Added delete option to database storage.

venv/Lib/site-packages/grpc/_plugin_wrapping.py

@@ -0,0 +1,101 @@
+# Copyright 2015 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+
+import collections
+import logging
+import threading
+
+import grpc
+from grpc import _common
+from grpc._cython import cygrpc
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class _AuthMetadataContext(
+        collections.namedtuple('AuthMetadataContext', (
+            'service_url',
+            'method_name',
+        )), grpc.AuthMetadataContext):
+    pass
+
+
+class _CallbackState(object):
+
+    def __init__(self):
+        self.lock = threading.Lock()
+        self.called = False
+        self.exception = None
+
+
+class _AuthMetadataPluginCallback(grpc.AuthMetadataPluginCallback):
+
+    def __init__(self, state, callback):
+        self._state = state
+        self._callback = callback
+
+    def __call__(self, metadata, error):
+        with self._state.lock:
+            if self._state.exception is None:
+                if self._state.called:
+                    raise RuntimeError(
+                        'AuthMetadataPluginCallback invoked more than once!')
+                else:
+                    self._state.called = True
+            else:
+                raise RuntimeError(
+                    'AuthMetadataPluginCallback raised exception "{}"!'.format(
+                        self._state.exception))
+        if error is None:
+            self._callback(metadata, cygrpc.StatusCode.ok, None)
+        else:
+            self._callback(None, cygrpc.StatusCode.internal,
+                           _common.encode(str(error)))
+
+
+class _Plugin(object):
+
+    def __init__(self, metadata_plugin):
+        self._metadata_plugin = metadata_plugin
+
+    def __call__(self, service_url, method_name, callback):
+        context = _AuthMetadataContext(_common.decode(service_url),
+                                       _common.decode(method_name))
+        callback_state = _CallbackState()
+        try:
+            self._metadata_plugin(
+                context, _AuthMetadataPluginCallback(callback_state, callback))
+        except Exception as exception:  # pylint: disable=broad-except
+            _LOGGER.exception(
+                'AuthMetadataPluginCallback "%s" raised exception!',
+                self._metadata_plugin)
+            with callback_state.lock:
+                callback_state.exception = exception
+                if callback_state.called:
+                    return
+            callback(None, cygrpc.StatusCode.internal,
+                     _common.encode(str(exception)))
+
+
+def metadata_plugin_call_credentials(metadata_plugin, name):
+    if name is None:
+        try:
+            effective_name = metadata_plugin.__name__
+        except AttributeError:
+            effective_name = metadata_plugin.__class__.__name__
+    else:
+        effective_name = name
+    return grpc.CallCredentials(
+        cygrpc.MetadataPluginCallCredentials(_Plugin(metadata_plugin),
+                                             _common.encode(effective_name)))