avoid deadlock in proxy

in secop.proxy the callers modules method announceUpdate is
called from an other thread while the accessLock is locked,
creating a deadlock. solve this by creating an other lock
'updateLock' for the update.

+ add status parameter even to non-Readable proxy modules,
  in order to indicate a failed connection
+ fix an error in secop_psi/softcal.py

Change-Id: Iae7c6d5a74001150a47aa9dc99209c15d972cd5e
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/28130
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/modules.py

@@ -318,7 +318,8 @@ class Module(HasAccessibles):
         self.initModuleDone = False
         self.startModuleDone = False
         self.remoteLogHandler = None
-        self.accessLock = threading.RLock()
+        self.accessLock = threading.RLock()  # for read_* / write_* methods
+        self.updateLock = threading.RLock()  # for announceUpdate
         self.polledModules = []  # modules polled by thread started in self.startModules
         errors = []
 
@@ -495,7 +496,7 @@ class Module(HasAccessibles):
     def announceUpdate(self, pname, value=None, err=None, timestamp=None):
         """announce a changed value or readerror"""
 
-        with self.accessLock:
+        with self.updateLock:
             # TODO: remove readerror 'property' and replace value with exception
             pobj = self.parameters[pname]
             timestamp = timestamp or time.time()

secop/proxy.py

@@ -33,6 +33,7 @@ from secop.io import HasIO
 
 class ProxyModule(HasIO, Module):
     module = Property('remote module name', datatype=StringType(), default='')
+    status = Parameter('connection status', Readable.status.datatype)  # add status even when not a Readable
 
     _consistency_check_done = False
     _secnode = None
@@ -182,11 +183,12 @@ def proxy_class(remote_class, name=None):
 
     for aname, aobj in rcls.accessibles.items():
         if isinstance(aobj, Parameter):
-            pobj = aobj.merge(dict(handler=None, needscfg=False))
+            pobj = aobj.copy()
+            pobj.merge(dict(handler=None, needscfg=False))
             attrs[aname] = pobj
 
             def rfunc(self, pname=aname):
-                value, _, readerror = self._secnode.getParameter(self.name, pname)
+                value, _, readerror = self._secnode.getParameter(self.name, pname, True)
                 if readerror:
                     raise readerror
                 return value

secop_psi/softcal.py

@@ -191,7 +191,7 @@ class Sensor(Readable):
 
     def initModule(self):
         super().initModule()
-        self._rawsensor.registerCallbacks(self, ['status'])  # auto update status
+        self.rawsensor.registerCallbacks(self, ['status'])  # auto update status
         self._calib = CalCurve(self.calib)
         if self.description == '_':
             self.description = '%r calibrated with curve %r' % (self.rawsensor, self.calib)
@@ -220,4 +220,4 @@ class Sensor(Readable):
             self.status = self.Status.ERROR, self._value_error
 
     def read_value(self):
-        return self._calib(self._rawsensor.read_value())
+        return self._calib(self.rawsensor.read_value())