Python UFC SDK updates (#29)

* Pass new tests

* mypy + flake

eppo_client/client.py

@@ -74,12 +74,15 @@ def get_numeric_assignment(
         default: float,
         subject_attributes: Optional[SubjectAttributes] = None,
     ) -> float:
-        return self.get_assignment_variation(
-            subject_key,
-            flag_key,
-            default,
-            subject_attributes,
-            VariationType.NUMERIC,
+        # convert to float in case we get an int
+        return float(
+            self.get_assignment_variation(
+                subject_key,
+                flag_key,
+                default,
+                subject_attributes,
+                VariationType.NUMERIC,
+            )
         )
 
     def get_boolean_assignment(
@@ -182,6 +185,15 @@ def get_assignment_detail(
 
         result = self.__evaluator.evaluate_flag(flag, subject_key, subject_attributes)
 
+        if result.variation and not check_value_type_match(
+            expected_variation_type, result.variation.value
+        ):
+            logger.error(
+                "[Eppo SDK] Variation value does not have the correct type for the flag: "
+                f"{flag_key} and variation key {result.variation.key}"
+            )
+            return None
+
         assignment_event = {
             **(result.extra_logging if result else {}),
             "allocation": result.allocation_key if result else None,
@@ -227,3 +239,20 @@ def check_type_match(
     expected_type: Optional[VariationType], actual_type: VariationType
 ):
     return expected_type is None or actual_type == expected_type
+
+
+def check_value_type_match(
+    expected_type: Optional[VariationType], value: ValueType
+) -> bool:
+    if expected_type is None:
+        return True
+    if expected_type in [VariationType.JSON, VariationType.STRING]:
+        return isinstance(value, str)
+    if expected_type == VariationType.INTEGER:
+        return isinstance(value, int)
+    if expected_type == VariationType.NUMERIC:
+        # we can convert int to float
+        return isinstance(value, float) or isinstance(value, int)
+    if expected_type == VariationType.BOOLEAN:
+        return isinstance(value, bool)
+    return False

eppo_client/eval.py

@@ -43,12 +43,8 @@ def evaluate_flag(
             if allocation.end_at and now > allocation.end_at:
                 continue
 
-            # Skip allocations when none of the rules match
-            # So we look for (rule 1) OR (rule 2) OR (rule 3) etc.
-            # If there are no rules, then we always match
-            if not allocation.rules or any(
-                matches_rule(rule, {"id": subject_key, **subject_attributes})
-                for rule in allocation.rules
+            if matches_rules(
+                allocation.rules, {"id": subject_key, **subject_attributes}
             ):
                 for split in allocation.splits:
                     # Split needs to match all shards
@@ -86,6 +82,13 @@ def hash_key(salt: str, subject_key: str) -> str:
     return f"{salt}-{subject_key}"
 
 
+def matches_rules(rules, subject_attributes):
+    # Skip allocations when none of the rules match
+    # So we look for (rule 1) OR (rule 2) OR (rule 3) etc.
+    # If there are no rules, then we always match
+    return not rules or any(matches_rule(rule, subject_attributes) for rule in rules)
+
+
 def none_result(
     flag_key: str,
     variation_type: VariationType,

eppo_client/rules.py

@@ -17,6 +17,7 @@ class OperatorType(Enum):
     LT = "LT"
     ONE_OF = "ONE_OF"
     NOT_ONE_OF = "NOT_ONE_OF"
+    IS_NULL = "IS_NULL"
 
 
 class Condition(SdkBaseModel):
@@ -40,6 +41,11 @@ def evaluate_condition(
     condition: Condition, subject_attributes: SubjectAttributes
 ) -> bool:
     subject_value = subject_attributes.get(condition.attribute, None)
+    if condition.operator == OperatorType.IS_NULL:
+        if condition.value:
+            return subject_value is None
+        return subject_value is not None
+
     if subject_value is not None:
         if condition.operator == OperatorType.MATCHES:
             return isinstance(condition.value, str) and bool(

