YARE

YARE is big data native Rules Engine built ground up. It includes a easy-to-understand Business Readable DSL. YARE provides an alternative computational model instead of the usual imperative model, which consists of commands in sequence with conditionals and loops. This rules engine is based on a Production Rule System. Production rules, each of which has a when clause defining the condition for firing the rule and a action that is execute when the condition is true.

YARE has been built ground-up to address the needs of business data transformation for big data systems. It supports application of production rules for both Batch and Realtime system.

YARE Provides

• A Inference Engine that implements Forward Chaining
  • CDAP Plugin -- Transform
  • CDAP Plugin -- Action
• Rule Management Service,
• Rule Store &
• FUTURE Rules Management Web Interface.

YARE Rule Construct

Following is the construct of a rule within YARE.

rule "rule-id" {
  description "Every rule requires a description"
  when ( condition ) 
  then {
    wrangler directive;
    wrangler directive;
  }
}

Each rule is defined by a rule-id. Each rule also consists of mandatory description followed by a condition that will be evaluated by the inference engine. If the condition evaluates to true, the rule is fired and directives within the then section are executed.

YARE Rulebook Construct

Rulebook is a collection of Rules that can be composed dynamically. A Rulebook can consists of one or more Rules. Following is a simple example of a rulebook that can be defined within YARE.

/**
 * This is rule book for normalizing the processing of titanic file. 
 * The rules are applied using an inference engine with forward chaining
 * Rule firing defines the ordering of how the rules are applied to 
 * the input record.
 */
rulebook "Titanic Feed Normalization" {
  version 1

  meta {
    description "This rule book applies transformation on the titanic feed."
    source "titanic-rules.xslx"
    user "joltie"
  }

  rule "remove-first-line" {
    description "Removes first line when offset is zero"
    when(present(offset) && offset == 0) then {
      filter-row-if-true true;
    }
  }

  rule "parse-as-csv" {
    description "Parses body"
    when(present(body)) then {
      parse-as-csv body ',' false;
      drop body;
      set columns offset,PassengerId,Survived,Pclass,Name,Sex,Age,SibSp,Parch,Ticket,Fare,Cabin,Embarked;
      cleanse-column-names;
    }
  }

  rule "rename-sex-to-gender" {
    description "Rename sex field to gender"
    when(present(sex)) then {
      rename sex gender;
    }
  }

  rule "single-character-gender" {
    description "Converts gender to single character"
    when(present(gender) && gender.length() > 1) then {
      cut-character gender gender 1-1;
      uppercase gender;
    }
  }

  rule "missing-age" {
    description "If age is missing, send it to error"
    when (!present(age)) then {
      send-to-error true;
    }
  }
  
  rule "remove-fare-less-than-8.06" {
    description "Send to error fares that are less that 8.06"
    when (fare < 8.06) then {
      send-to-error true;
    }
  }
}

More information

Please read the wiki pages for more information.