1 files changed, 112 insertions, 0 deletions
diff --git a/ms/py-executor/resource_resolution/grpc/client.py b/ms/py-executor/resource_resolution/grpc/client.py
new file mode 100644
index 000000000..fee168628
--- /dev/null
+++ b/ms/py-executor/resource_resolution/grpc/client.py
@@ -0,0 +1,112 @@
+"""Copyright 2019 Deutsche Telekom.
+
+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.
+"""
+from logging import Logger, getLogger
+from types import TracebackType
+from typing import Iterable, Optional, Type
+
+from grpc import (
+    Channel,
+    insecure_channel,
+    intercept_channel,
+    secure_channel,
+    ssl_channel_credentials,
+)
+from proto.BluePrintProcessing_pb2 import ExecutionServiceInput, ExecutionServiceOutput
+from proto.BluePrintProcessing_pb2_grpc import BluePrintProcessingServiceStub
+
+from .authorization import AuthTokenInterceptor
+
+
+class Client:
+    """Resource resoulution client class."""
+
+    def __init__(
+        self,
+        server_address: str,
+        *,
+        # TLS/SSL configuration
+        use_ssl: bool = False,
+        root_certificates: bytes = None,
+        private_key: bytes = None,
+        certificate_chain: bytes = None,
+        # Authentication header configuration
+        use_header_auth: bool = False,
+        header_auth_token: str = None,
+    ) -> None:
+        """Client class initialization.
+
+        :param server_address: Address to server to connect.
+        :param use_ssl: Boolean flag to determine if secure channel should be created or not. Keyword argument.
+        :param root_certificates: The PEM-encoded root certificates. None if it shouldn't be used. Keyword argument.
+        :param private_key: The PEM-encoded private key as a byte string, or None if no private key should be used.
+            Keyword argument.
+        :param certificate_chain: The PEM-encoded certificate chain as a byte string to use or or None if
+            no certificate chain should be used. Keyword argument.
+        :param use_header_auth: Boolean flag to determine if authorization headed shoud be added for every call or not.
+            Keyword argument.
+        :param header_auth_token: Authorization token value. Keyword argument.
+        """
+        self.logger: Logger = getLogger(__name__)
+        if use_ssl:
+            self.channel: Channel = secure_channel(
+                server_address, ssl_channel_credentials(root_certificates, private_key, certificate_chain)
+            )
+            self.logger.debug(f"Create secure channel to connect with {server_address}")
+        else:
+            self.channel: Channel = insecure_channel(server_address)
+            self.logger.debug(f"Create insecure channel to connect to {server_address}")
+        if use_header_auth:
+            self.channel: Channel = intercept_channel(self.channel, AuthTokenInterceptor(header_auth_token))
+        self.stub: BluePrintProcessingServiceStub = BluePrintProcessingServiceStub(self.channel)
+
+    def close(self) -> None:
+        """Close client session.
+
+        Closes client's channel.
+        """
+        self.logger.debug("Close channel connection")
+        self.channel.close()
+
+    def __enter__(self) -> Channel:
+        """Enter Client instance context.
+
+        Return Client instance. In the context user can call methods to communicate with server.
+        On exit connection with the server is going to be closed.
+        """
+        self.logger.debug("Enter Client instance context")
+        return self
+
+    def __exit__(
+        self,
+        unused_exc_type: Optional[Type[BaseException]],
+        unused_exc_value: Optional[BaseException],
+        unused_traceback: Optional[TracebackType],
+    ) -> None:
+        """Exit Client instance context.
+
+        Close connection with the server.
+        """
+        self.logger.debug("Exit Client instance context")
+        self.close()
+
+    def process(self, messages: Iterable[ExecutionServiceInput]) -> Iterable[ExecutionServiceOutput]:
+        """Send messages to server and return responses.
+
+        :param messages: Iterable messages to send
+        :return: Iterable responses
+        """
+        for message in self.stub.process(messages):
+            self.logger.debug(f"Get response message: {message}")
+            yield message