test/client_test.py

@@ -5,7 +5,7 @@
 import httpretty  # type: ignore
 import pytest
 from eppo_client.assignment_logger import AssignmentLogger
-from eppo_client.client import EppoClient, check_type_match
+from eppo_client.client import EppoClient, check_type_match, check_value_type_match
 from eppo_client.config import Config
 from eppo_client.models import (
     Allocation,
@@ -270,3 +270,16 @@ def test_get_numeric_assignment_on_bool_feature_flag_should_return_none(test_cas
 def test_check_type_match():
     assert check_type_match(VariationType.STRING, VariationType.STRING)
     assert check_type_match(None, VariationType.STRING)
+
+
+def test_check_value_type_match():
+    assert check_value_type_match(VariationType.STRING, "hello")
+    assert check_value_type_match(VariationType.INTEGER, 1)
+    assert check_value_type_match(VariationType.NUMERIC, 1.0)
+    assert check_value_type_match(VariationType.NUMERIC, 1)
+    assert check_value_type_match(VariationType.BOOLEAN, True)
+    assert check_value_type_match(VariationType.JSON, '{"hello": "world"}')
+
+    assert not check_type_match(VariationType.STRING, 1)
+    assert not check_type_match(VariationType.INTEGER, 1.0)
+    assert not check_type_match(VariationType.BOOLEAN, "true")

test/eval_test.py

@@ -9,7 +9,13 @@
     Split,
     Shard,
 )
-from eppo_client.eval import Evaluator, FlagEvaluation, is_in_shard_range, hash_key
+from eppo_client.eval import (
+    Evaluator,
+    FlagEvaluation,
+    is_in_shard_range,
+    hash_key,
+    matches_rules,
+)
 from eppo_client.rules import Condition, OperatorType, Rule
 from eppo_client.sharders import DeterministicSharder, MD5Sharder
 
@@ -424,6 +430,46 @@ def test_eval_after_alloc(mocker):
     assert result.variation is None
 
 
+def test_matches_rules_empty():
+    rules = []
+    subject_attributes = {"size": 10}
+    assert matches_rules(rules, subject_attributes)
+
+
+def test_matches_rules_with_conditions():
+    rules = [
+        Rule(
+            conditions=[
+                Condition(attribute="size", operator=OperatorType.IS_NULL, value=True)
+            ]
+        ),
+        Rule(
+            conditions=[
+                Condition(
+                    attribute="country", operator=OperatorType.ONE_OF, value=["UK"]
+                )
+            ]
+        ),
+    ]
+    subject_attributes_1 = {"size": None, "country": "US"}
+    subject_attributes_2 = {"size": 10, "country": "UK"}
+    subject_attributes_3 = {"size": 5, "country": "US"}
+    subject_attributes_4 = {"country": "US"}
+
+    assert (
+        matches_rules(rules, subject_attributes_1) is True
+    ), f"{subject_attributes_1} should match first rule"
+    assert (
+        matches_rules(rules, subject_attributes_2) is True
+    ), f"{subject_attributes_2} should match second rule"
+    assert (
+        matches_rules(rules, subject_attributes_3) is False
+    ), f"{subject_attributes_3} should not match any rule"
+    assert (
+        matches_rules(rules, subject_attributes_4) is True
+    ), f"{subject_attributes_4} should match first rule"
+
+
 def test_seed():
     assert hash_key("salt", "subject") == "salt-subject"
 

test/rules_test.py

@@ -255,3 +255,21 @@ def test_one_of_operator_with_number():
     assert not evaluate_condition(not_one_of_condition, {"number": 10})
     assert evaluate_condition(not_one_of_condition, {"number": "11"})
     assert evaluate_condition(not_one_of_condition, {"number": 11})
+
+
+def test_is_null_operator():
+    is_null_condition = Condition(
+        operator=OperatorType.IS_NULL, value=True, attribute="size"
+    )
+    assert evaluate_condition(is_null_condition, {"size": None})
+    assert not evaluate_condition(is_null_condition, {"size": 10})
+    assert evaluate_condition(is_null_condition, {})
+
+
+def test_is_not_null_operator():
+    is_not_null_condition = Condition(
+        operator=OperatorType.IS_NULL, value=False, attribute="size"
+    )
+    assert not evaluate_condition(is_not_null_condition, {"size": None})
+    assert evaluate_condition(is_not_null_condition, {"size": 10})
+    assert not evaluate_condition(is_not_null_condition, {})