Remove dependency on AWS Encryption SDK for HOOK types (#260)

* Remove dependency on AWS Encryption SDK for HOOK types

src/cloudformation_cli_python_lib/exceptions.py

@@ -106,7 +106,3 @@ def __init__(self, hook_type_name: str, target_type_name: str):
 
 class Unknown(_HandlerError):
     pass
-
-
-class _EncryptionError(Exception):
-    pass

src/cloudformation_cli_python_lib/hook.py

@@ -6,14 +6,7 @@
 from typing import Any, Callable, MutableMapping, Optional, Tuple, Type, Union
 
 from .boto3_proxy import SessionProxy, _get_boto_session
-from .cipher import Cipher, KmsCipher
-from .exceptions import (
-    AccessDenied,
-    InternalFailure,
-    InvalidRequest,
-    _EncryptionError,
-    _HandlerError,
-)
+from .exceptions import InternalFailure, InvalidRequest, _HandlerError
 from .interface import (
     BaseHookHandlerRequest,
     HandlerErrorCode,
@@ -173,31 +166,16 @@ def _parse_request(
     ]:
         try:
             event = HookInvocationRequest.deserialize(event_data)
-            cipher: Cipher = KmsCipher(
-                event.requestData.hookEncryptionKeyArn,
-                event.requestData.hookEncryptionKeyRole,
-            )
-
-            caller_credentials = cipher.decrypt_credentials(
-                event.requestData.callerCredentials
-            )
-            provider_credentials = cipher.decrypt_credentials(
-                event.requestData.providerCredentials
-            )
-
-            caller_sess = _get_boto_session(caller_credentials)
-            provider_sess = _get_boto_session(provider_credentials)
+            caller_sess = _get_boto_session(event.requestData.callerCredentials)
+            provider_sess = _get_boto_session(event.requestData.providerCredentials)
             # credentials are used when rescheduling, so can't zero them out (for now)
             invocation_point = HookInvocationPoint[event.actionInvocationPoint]
             callback_context = event.requestContext.callbackContext or {}
-        except _EncryptionError as e:
-            LOG.exception("Failed to decrypt credentials")
-            raise AccessDenied(f"{e} ({type(e).__name__})") from e
         except Exception as e:
             LOG.exception("Invalid request")
             raise InvalidRequest(f"{e} ({type(e).__name__})") from e
 
-        return ((caller_sess, provider_sess)), invocation_point, callback_context, event
+        return (caller_sess, provider_sess), invocation_point, callback_context, event
 
     def _cast_hook_request(
         self, request: HookInvocationRequest

src/cloudformation_cli_python_lib/utils.py

@@ -204,22 +204,48 @@ def deserialize(cls, json_data: MutableMapping[str, Any]) -> "HookRequestContext
             return HookRequestContext()
         return HookRequestContext(**json_data)
 
+    def serialize(self) -> Mapping[str, Any]:
+        return {key: value for key, value in self.__dict__.items() if value is not None}
+
 
 @dataclass
 class HookRequestData:
     targetName: str
     targetType: str
     targetLogicalId: str
     targetModel: Mapping[str, Any]
-    callerCredentials: Optional[str] = None
-    providerCredentials: Optional[str] = None
+    callerCredentials: Optional[Credentials] = None
+    providerCredentials: Optional[Credentials] = None
     providerLogGroupName: Optional[str] = None
-    hookEncryptionKeyArn: Optional[str] = None
-    hookEncryptionKeyRole: Optional[str] = None
+
+    def __init__(self, **kwargs: Any) -> None:
+        dataclass_fields = {f.name for f in fields(self)}
+        for k, v in kwargs.items():
+            if k in dataclass_fields:
+                setattr(self, k, v)
 
     @classmethod
     def deserialize(cls, json_data: MutableMapping[str, Any]) -> "HookRequestData":
-        return HookRequestData(**json_data)
+        req_data = HookRequestData(**json_data)
+        for key in json_data:
+            if not key.endswith("Credentials"):
+                continue
+            creds = json_data.get(key)
+            if creds:
+                cred_data = json.loads(creds)
+                setattr(req_data, key, Credentials(**cred_data))
+        return req_data
+
+    def serialize(self) -> Mapping[str, Any]:
+        return {
+            key: {k: v for k, v in value.items() if v is not None}
+            if key == "targetModel"
+            else value.__dict__.copy()
+            if key.endswith("Credentials")
+            else value
+            for key, value in self.__dict__.items()
+            if value is not None
+        }
 
 
 @dataclass
@@ -252,6 +278,15 @@ def deserialize(cls, json_data: MutableMapping[str, Any]) -> Any:
         )
         return event
 
+    def serialize(self) -> Mapping[str, Any]:
+        return {
+            key: value.serialize()
+            if key in ("requestData", "requestContext")
+            else value
+            for key, value in self.__dict__.items()
+            if value is not None
+        }
+
 
 @dataclass
 class UnmodelledHookRequest:

src/setup.py

@@ -15,7 +15,6 @@
     python_requires=">=3.6",
     install_requires=[
         "boto3>=1.10.20",
-        "aws-encryption-sdk==3.1.1",
         'dataclasses;python_version<"3.7"',
     ],
     license="Apache License 2.0",