Return Fired rules actions results. venmo#34 (Update)

HISTORY.md

@@ -1,6 +1,12 @@
 History
 =========
 
+## 1.1.2
+
+Release date: 2023-6-25
+
+- Added support for returning the results for applied actions of triggered rules
+
 ## 1.1.1
 
 Release date: 2022-3-18

README.md

@@ -48,7 +48,7 @@ class ProductVariables(BaseVariables):
 
 ### 2. Define your set of actions
 
-These are the actions that are available to be taken when a condition is triggered.
+These are the actions that are available to be taken when a condition is triggered. Actions can either persist the changes directly, or can return an updated state back for any downstream use cases, or do both. 
 
 For example:
 
@@ -62,6 +62,7 @@ class ProductActions(BaseActions):
     def put_on_sale(self, sale_percentage):
         self.product.price = (1.0 - sale_percentage) * self.product.price
         self.product.save()
+        return self.product.price # optionally return some state
 
     @rule_action(params={"number_to_order": FIELD_NUMERIC})
     def order_more(self, number_to_order):
@@ -100,48 +101,59 @@ An example of the resulting python lists/dicts is:
 
 ```python
 rules = [
-# expiration_days < 5 AND current_inventory > 20
-{ "conditions": { "all": [
-      { "name": "expiration_days",
-        "operator": "less_than",
-        "value": 5,
-      },
-      { "name": "current_inventory",
-        "operator": "greater_than",
-        "value": 20,
-      },
-  ]},
-  "actions": [
-      { "name": "put_on_sale",
-        "params": {"sale_percentage": 0.25},
-      },
-  ],
-},
-
-# current_inventory < 5 OR (current_month = "December" AND current_inventory < 20)
-{ "conditions": { "any": [
-      { "name": "current_inventory",
-        "operator": "less_than",
-        "value": 5,
-      },
-    ]},
-      { "all": [
-        {  "name": "current_month",
-          "operator": "equal_to",
-          "value": "December",
+    # expiration_days < 5 AND current_inventory > 20
+    {
+        "name": "Rule for Putting Product on Sale",  # name is optional
+        "conditions": {
+            "all": [
+                {
+                    "name": "expiration_days",
+                    "operator": "less_than",
+                    "value": 5,
+                },
+                {
+                    "name": "current_inventory",
+                    "operator": "greater_than",
+                    "value": 20,
+                },
+            ]
         },
-        { "name": "current_inventory",
-          "operator": "less_than",
-          "value": 20,
-        }
-      ]},
-  },
-  "actions": [
-    { "name": "order_more",
-      "params":{"number_to_order": 40},
+        "actions": [
+            {"name": "put_on_sale", "params": {"sale_percentage": 0.25}},
+        ],
     },
-  ],
-}]
+
+    # current_inventory < 5 OR (current_month = "December" AND current_inventory < 20)
+    {
+        "name": "Rule for restocking",  # name is optional
+        "conditions": {
+            "any": [
+                {
+                    "name": "current_inventory",
+                    "operator": "less_than",
+                    "value": 5,
+                },
+                {
+                    "all": [
+                        {
+                            "name": "current_month",
+                            "operator": "equal_to",
+                            "value": "December",
+                        },
+                        {
+                            "name": "current_inventory",
+                            "operator": "less_than",
+                            "value": 20,
+                        }
+                    ]
+                }
+            ],
+            "actions": [
+                {"name": "order_more", "params": {"number_to_order": 40}},
+            ],
+        }
+    }
+]
 ```
 
