Quickstart¶

Installation¶

pip install rulez

Defining & Compiling Comparators¶

rulez provide a way to compile comparators from JSON based ruleset.

from rulez import Engine
from rulez import OperatorNotAllowedError
from rulez import NestedOperationNotAllowedError
from rulez.operator import Operator

rule = {
    "operator": "or", "value": [
        {"field": "age", "operator": "<=", "value": 16},
        {"field": "age", "operator": ">=", "value": 21},
        {"field": "age", "operator": "==", "value": 18}
    ]
}

engine = Engine()

f = engine.compile_condition('native', rule)

assert f({'age': 13}) is True
assert f({'age': 17}) is False
assert f({'age': 21}) is True
assert f({'age': 19}) is False

Available Compilation Method¶

native - compile to python condition
sqlalchemy - compile to a factory function to generate sqlalchemy filter
elasticsearch - compile a factory function that generate elasticsearch filter

Defining & Compiling Rule Chain¶

Besides compiling conditionals, rulez also provide a way to compile if-elif-else ruleset.

from rulez import Engine

rulechain = [
    {'condition': {
        'field': 'age',
        'operator': '<',
        'value': 18},
      'actions': [{
          'action': 'set',
          'parameter': {
              'field': 'category',
              'value': 'underage'
          }
      }]},
    {'condition': {
        'field': 'age',
        'operator': '>',
        'value': 50},
      'actions': [{
          'action': 'set',
          'parameter': {
              'field': 'category',
              'value': 'senior'}}]},
    {'actions': [{
        'action': 'set',
        'parameter': {
            'field': 'category',
            'value': 'adult'}}]}
]

engine = Engine()
c = engine.compile_rulechain('native', rulechain)

assert c({'age': 10}) == {'age': 10, 'category': 'underage'}
assert c({'age': 18}) == {'age': 18, 'category': 'adult'}
assert c({'age': 55}) == {'age': 55, 'category': 'senior'}

Available Compilation Method¶

native - compile to python rulechain
sqlalchemy - compile to a factory function to generate sqlalchemy query that adds a new result column