aws_credentials_provider binding (#90)

Only exposing "default chain" and "static" providers for now

.gitmodules

@@ -19,3 +19,6 @@
 [submodule "aws-c-compression"]
 	path = aws-c-compression
 	url = git://github.com/awslabs/aws-c-compression
+[submodule "aws-c-auth"]
+	path = aws-c-auth
+	url = git://github.com/awslabs/aws-c-auth

awscrt/__init__.py

@@ -14,7 +14,13 @@
 from sys import version_info
 from weakref import WeakSet
 
-__all__ = ['io', 'mqtt', 'crypto', 'http']
+__all__ = [
+    'auth',
+    'crypto',
+    'http',
+    'io',
+    'mqtt',
+]
 
 
 class NativeResource(object):

awscrt/auth.py

@@ -0,0 +1,111 @@
+# Copyright 2010-2019 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.
+
+from __future__ import absolute_import
+import _awscrt
+from awscrt import isinstance_str, NativeResource
+from awscrt.io import ClientBootstrap
+from concurrent.futures import Future
+
+
+class Credentials(object):
+    """
+    Credentials are the public/private data needed to sign an authenticated AWS request.
+    """
+
+    __slots__ = ('access_key_id', 'secret_access_key', 'session_token')
+
+    def __init__(self, access_key_id, secret_access_key, session_token=None):
+        assert isinstance_str(access_key_id)
+        assert isinstance_str(secret_access_key)
+        assert isinstance_str(session_token) or session_token is None
+
+        self.access_key_id = access_key_id
+        self.secret_access_key = secret_access_key
+        self.session_token = session_token
+
+
+class CredentialsProviderBase(NativeResource):
+    """
+    Base class for providers that source the Credentials needed to sign an authenticated AWS request.
+    """
+
+    def get_credentials(self):
+        """
+        Asynchronously fetch Credentials.
+
+        Returns a Future which will contain Credentials (or an exception)
+        when the call completes. The call may complete on a different thread.
+        """
+        future = Future()
+
+        def _on_complete(error_code, access_key_id, secret_access_key, session_token):
+            try:
+                if error_code:
+                    future.set_exception(Exception(error_code))  # TODO: Actual exceptions for error_codes
+                else:
+                    credentials = Credentials(access_key_id, secret_access_key, session_token)
+                    future.set_result(credentials)
+
+            except Exception as e:
+                future.set_exception(e)
+
+        try:
+            _awscrt.credentials_provider_get_credentials(self._binding, _on_complete)
+        except Exception as e:
+            future.set_result(e)
+
+        return future
+
+    def close(self):
+        """
+        Signal a provider (and all linked providers) to cancel pending queries and
+        stop accepting new ones.  Useful to hasten shutdown time if you know the provider
+        is going away.
+        """
+        _awscrt.credentials_provider_shutdown(self._binding)
+
+
+class DefaultCredentialsProviderChain(CredentialsProviderBase):
+    """
+    Providers source the Credentials needed to sign an authenticated AWS request.
+    This is the default provider chain used by most AWS SDKs.
+
+    Generally:
+
+    (1) Environment
+    (2) Profile
+    (3) (conditional, off by default) ECS
+    (4) (conditional, on by default) EC2 Instance Metadata
+    """
+
+    def __init__(self, client_bootstrap):
+        assert isinstance(client_bootstrap, ClientBootstrap)
+
+        super(DefaultCredentialsProviderChain, self).__init__()
+        self._binding = _awscrt.credentials_provider_new_chain_default(client_bootstrap)
+
+
+class StaticCredentialsProvider(CredentialsProviderBase):
+    """
+    Providers source the Credentials needed to sign an authenticated AWS request.
+    This is a simple provider that just returns a fixed set of credentials
+    """
+
+    def __init__(self, access_key_id, secret_access_key, session_token=None):
+        assert isinstance_str(access_key_id)
+        assert isinstance_str(secret_access_key)
+        assert isinstance_str(session_token) or session_token is None
+
+        super(StaticCredentialsProvider, self).__init__()
+        self._binding = _awscrt.credentials_provider_new_static(access_key_id, secret_access_key, session_token)

setup.py

@@ -99,6 +99,7 @@ def __init__(self, name, extra_cmake_args=[]):
 AWS_LIBS.append(AwsLib('aws-c-cal'))
 AWS_LIBS.append(AwsLib('aws-c-compression'))
 AWS_LIBS.append(AwsLib('aws-c-http'))
+AWS_LIBS.append(AwsLib('aws-c-auth'))
 AWS_LIBS.append(AwsLib('aws-c-mqtt'))
 
 

source/auth.h

@@ -0,0 +1,30 @@
+#ifndef AWS_CRT_PYTHON_AUTH_H
+#define AWS_CRT_PYTHON_AUTH_H
+/*
+ * Copyright 2010-2019 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.
+ */
+#include "module.h"
+
+PyObject *aws_py_credentials_provider_get_credentials(PyObject *self, PyObject *args);
+PyObject *aws_py_credentials_provider_shutdown(PyObject *self, PyObject *args);
+
+PyObject *aws_py_credentials_provider_new_chain_default(PyObject *self, PyObject *args);
+PyObject *aws_py_credentials_provider_new_static(PyObject *self, PyObject *args);
+
+/* Given a python object, return a pointer to its underlying native type.
+ * If NULL is returned, a python error has been set */
+
+struct aws_credentials_provider *aws_py_get_credentials_provider(PyObject *credentials_provider);
+
+#endif // AWS_CRT_PYTHON_AUTH_H