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Rule activation mode

Beta feature

This new feature (i.e., rule_activation_mode: many_by_group) is a beta feature, some cases could not work as designed. Please report them using issues.

This feature was designed at MAIF when the idea to use Arta as a simple process execution engine came about.

Our goal was to handle different rules of data processing inside an ETL pipeline.

It's actually quite simple ⚡

Illustration

Traditionaly, Arta is evaluating rules (like most rules engines) like this:

---
title: one_by_group
---
flowchart
  s((Start))
  e((End))
  subgraph Group_1
    r1(Rule 1, conditions False)-->r2(Rule 2, conditions True)-.not evaluated.->r3(Rule 3, conditions True)   
  end
    r2-.execute.->a2(Action A)   
  subgraph Group_2
    r1b(Rule 1, conditions True)-.not evaluated.->r2b(Rule 2, conditions False)-.not evaluated.->r3b(Rule 3, conditions True)
  end
  s-->r1
  r1b-.execute.->a1b(Action B)
  r2-->r1b  
  r3-.->r1b  
  r1b-->e
  r3b-.->e

Only one rule is activated (i.e., meaning one action is triggered) by rule group.

But if we need to use Arta to execute simple workflows, we need a control flow like this one:

---
title: many_by_group
---
flowchart
  s((Start))
  e((End))
  subgraph Group_1
    r1(Rule 1, conditions False)-->r2(Rule 2, conditions True)-->r3(Rule 3, conditions True)   
  end
    r2-.execute.->a2(Action A)
    r3-.execute.->a3(Action B)        
  subgraph Group_2
    r1b(Rule 1, conditions True)-->r2b(Rule 2, conditions False)-->r3b(Rule 3, conditions True)
  end
  s-->r1
  r1b-.execute.->a1b(Action C)
  r3b-.execute.->a3b(Action D)    
  r3-->r1b
  r3b-->e

All rules are evaluated.

Therefore, many rules can be activated (i.e., meaning many actions can be triggered) by rule group.

Setting

You just need to add somewhere in the YAML configuration file of Arta the following setting:

One by group

This traditional flow of control is the default one:

1
rule_activation_mode: one_by_group

Default value

Because it is the default value, it is useless to add this line in the configuration.

Many by group

This is the flow of control of a process execution engine:

1
rule_activation_mode: many_by_group

That's all! You are all set 👍