From 6502cf0713acb68e65b15000659680d3ad366c91 Mon Sep 17 00:00:00 2001
From: Jan David Mol <mol@astron.nl>
Date: Tue, 1 Dec 2020 15:52:52 +0100
Subject: [PATCH] Graceful fallback for non-existing OPC-UA nodes, and moved
connect logic to dedicated function
---
RCUSCC/RCUSCC/RCUSCC.py | 46 +++++++++++++++++++++++++++--------------
1 file changed, 31 insertions(+), 15 deletions(-)
diff --git a/RCUSCC/RCUSCC/RCUSCC.py b/RCUSCC/RCUSCC/RCUSCC.py
index 109d8b7ea..ec878508a 100644
--- a/RCUSCC/RCUSCC/RCUSCC.py
+++ b/RCUSCC/RCUSCC/RCUSCC.py
@@ -160,7 +160,36 @@ class RCUSCC(Device):
# ---------------
def get_pcc_node(self, node):
- return self.pcc_node.get_child(["{}:{}".format(self.name_space_index, node)])
+ try:
+ return self.pcc_node.get_child(["{}:{}".format(self.name_space_index, node)])
+ except opcua.ua.uaerrors._auto.BadNoMatch:
+ self.error_stream("Could not find PCC node %s, using a dummy", node)
+
+ class DummyNode:
+ def get_value(self):
+ pass
+
+ def set_value(self, val):
+ pass
+
+ return DummyNode()
+
+
+ def _connect(self):
+ self.debug_stream("Connecting to OPC-UA server %s:%d...", self.OPC_Server_Name, self.OPC_Server_Port)
+
+ self.client = opcua.Client("opc.tcp://{}:{}/".format(self.OPC_Server_Name, self.OPC_Server_Port), self.OPC_Time_Out * 1000)
+ self.client.connect()
+ self.debug_stream("Connecting to OPC-UA server %s:%d done.", self.OPC_Server_Name, self.OPC_Server_Port)
+
+ try:
+ self.name_space_index = self.client.get_namespace_index("http://lofar.eu")
+ except Exception as e:
+ self.warn_stream("Cannot determine the OPC-UA name space index. Will try and use the default = 2.")
+ self.name_space_index = 2
+
+ self.obj_node = self.client.get_objects_node()
+ self.pcc_node = self.obj_node.get_child(["{}:PCC".format(self.name_space_index)])
def init_device(self):
@@ -211,20 +240,7 @@ class RCUSCC(Device):
# Set defaults to property values.
try:
- self.debug_stream("Connecting to OPC-UA server %s:%d...", self.OPC_Server_Name, self.OPC_Server_Port)
-
- self.client = opcua.Client("opc.tcp://{}:{}/".format(self.OPC_Server_Name, self.OPC_Server_Port), self.OPC_Time_Out * 1000)
- self.client.connect()
- self.debug_stream("Connecting to OPC-UA server %s:%d done.", self.OPC_Server_Name, self.OPC_Server_Port)
-
- try:
- self.name_space_index = self.client.get_namespace_index("http://lofar.eu")
- except Exception as e:
- self.warn_stream("Cannot determine the OPC-UA name space index. Will try and use the default = 2.")
- self.name_space_index = 2
-
- self.obj_node = self.client.get_objects_node()
- self.pcc_node = self.obj_node.get_child(["{}:PCC".format(self.name_space_index)])
+ self._connect()
self.debug_stream("Mapping OPC-UA MP/CP to attributes...")
--
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