add support for targeting rule evaluation with semver (#27)

* add logic to support semver comparisons

* bump to 1.3.1

---------

Co-authored-by: Leo Romanovsky <[email protected]>

Author: vpai

CHANGELOG.md

@@ -10,7 +10,7 @@
 from eppo_client.http_client import HttpClient, SdkParams
 from eppo_client.read_write_lock import ReadWriteLock
 
-__version__ = "1.3.0"
+__version__ = "1.3.1"
 
 __client: Optional[EppoClient] = None
 __lock = ReadWriteLock()

eppo_client/__init__.py

@@ -1,5 +1,6 @@
 import numbers
 import re
+import semver
 from enum import Enum
 from typing import Any, List
 
@@ -55,9 +56,13 @@ def evaluate_condition(subject_attributes: dict, condition: Condition) -> bool:
                 value.lower() for value in condition.value
             ]
         else:
-            return isinstance(
-                subject_value, numbers.Number
-            ) and evaluate_numeric_condition(subject_value, condition)
+            # Numeric operator: value could be numeric or semver.
+            if isinstance(subject_value, numbers.Number):
+                return evaluate_numeric_condition(subject_value, condition)
+            elif is_valid_semver(subject_value):
+                return compare_semver(
+                    subject_value, condition.value, condition.operator
+                )
     return False
 
 
@@ -70,4 +75,31 @@ def evaluate_numeric_condition(subject_value: numbers.Number, condition: Conditi
         return subject_value < condition.value
     elif condition.operator == OperatorType.LTE:
         return subject_value <= condition.value
+
+    return False
+
+
+def is_valid_semver(value: str):
+    try:
+        # Parse the string. If it's a valid semver, it will return without errors.
+        semver.VersionInfo.parse(value)
+        return True
+    except ValueError:
+        # If a ValueError is raised, the string is not a valid semver.
+        return False
+
+
+def compare_semver(attribute_value: Any, condition_value: Any, operator: OperatorType):
+    if not is_valid_semver(attribute_value) or not is_valid_semver(condition_value):
+        return False
+
+    if operator == OperatorType.GT:
+        return semver.compare(attribute_value, condition_value) > 0
+    elif operator == OperatorType.GTE:
+        return semver.compare(attribute_value, condition_value) >= 0
+    elif operator == OperatorType.LT:
+        return semver.compare(attribute_value, condition_value) < 0
+    elif operator == OperatorType.LTE:
+        return semver.compare(attribute_value, condition_value) <= 0
+
     return False

eppo_client/rules.py

@@ -4,3 +4,4 @@ requests==2.31.*
 cachetools==5.3.*
 types-cachetools==5.3.*
 types-requests==2.31.*
+semver==3.0.*

requirements.txt

@@ -58,6 +58,23 @@ def test_find_matching_rule_with_numeric_value_and_regex():
     assert find_matching_rule({"age": 99}, [rule]) == rule
 
 
+def test_find_matching_rule_with_semver():
+    semver_greater_than_condition = Condition(
+        operator=OperatorType.GTE, value="1.0.0", attribute="version"
+    )
+    semver_less_than_condition = Condition(
+        operator=OperatorType.LTE, value="2.0.0", attribute="version"
+    )
+    semver_rule = Rule(
+        allocation_key="allocation",
+        conditions=[semver_less_than_condition, semver_greater_than_condition],
+    )
+
+    assert find_matching_rule({"version": "1.1.0"}, [semver_rule]) is semver_rule
+    assert find_matching_rule({"version": "2.0.0"}, [semver_rule]) is semver_rule
+    assert find_matching_rule({"version": "2.1.0"}, [semver_rule]) is None
+
+
 def test_one_of_operator_with_boolean():
     oneOfRule = Rule(
         allocation_key="allocation",