 ### Export the available variables, operators and actions
@@ -213,6 +225,23 @@ for product in Products.objects.all():
            )
 ```
 
+Alternatively, `run_all_with_results` can be used to get the updated state for applied actions of triggered rules.
+
+```python
+from business_rules import run_all_with_results
+
+rules = _some_function_to_receive_from_client()
+
+for product in Products.objects.all():
+    rules_action_results = run_all_with_results(
+        rule_list=rules,
+        defined_variables=ProductVariables(product),
+        defined_actions=ProductActions(product),
+        stop_on_first_trigger=True
+    )
+
+```
+
 ## API
 
 #### Variable Types and Decorators:
@@ -271,10 +300,6 @@ Note: to compare floating point equality we just check that the difference is le
 * `shares_exactly_one_element_with`
 * `shares_no_elements_with`
 
-### Returning data to your client
-
-
-
 ## Contributing
 
 Open up a pull request, making sure to add tests for any new functionality. To set up the dev environment (assuming you're using [virtualenvwrapper](http://docs.python-guide.org/en/latest/dev/virtualenvs/#virtualenvwrapper)):

business_rules/__init__.py

@@ -1,8 +1,10 @@
-__version__ = '1.1.1'
+__version__ = '1.1.2'
 
 from .engine import run_all
+from .engine import run_all_with_results
 from .utils import export_rule_data
 
 # Appease pyflakes by "using" these exports
 assert run_all
+assert run_all_with_results
 assert export_rule_data

business_rules/engine.py

@@ -1,10 +1,10 @@
 from .fields import FIELD_NO_INPUT
 
+
 def run_all(rule_list,
             defined_variables,
             defined_actions,
             stop_on_first_trigger=False):
-
     rule_was_triggered = False
     for rule in rule_list:
         result = run(rule, defined_variables, defined_actions)
@@ -14,6 +14,42 @@ def run_all(rule_list,
                 return True
     return rule_was_triggered
 
+
+def run_all_with_results(rule_list, defined_variables, defined_actions, stop_on_first_trigger=False):
+    """
+        Runs all the rules and returns the results returned by actions of triggered rule(s).
+
+        Returns:
+            rule_results(dict): dictionary with results of actions for every triggered rule. {} if no rule triggered.
+            Uses rule's `name` as key if available, otherwise rule's index is used as key.
+        """
+    rule_results = {}
+    for ix, rule in enumerate(rule_list):
+        triggered, actions_results = run_and_get_results(rule, defined_variables,
+                                                         defined_actions)
+        if triggered:
+            rule_name = rule.get('name', ix)
+            rule_results[rule_name] = actions_results
+            if stop_on_first_trigger:
+                return rule_results
+    return rule_results
+
+
+def run_and_get_results(rule, defined_variables, defined_actions):
+    """Run the rule and get the action returned result
+    Attributes:
+        rule(dict): the rule dictionary
+        defined_variables(BaseVariables): the defined set of variables object
+        defined_actions(BaseActions): the actions object
+    """
+    actions_results = None
+    conditions, actions = rule.get('conditions'), rule.get('actions')
+    rule_triggered = check_conditions_recursively(conditions, defined_variables)
+    if rule_triggered:
+        actions_results = do_actions(actions, defined_actions)
+    return rule_triggered, actions_results
+
+
 def run(rule, defined_variables, defined_actions):
     conditions, actions = rule['conditions'], rule['actions']
     rule_triggered = check_conditions_recursively(conditions, defined_variables)
@@ -45,6 +81,7 @@ def check_conditions_recursively(conditions, defined_variables):
         assert not ('any' in keys or 'all' in keys)
         return check_condition(conditions, defined_variables)
 
+
 def check_condition(condition, defined_variables):
     """ Checks a single rule condition - the condition will be made up of
     variables, values, and the comparison operator. The defined_variables
@@ -54,20 +91,24 @@ def check_condition(condition, defined_variables):
     operator_type = _get_variable_value(defined_variables, name)
     return _do_operator_comparison(operator_type, op, value)
 
+
 def _get_variable_value(defined_variables, name):
     """ Call the function provided on the defined_variables object with the
     given name (raise exception if that doesn't exist) and casts it to the
     specified type.
 
     Returns an instance of operators.BaseType
     """
+
     def fallback(*args, **kwargs):
         raise AssertionError("Variable {0} is not defined in class {1}".format(
-                name, defined_variables.__class__.__name__))
+            name, defined_variables.__class__.__name__))
+
     method = getattr(defined_variables, name, fallback)
     val = method()
     return method.field_type(val)
 
+
