various small changes

- set default target unit to '$'
- shorten too verbose error message on client
- add shutdown method to server and dispatcher

Change-Id: Ib3a8b26bc31e988e45a3ff2efd734168d723d794
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/27095
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

secop/client/__init__.py

@@ -518,7 +518,7 @@ class SecopClient(ProxyClient):
         action, _, data = entry[2]  # pylint: disable=unpacking-non-sequence
         if action.startswith(ERRORPREFIX):
             errcls = self.error_map(data[0])
-            raise errcls('on SEC-Node: ' + data[1])
+            raise errcls(data[1])
         return entry[2]  # reply
 
     def request(self, action, ident=None, data=None):

secop/modules.py

@@ -642,7 +642,7 @@ class Writable(Readable):
     """basic writable module"""
 
     target = Parameter('target value of the module',
-                       default=0, readonly=False, datatype=FloatRange())
+                       default=0, readonly=False, datatype=FloatRange(unit='$'))
 
 
 class Drivable(Writable):

secop/protocol/dispatcher.py

@@ -83,6 +83,7 @@ class Dispatcher:
         self._subscriptions = {}
         self._lock = threading.RLock()
         self.restart = srv.restart
+        self.shutdown = srv.shutdown
 
     def broadcast_event(self, msg, reallyall=False):
         """broadcasts a msg to all active connections

secop/server.py

@@ -220,6 +220,10 @@ class Server:
             self._restart = True
             self.interface.shutdown()
 
+    def shutdown(self):
+        self._restart = False
+        self.interface.shutdown()
+
     def _processCfg(self):
         errors = []
         opts = dict(self.node_cfg)