Control unicode encoding behaviour based on execution environment.

awslambdaric/lambda_runtime_feature_handler.py

@@ -0,0 +1,21 @@
+"""
+Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+"""
+import os
+from .lambda_runtime_features import feature_list
+
+
+class FeatureGate:
+    def __init__(self, execution_env=os.environ.get("AWS_EXECUTION_ENV")):
+        self.__execution_env = execution_env
+
+    def is_feature_enabled(self, feature_name) -> bool:
+        if self.__execution_env is None or self.__execution_env in feature_list.get(
+            feature_name
+        ):
+            return True
+        else:
+            return False
+
+
+feature_handler = FeatureGate()

awslambdaric/lambda_runtime_features.py

@@ -0,0 +1,6 @@
+"""
+Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+"""
+feature_list = {
+    "lambda_marshaller_ensure_ascii_false": {"AWS_Lambda_python3.12"},
+}

awslambdaric/lambda_runtime_marshaller.py

@@ -8,14 +8,18 @@
 import simplejson as json
 
 from .lambda_runtime_exception import FaultException
+from .lambda_runtime_feature_handler import feature_handler
 
 
 # simplejson's Decimal encoding allows '-NaN' as an output, which is a parse error for json.loads
 # to get the good parts of Decimal support, we'll special-case NaN decimals and otherwise duplicate the encoding for decimals the same way simplejson does
 # We also set 'ensure_ascii=False' so that the encoded json contains unicode characters instead of unicode escape sequences
 class Encoder(json.JSONEncoder):
     def __init__(self):
-        super().__init__(use_decimal=False, ensure_ascii=False)
+        if feature_handler.is_feature_enabled("lambda_marshaller_ensure_ascii_false"):
+            super().__init__(use_decimal=False, ensure_ascii=False)
+        else:
+            super().__init__(use_decimal=False)
 
     def default(self, obj):
         if isinstance(obj, decimal.Decimal):

requirements/dev.txt

@@ -9,3 +9,4 @@ bandit>=1.6.2
 # Test requirements
 pytest>=3.0.7
 mock>=2.0.0
+parameterized>=0.9.0

tests/test_lambda_runtime_features.py

@@ -0,0 +1,51 @@
+import os
+import unittest
+from parameterized import parameterized
+from awslambdaric.lambda_runtime_features import feature_list
+from awslambdaric.lambda_runtime_feature_handler import FeatureGate
+
+
+feature_names = [(feature_name,) for feature_name in feature_list]
+execution_envs = (
+    "AWS_Lambda_python3.12",
+    "AWS_Lambda_python3.11",
+    "AWS_Lambda_python3.10",
+    "AWS_Lambda_python3.9",
+)
+execution_envs_not_enabled_lambda_marshaller_ensure_ascii_false = tuple(
+    set(execution_envs).difference(
+        feature_list.get("lambda_marshaller_ensure_ascii_false")
+    )
+)
+execution_envs_is_enabled_lambda_marshaller_ensure_ascii_false = tuple(
+    feature_list.get("lambda_marshaller_ensure_ascii_false")
+)
+
+
+class TestLambdaRuntimeFeatures(unittest.TestCase):
+    @parameterized.expand(feature_names)
+    def test_no_execution_env_all_features_enabled(self, feature_name):
+        feature_handler = FeatureGate()
+        is_feature_enabled = feature_handler.is_feature_enabled(feature_name)
+        self.assertEqual(is_feature_enabled, True)
+
+    @parameterized.expand(
+        execution_envs_not_enabled_lambda_marshaller_ensure_ascii_false
+    )
+    def test_not_enabled_lambda_marshaller_ensure_ascii_false(self, execution_env):
+        feature_handler = FeatureGate(execution_env=execution_env)
+        is_feature_enabled = feature_handler.is_feature_enabled(
+            "lambda_marshaller_ensure_ascii_false"
+        )
+
+        self.assertEqual(is_feature_enabled, False)
+
+    @parameterized.expand(
+        execution_envs_is_enabled_lambda_marshaller_ensure_ascii_false
+    )
+    def test_is_enabled_lambda_marshaller_ensure_ascii_false(self, execution_env):
+        feature_handler = FeatureGate(execution_env=execution_env)
+        is_feature_enabled = feature_handler.is_feature_enabled(
+            "lambda_marshaller_ensure_ascii_false"
+        )
+        self.assertEqual(is_feature_enabled, True)

tests/test_lambda_runtime_marshaller.py

@@ -42,4 +42,6 @@ def test_to_json_unicode_encoding(self):
         response = to_json({"price": "£1.00"})
         self.assertEqual('{"price": "£1.00"}', response)
         self.assertNotEqual('{"price": "\\u00a31.00"}', response)
-        self.assertEqual(19, len(response.encode('utf-8')))  # would be 23 bytes if a unicode escape was returned
+        self.assertEqual(
+            19, len(response.encode("utf-8"))
+        )  # would be 23 bytes if a unicode escape was returned