Version: export the version of transport #82

Displayed each time the transport is started with info log level:
2019-07-17 17:03:16,421 | [INFO] transport_service: Version is: 1.2.0rc1

And also available with wm-gw --version:
$ wm-gw --version
1.2.0rc1

python_transport/wirepas_gateway/transport_service.py

@@ -20,6 +20,8 @@
     GatewayAPIParsingException,
 )
 
+from wirepas_gateway import __version__ as transport_version
+
 # This constant is the actual API level implemented by this transport module (cf WP-RM-128)
 IMPLEMENTED_API_VERSION = 1
 
@@ -36,6 +38,8 @@ class TransportService(BusClient):
     MAX_HOP_LIMIT = 15
 
     def __init__(self, settings, logger=None, **kwargs):
+        self.logger = logger or logging.getLogger(__name__)
+        self.logger.info("Version is: {}".format(transport_version))
 
         super(TransportService, self).__init__(
             logger=logger,
@@ -66,8 +70,6 @@ def __init__(self, settings, logger=None, **kwargs):
 
         self.mqtt_wrapper.start()
 
-        self.logger = logger or logging.getLogger(__name__)
-
         self.logger.info("Gateway started with id: {}".format(self.gw_id))
 
     def _on_mqtt_wrapper_termination_cb(self):
@@ -613,7 +615,8 @@ def main():
 
     """
     ParserHelper()
-    parse = ParserHelper(description="Default arguments")
+    parse = ParserHelper(description="Default arguments",
+                         version=transport_version)
 
     parse.add_file_settings()
     parse.add_mqtt()

python_transport/wirepas_gateway/utils/argument_tools.py

@@ -61,6 +61,7 @@ def __init__(
         self,
         description="argument parser",
         formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+        version=None
     ):
         super(ParserHelper, self).__init__()
         self._parser = argparse.ArgumentParser(
@@ -71,6 +72,12 @@ def __init__(
         self._unknown_arguments = None
         self._arguments = None
 
+        if version is not None:
+            self.main.add_argument(
+                "--version",
+                action="version",
+                version=version)
+
     @property
     def parser(self):
         """ Returns the parser object """