Improve type annotations for Python connectors.

fleetspeak_python/fleetspeak/server_connector/connector.py

@@ -357,25 +357,31 @@ class ServiceClient(metaclass=abc.ABCMeta):
   @abc.abstractmethod
   def __init__(
       self,
-      service_name,
-  ):
+      service_name: str,
+  ) -> None:
     """Abstract constructor for ServiceClient.
 
     Args:
-      service_name: string; The Fleetspeak service name to communicate with.
+      service_name: The Fleetspeak service name to communicate with.
     """
 
   @abc.abstractmethod
-  def Send(self, message):
+  def Send(
+      self,
+      message: common_pb2.Message,
+  ) -> None:
     """Sends a message to the Fleetspeak server."""
 
   @abc.abstractmethod
-  def Listen(self, process_callback):
+  def Listen(
+      self,
+      callback: Callable[[common_pb2.Message, grpc.ServicerContext], None],
+  ) -> None:
     """Listens to messages from the Fleetspeak server.
 
     Args:
-      process_callback: A callback to be executed when a messages arrives from
-        the Fleetspeak server. See the process argument of Servicer.__init__.
+      callback: A callback to be executed when a messages arrives from the
+        Fleetspeak server. See the process argument of Servicer.__init__.
     """
 
 
@@ -392,24 +398,23 @@ class InsecureGRPCServiceClient(ServiceClient):
 
   def __init__(
       self,
-      service_name,
-      fleetspeak_message_listen_address=None,
-      fleetspeak_server=None,
-      threadpool_size=5,
+      service_name: str,
+      fleetspeak_message_listen_address: Optional[str] = None,
+      fleetspeak_server: Optional[str] = None,
+      threadpool_size: int = 5,
   ):
     """Constructor.
 
     Args:
-      service_name: string The name of the service to communicate as.
-      fleetspeak_message_listen_address: string The connection's read end
-        address. If unset, the argv flag fleetspeak_message_listen_address will
-        be used. If still unset, the connection will not be open for reading and
-        Listen() will raise NotConfigured.
-      fleetspeak_server: string The connection's write end address. If unset,
-        the argv flag fleetspeak_server will be used. If still unset, the
-        connection will not be open for writing and Send() will raise
-        NotConfigured.
-      threadpool_size: int The number of threads to use to process messages.
+      service_name: The name of the service to communicate as.
+      fleetspeak_message_listen_address: The connection's read end address. If
+        unset, the argv flag fleetspeak_message_listen_address will be used. If
+        still unset, the connection will not be open for reading and Listen()
+        will raise NotConfigured.
+      fleetspeak_server: The connection's write end address. If unset, the argv
+        flag fleetspeak_server will be used. If still unset, the connection will
+        not be open for writing and Send() will raise NotConfigured.
+      threadpool_size: The number of threads to use to process messages.
 
     Raises:
       NotConfigured:
@@ -449,24 +454,33 @@ def __init__(
           "Fleetspeak GRPCService client connected to %s", fleetspeak_server
       )
 
-  def Send(self, message):
+  def Send(
+      self,
+      message: common_pb2.Message,
+  ) -> None:
     """Send one message.
 
     Deprecated, users should migrate to call self.outgoing.InsertMessage
     directly.
+
+    Args:
+      message: A message to send.
     """
     if not self.outgoing:
       raise NotConfigured("Send address not provided.")
     self.outgoing.InsertMessage(message)
 
-  def Listen(self, process):
+  def Listen(
+      self,
+      callback: Callable[[common_pb2.Message, grpc.ServicerContext], None],
+  ) -> None:
     if self._listen_address is None:
       raise NotConfigured("Listen address not provided.")
     self._server = grpc.server(
         futures.ThreadPoolExecutor(max_workers=self._threadpool_size)
     )
     self._server.add_insecure_port(self._listen_address)
-    servicer = Servicer(process, self._service_name)
+    servicer = Servicer(callback, self._service_name)
     grpcservice_pb2_grpc.add_ProcessorServicer_to_server(servicer, self._server)
     self._server.start()
     logging.info(