Production Rule is a two-part structure that uses first-order logic for reasoning over knowledge representation. A business rule engine is a software system that executes one or more business rules in a runtime production environment.
A Rule Engine allows you to define “What to Do” and not “How to do it.”
What is a Rule
(also taken from TutorialsPoint)
Rules are pieces of knowledge often expressed as, "When some conditions occur, then do some tasks."
When
<Condition is true>
Then
<Take desired Action>
The most important part of a Rule is its when part. If the when part is satisfied, the then part is triggered.
rule <rule_name> <rule_description>
<attribute> <value> {
when
<conditions>
then
<actions>
}
Advantages of a Rule Engine
Declarative Programming
Rules make it easy to express solutions to difficult problems and get the verifications as well. Unlike codes, Rules are written with less complex language; Business Analysts can easily read and verify a set of rules.
Logic and Data Separation
The data resides in the Domain Objects and the business logic resides in the Rules. Depending upon the kind of project, this kind of separation can be very advantageous.
Centralization of Knowledge
By using Rules, you create a repository of knowledge (a knowledge base) which is executable. It is a single point of truth for business policy. Ideally, Rules are so readable that they can also serve as documentation.
Agility To Change
Since business rules are actually treated as data. Adjusting the rule according to business dynamic nature become trivial. No need to re-build codes, deploy as normal software development do, you only need to roll out sets of rule and apply them to knowledge repository.
Docs
Grule's Documentation now viewable in ViewDocs. http://nvnamsss.viewdocs.io
Benchmark
Loading rules into KnowledgeBase
:
-
To load 100
rules into knowledgeBase it took 99342047 ns/op
(took the highest value) that is equal to ~99.342047ms
and (49295906 B/op
) ~49.295906MB
memory per operation
-
To load 1000
rules into knowledgeBase it took 933617752 ns/op
(took the highest value) that is equal to ~933.617752ms
and (488126636 B/op
) ~488.126636
memory per operation
Executing rules against a fact
:
-
To execute a fact against 100 rules, Grule Engine took ~9697 ns/op
(took the highest value as base) that is hardly ~0.009697ms
and 3957 B/op
which is pretty fast.
-
To execute a fact against 1000 rules, Grule Engine took ~568959 ns/op
(took the highest value as base) that is hardly ~0.568959ms
and 293710 B/op
which is also pretty fast.
You can read the detail report here
Our Contributors
Tasks and Help Wanted
Yes. We need contributors to make Grule even better and useful to the Open Source Community.
- Need to do more and more and more tests.
- Better code coverage test.
- Better commenting for go doc best practice.
- Improve function argument handling to be more fluid and intuitive.
If you really want to help us, simply Fork
the project and apply for Pull Request.
Please read our Contribution Manual and Code of Conduct