feat: add AWS KMS keyring and tests

Author: mattsb42-aws

doc/index.rst

@@ -15,6 +15,9 @@ Modules
     aws_encryption_sdk.caches.local
     aws_encryption_sdk.caches.null
     aws_encryption_sdk.keyrings.base
+    aws_encryption_sdk.keyrings.aws_kms
+    aws_encryption_sdk.keyrings.aws_kms.client_suppliers
+    aws_encryption_sdk.keyrings.aws_kms.client_cache
     aws_encryption_sdk.keyrings.multi
     aws_encryption_sdk.keyrings.raw
     aws_encryption_sdk.key_providers.base
@@ -40,6 +43,7 @@ Modules
     aws_encryption_sdk.internal.formatting.serialize
     aws_encryption_sdk.internal.str_ops
     aws_encryption_sdk.internal.structures
+    aws_encryption_sdk.internal.validators
     aws_encryption_sdk.internal.utils
 
 .. include:: ../CHANGELOG.rst

setup.cfg

@@ -52,4 +52,4 @@ force_grid_wrap = 0
 combine_as_imports = True
 not_skip = __init__.py
 known_first_party = aws_encryption_sdk
-known_third_party = attr,awses_test_vectors,basic_encryption,basic_file_encryption_with_multiple_providers,basic_file_encryption_with_raw_key_provider,boto3,botocore,cryptography,data_key_caching_basic,integration_test_utils,mock,pytest,pytest_mock,setuptools,six,typing,wrapt
+known_third_party = attr,awacs,aws_encryption_sdk_decrypt_oracle,awses_test_vectors,boto3,botocore,chalice,cryptography,integration_test_utils,mock,moto,pytest,pytest_mock,requests,setuptools,six,troposphere,wrapt

src/aws_encryption_sdk/internal/validators.py

@@ -0,0 +1,21 @@
+# Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+"""Common ``attrs`` validators."""
+import attr  # only used by mypy, so pylint: disable=unused-import
+import six
+
+try:  # Python 3.5.0 and 3.5.1 have incompatible typing modules
+    from typing import Any  # noqa pylint: disable=unused-import
+except ImportError:  # pragma: no cover
+    # We only actually need these imports when running the mypy checks
+    pass
+
+
+def value_is_not_a_string(instance, attribute, value):
+    # type: (Any, attr.Attribute, Any) -> None
+    """Technically a string is an iterable containing strings.
+
+    This validator lets you accept other iterators but not strings.
+    """
+    if isinstance(value, six.string_types):
+        raise TypeError("'{}' must not a string".format(attribute.name))