feat(compatability): Check Python Runtime (aws#185)

src/dynamodb_encryption_sdk/__init__.py

@@ -11,6 +11,7 @@
 # ANY KIND, either express or implied. See the License for the specific
 # language governing permissions and limitations under the License.
 """DynamoDB Encryption Client."""
+from dynamodb_encryption_sdk.compatability import _warn_deprecated_python
 from dynamodb_encryption_sdk.encrypted.client import EncryptedClient
 from dynamodb_encryption_sdk.encrypted.item import (
     decrypt_dynamodb_item,
@@ -22,6 +23,8 @@
 from dynamodb_encryption_sdk.encrypted.table import EncryptedTable
 from dynamodb_encryption_sdk.identifiers import __version__
 
+_warn_deprecated_python()
+
 __all__ = (
     "decrypt_dynamodb_item",
     "decrypt_python_item",

src/dynamodb_encryption_sdk/compatability.py

@@ -0,0 +1,39 @@
+# Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+# http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+"""Contains logic for checking the Python Version"""
+import sys
+import warnings
+
+DEPRECATION_DATE_MAP = {"1.x": "2022-07-08", "2.x": "2022-07-15"}
+
+
+def _warn_deprecated_python():
+    """Template for deprecation of Python warning."""
+    deprecated_versions = {
+        (2, 7): {"date": DEPRECATION_DATE_MAP["2.x"]},
+        (3, 4): {"date": DEPRECATION_DATE_MAP["2.x"]},
+        (3, 5): {"date": "2021-11-10"},
+    }
+    py_version = (sys.version_info.major, sys.version_info.minor)
+    minimum_version = (3, 6)
+
+    if py_version in deprecated_versions:
+        params = deprecated_versions[py_version]
+        warning = (
+            "aws-dynamodb-encryption will no longer support Python {}.{} "
+            "starting {}. To continue receiving service updates, "
+            "bug fixes, and security updates please upgrade to Python {}.{} or "
+            "later. For more information, see SUPPORT_POLICY.rst: "
+            "https://github.com/aws/aws-dynamodb-encryption-python/blob/master/SUPPORT_POLICY.rst"
+        ).format(py_version[0], py_version[1], minimum_version[0], minimum_version[1], params["date"])
+        warnings.warn(warning, DeprecationWarning)

test/pylintrc

@@ -10,6 +10,7 @@ disable =
     protected-access,  # raised when calling _ methods
     redefined-outer-name,  # raised when using pytest-mock
     unused-argument,  # raised when patches and fixtures are needed but not called
+    no-self-use,  # raised on Classes in tests used for logically grouping tests
     # All below are disabled because we need to support Python 2
     useless-object-inheritance,
     raise-missing-from,

test/unit/test_compatability.py

@@ -0,0 +1,38 @@
+# Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+# http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+"""Unit test suite for dynamodb_encryption_sdk.compatability."""
+import sys
+
+import mock
+import pytest
+
+from dynamodb_encryption_sdk.compatability import _warn_deprecated_python
+
+pytestmark = [pytest.mark.unit, pytest.mark.local]
+
+
+class TestWarnDeprecatedPython:
+    def test_happy_version(self):
+        with mock.patch.object(sys, "version_info") as v_info:
+            v_info.major = 3
+            v_info.minor = 6
+            with pytest.warns(None) as record:
+                _warn_deprecated_python()
+            assert len(record) == 0
+
+    def test_below_warn(self):
+        with mock.patch.object(sys, "version_info") as v_info:
+            v_info.major = 2
+            v_info.minor = 7
+            with pytest.warns(DeprecationWarning):
+                _warn_deprecated_python()