Merge branch 'L2SS-333-fix-commclient-connect' into 'master'

L2SS-333: Improve CommClient.connect signature

Closes L2SS-333

See merge request !95

devices/clients/comms_client.py

@@ -63,9 +63,10 @@ class CommClient(AbstractCommClient, Thread):
     def connect(self):
         """
         Function used to connect to the client.
+
+        Throws an Exception if the connection cannot be established.
         """
         self.connected = True
-        return True
 
     def disconnect(self):
         """
@@ -74,22 +75,15 @@ class CommClient(AbstractCommClient, Thread):
         self.connected = False
 
     def run(self):
-
-        # Explicitly connect
-        if not self.connect():
-            # hardware or infra is down -- needs fixing first
-            self.fault_func()
-            return
-
         self.stopping = False
         while not self.stopping:
-            # keep trying to connect
             if not self.connected:
-                if self.connect():
-                    pass
-                else:
-                    # we retry only once, to catch exotic network issues. if the infra or hardware is down,
-                    # our device cannot help, and must be reinitialised after the infra or hardware is fixed.
+                # we (re)try only once, to catch exotic network issues. if the infra or hardware is down,
+                # our device cannot help, and must be reinitialised after the infra or hardware is fixed.
+                try:
+                    self.connect()
+                except Exception as e:
+                    self.streams.error_stream("Fault condition in communication detected.", e)
                     self.fault_func()
                     return
 

devices/clients/opcua_client.py

@@ -59,7 +59,6 @@ class OPCUAConnection(AsyncCommClient):
 
         try:
             await self.client.connect()
-            self.connected = True
         except (socket.error, IOError, OSError) as e:
             raise IOError(f"Could not connect to OPC-UA server {self._servername()}") from e
 

devices/test/clients/test_client.py

@@ -22,10 +22,7 @@ class test_client(CommClient):
         super().__init__(fault_func, streams, try_interval)
 
         # Explicitly connect
-        if not self.connect():
-            # hardware or infra is down -- needs fixing first
-            fault_func()
-            return
+        self.connect()
 
     def connect(self):
         """
@@ -34,7 +31,6 @@ class test_client(CommClient):
         self.streams.debug_stream("the example client doesn't actually connect to anything silly")
 
         self.connected = True  # set connected to true
-        return True  # if succesfull, return true. otherwise return false
 
     def disconnect(self):
         self.connected = False  # always force a reconnect, regardless of a successful disconnect