Get nodes flagged as monitoredOpcNodesFailedCount

[steffenbeermann]

Is your feature request related to a problem? Please describe.
We have configured around 300.000 nodes across 20+ endpoints.

We want to monitor the state of the connections and already use the metric "monitoredOpcNodesFailedCount" to check if endpoint configuration of an OPC Server is outdated and the configured nodes are not present on the server anymore.

Currently we try to get the failed nodes out of the logs, but we would like to automate this process and therfor would like to have an

Describe the solution you'd like
Provide an API Endpoint "/v2/diagnostics/monitoredopcnodesfailed" that returns a list of nodes which could not be added as monitored items and the error message of that was provided by the server.

e.g.:

[
   {
      "endpointUrl":"opc.tcp://opcplc:50000",
      "dataSetWriterGroup":"Asset1",
      "useSecurity":false,
      "opcAuthenticationMode":"UsernamePassword",
      "opcAuthenticationUsername":"Usr",
      "monitoredOpcNodesFailed":[
         {
            "node_id":"ns=2;s=0",
            "errorInfo":{
               "statusCode":2147483648,
               "symbolicId":"Bad"
            }
         },
         {
            "node_id":"ns=2;s=1",
            "errorInfo":{
               "statusCode":2150891520,
               "symbolicId":"BadNodeIdUnknown"
            }
         }
      ]
   }
]

Describe alternatives you've considered
Parsing the logs to get the monitoredOpcNodesFailed and the error codes. This has a big drawback as this requires additional parsing logic and we can not check this on demand.