 def _do_operator_comparison(operator_type, operator_name, comparison_value):
     """ Finds the method on the given operator_type and compares it to the
     given comparison_value.
@@ -76,21 +117,40 @@ def _do_operator_comparison(operator_type, operator_name, comparison_value):
     comparison_value is whatever python type to compare to
     returns a bool
     """
+
     def fallback(*args, **kwargs):
         raise AssertionError("Operator {0} does not exist for type {1}".format(
             operator_name, operator_type.__class__.__name__))
+
     method = getattr(operator_type, operator_name, fallback)
     if getattr(method, 'input_type', '') == FIELD_NO_INPUT:
         return method()
     return method(comparison_value)
 
 
 def do_actions(actions, defined_actions):
+    """ Run the actions
+    Attributes:
+        actions(list): list of dictionaries of actions. e.g: [
+            { "name": "put_on_sale",
+            "params": {"sale_percentage": 0.25},
+            }
+        ]
+    Returns:
+        actions_results(dict): Dictionary of actions results
+            e.g: {"put_on_sale: [product1, product2, ...]}
+    """
+    actions_results = {}
     for action in actions:
         method_name = action['name']
+
         def fallback(*args, **kwargs):
-            raise AssertionError("Action {0} is not defined in class {1}"\
-                    .format(method_name, defined_actions.__class__.__name__))
+            raise AssertionError(
+                "Action {0} is not defined in class {1}".format(method_name,
+                                                                defined_actions.__class__.__name__))
+
         params = action.get('params') or {}
         method = getattr(defined_actions, method_name, fallback)
-        method(**params)
+        actions_results[method_name] = method(**params)
+
+    return actions_results

tests/test_engine_logic.py

@@ -46,11 +46,53 @@ def test_run_all_stop_on_first(self, *args):
         actions = BaseActions()
 
         result = engine.run_all([rule1, rule2], variables, actions,
-                stop_on_first_trigger=True)
+                                stop_on_first_trigger=True)
         self.assertEqual(result, True)
         self.assertEqual(engine.run.call_count, 1)
         engine.run.assert_called_once_with(rule1, variables, actions)
 
+    @patch.object(engine, 'run_and_get_results')
+    def test_run_all_with_results_some_rule_triggered(self, *args):
+        """ By default, does not stop on first triggered rule. Returns True if
+        any rule was triggered, otherwise False
+        """
+        rule1 = {'name': 'rule 1', 'conditions': 'condition1', 'actions': 'action name 1'}
+        rule2 = {'name': 'rule 2', 'conditions': 'condition2', 'actions': 'action name 2'}
+        variables = BaseVariables()
+        actions = BaseActions()
+
+        def return_action1(rule, *args, **kwargs):
+            if rule['name'] == 'rule 1':
+                return True, {'action name 1': None}
+            return False, None
+
+        engine.run_and_get_results.side_effect = return_action1
+
+        result = engine.run_all_with_results([rule1, rule2], variables, actions)
+
+        self.assertDictEqual(result, {'rule 1': {'action name 1': None}})
+        self.assertEqual(engine.run_and_get_results.call_count, 2)
+
+        # switch order and try again
+        engine.run_and_get_results.reset_mock()
+
+        result = engine.run_all_with_results([rule2, rule1], variables, actions)
+        self.assertDictEqual(result, {'rule 1': {'action name 1': None}})
+        self.assertEqual(engine.run_and_get_results.call_count, 2)
+
+    @patch.object(engine, 'run_and_get_results', return_value=(True, {'action name 1': None}))
+    def test_run_all_with_results_stop_on_first(self, *args):
+        rule1 = {'name': 'rule 1', 'conditions': 'condition1', 'actions': 'action name 1'}
+        rule2 = {'name': 'rule 2', 'conditions': 'condition2', 'actions': 'action name 2'}
+        variables = BaseVariables()
+        actions = BaseActions()
+
+        result = engine.run_all_with_results([rule1, rule2], variables, actions,
+                stop_on_first_trigger=True)
+        self.assertDictEqual(result, {'rule 1': {'action name 1': None}})
+        self.assertEqual(engine.run_and_get_results.call_count, 1)
+        engine.run_and_get_results.assert_called_once_with(rule1, variables, actions)
+
     @patch.object(engine, 'check_conditions_recursively', return_value=True)
     @patch.object(engine, 'do_actions')
     def test_run_that_triggers_rule(self, *args):
@@ -78,7 +120,6 @@ def test_run_that_doesnt_trigger_rule(self, *args):
                 rule['conditions'], variables)
         self.assertEqual(engine.do_actions.call_count, 0)
 
-
     @patch.object(engine, 'check_condition', return_value=True)
     def test_check_all_conditions_with_all_true(self, *args):
         conditions = {'all': [{'thing1': ''}, {'thing2': ''}]}