Merge branch 'L2SS-1220-expose-whether-opcua-hardware-can-be-reached' into 'master'

L2SS-1220 added connection test attribute

Closes L2SS-1220

See merge request !576

tangostationcontrol/tangostationcontrol/clients/opcua_client.py

@@ -8,11 +8,12 @@ import socket
 import asyncua
 import numpy
 from asyncua import Client
+
 from tangostationcontrol.clients.comms_client import AsyncCommClient
 
 logger = logging.getLogger()
 
-__all__ = ["OPCUAConnection", "ProtocolAttribute"]
+__all__ = ["OPCUAConnection", "ProtocolAttribute", "test_OPCUA_connection"]
 
 numpy_to_OPCua_dict = {
     numpy.int8: asyncua.ua.VariantType.SByte,
@@ -366,3 +367,18 @@ class ProtocolAttribute:
             raise TypeError(
                 f"Cannot write value to OPC-UA attribute '{attribute_name}': tried to convert data type {our_type} to expected server type {expected_server_type}, server reports type {actual_server_type}"
             ) from e
+
+
+async def test_OPCUA_connection(server, port):
+    """
+    This function exist in order to test whether an OPC ua server can be reached
+    """
+
+    try:
+        client = Client(f"opc.tcp://{server}:{port}/", 2)
+        await client.connect()
+        await client.disconnect()
+        return True
+    except BaseException as e:
+        logger.debug("Testing OPCua connection failed", exc_info=True)
+        return False

tangostationcontrol/tangostationcontrol/clients/snmp_client.py

@@ -303,3 +303,29 @@ class MIBLoader:
 
     def load_pymib(self, mib_name):
         self.mibBuilder.loadModules(mib_name)
+
+
+def test_SNMP_connection(community, host, port=161):
+    """
+    Attempts to read a single SNMP point with the given parameters
+    sysUpTime is chosen because it is pretty much Ubiquitous point.
+    """
+
+    iterator = hlapi.getCmd(
+        hlapi.SnmpEngine(),
+        hlapi.CommunityData(community, mpModel=1),
+        hlapi.UdpTransportTarget((host, port), timeout=2, retries=1),
+        hlapi.ContextData(),
+        hlapi.ObjectType(hlapi.ObjectIdentity("SNMPv2-MIB", "sysUpTime", 0)),
+    )
+
+    errorIndication, errorStatus, errorIndex, _ = next(iterator)
+
+    if errorIndication or errorStatus or errorIndex:
+        # if not (None, 0, 0) there has been some error
+        logger.debug(
+            f"Connection test failed. errorIndication: {errorIndication}, errorStatus: {errorStatus}, errorIndex: {errorIndex}"
+        )
+        return False
+    else:
+        return True

tangostationcontrol/tangostationcontrol/devices/interfaces/opcua_device.py

@@ -12,7 +12,10 @@ import numpy
 
 # PyTango imports
 from tango.server import device_property, attribute
-from tangostationcontrol.clients.opcua_client import OPCUAConnection
+from tangostationcontrol.clients.opcua_client import (
+    OPCUAConnection,
+    test_OPCUA_connection,
+)
 from tangostationcontrol.common.lofar_logging import log_exceptions
 from tangostationcontrol.devices.interfaces.lofar_device import LOFARDevice
 
@@ -67,6 +70,25 @@ class OPCUADevice(LOFARDevice):
         doc="OPC-UA attributes that this device requested, but which are not exposed on the server. These attributes are replaced with a no-op and thus do not function as expected.",
     )
 
+    can_connect_R = attribute(
+        dtype=bool,
+    )
+
+    def read_can_connect_R(self):
+        """
+        Test whether we can connect with the OPC-ua server
+        Sets up an OPC ua connection from scratch, as it cannot be assumed
+        that self.opcua_connection has been created or functions
+        """
+        try:
+            loop = asyncio.get_running_loop()
+        except RuntimeError as _e:
+            loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(loop)
+        return loop.run_until_complete(
+            test_OPCUA_connection(self.OPC_Server_Name, self.OPC_Server_Port)
+        )
+
     # --------
     # overloaded functions
     # --------
@@ -77,7 +99,7 @@ class OPCUADevice(LOFARDevice):
 
         # set up the OPC ua client
         self.opcua_connection = OPCUAConnection(
-            "opc.tcp://{}:{}/".format(self.OPC_Server_Name, self.OPC_Server_Port),
+            f"opc.tcp://{self.OPC_Server_Name}:{self.OPC_Server_Port}/",
             self.OPC_namespace,
             self.OPC_Time_Out,
             self.Fault,

tangostationcontrol/tangostationcontrol/devices/interfaces/snmp_device.py

@@ -10,8 +10,12 @@ import os
 
 import pkg_resources
 from pysmi import debug
-from tango.server import device_property
-from tangostationcontrol.clients.snmp_client import SNMPClient, MIBLoader
+from tango.server import device_property, attribute
+from tangostationcontrol.clients.snmp_client import (
+    SNMPClient,
+    MIBLoader,
+    test_SNMP_connection,
+)
 from tangostationcontrol.common.lofar_logging import (
     device_logging_to_python,
     log_exceptions,
@@ -42,6 +46,16 @@ class SNMPDevice(LOFARDevice):
 
     SNMP_version = device_property(dtype="DevULong", mandatory=True)
 
+    can_connect_R = attribute(
+        dtype=bool,
+    )
+
+    def read_can_connect_R(self):
+        """
+        Test whether we can connect with the SNMP server
+        """
+        return test_SNMP_connection(self.SNMP_community, self.SNMP_host)
+
     @log_exceptions()
     def configure_for_initialise(self):
         # set up the SNMP client

tangostationcontrol/tangostationcontrol/integration_test/default/client/test_opcua_client_against_server.py

@@ -4,7 +4,10 @@
 import asyncua
 import numpy
 
-from tangostationcontrol.clients.opcua_client import OPCUAConnection
+from tangostationcontrol.clients.opcua_client import (
+    OPCUAConnection,
+    test_OPCUA_connection,
+)
 
 from tangostationcontrol.integration_test import base
 
@@ -199,3 +202,16 @@ class TestClientServer(base.IntegrationAsyncTestCase):
                 await test_client._call_method(["throws"])
         finally:
             await test_client.stop()
+
+    async def test_connection(self):
+        port = 14846
+
+        # test connection while server does not yet exist
+        result = await test_OPCUA_connection("127.0.0.1", port)
+        self.assertFalse(result)
+
+        await self.setup_server(port)
+
+        # test connection while server has been started
+        result = await test_OPCUA_connection("127.0.0.1", port)
+        self.assertTrue(result)