/// <summary>
/// Handler for the standard "keep alive" event sent by all OPC UA servers
/// </summary>
private static void StandardClient_KeepAlive(Session session, KeepAliveEventArgs e)
{
// Ignore if we are shutting down.
if (PublisherShutdownInProgress == true)
{
return;
}
if (e != null && session != null && session.ConfiguredEndpoint != null)
{
OpcSession opcSession = null;
try
{
OpcSessionsSemaphore.Wait();
var opcSessions = OpcSessions.Where(s => s.Session != null);
opcSession = opcSessions.Where(s => s.Session.ConfiguredEndpoint.EndpointUrl.Equals(session.ConfiguredEndpoint.EndpointUrl)).FirstOrDefault();
if (!ServiceResult.IsGood(e.Status))
{
Trace($"Session endpoint: {session.ConfiguredEndpoint.EndpointUrl} has Status: {e.Status}");
Trace($"Outstanding requests: {session.OutstandingRequestCount}, Defunct requests: {session.DefunctRequestCount}");
Trace($"Good publish requests: {session.GoodPublishRequestCount}, KeepAlive interval: {session.KeepAliveInterval}");
Trace($"SessionId: {session.SessionId}");
if (opcSession != null && opcSession.State == SessionState.Connected)
{
opcSession.MissedKeepAlives++;
Trace($"Missed KeepAlives: {opcSession.MissedKeepAlives}");
if (opcSession.MissedKeepAlives >= OpcKeepAliveDisconnectThreshold)
{
Trace($"Hit configured missed keep alive threshold of {Program.OpcKeepAliveDisconnectThreshold}. Disconnecting the session to endpoint {session.ConfiguredEndpoint.EndpointUrl}.");
session.KeepAlive -= StandardClient_KeepAlive;
opcSession.Disconnect();
}
}
}
else
{
if (opcSession != null && opcSession.MissedKeepAlives != 0)
{
// Reset missed keep alive count
Trace($"Session endpoint: {session.ConfiguredEndpoint.EndpointUrl} got a keep alive after {opcSession.MissedKeepAlives} {(opcSession.MissedKeepAlives == 1 ? "was" : "were")} missed.");
opcSession.MissedKeepAlives = 0;
}
}
}
finally
{
OpcSessionsSemaphore.Release();
}
}
else
{
Trace("Keep alive arguments seems to be wrong.");
}
}
/// <summary>
/// Method to remove the node from the subscription and stop publishing telemetry to IoTHub.
/// </summary>
private ServiceResult OnUnpublishNodeCall(ISystemContext context, MethodState method, IList <object> inputArguments, IList <object> outputArguments)
{
if (inputArguments[0] == null || inputArguments[1] == null)
{
Trace("UnpublishNode: Invalid arguments!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments!"));
}
NodeId nodeId = null;
Uri endpointUri = null;
try
{
if (string.IsNullOrEmpty(inputArguments[0] as string) || string.IsNullOrEmpty(inputArguments[1] as string))
{
Trace($"UnpublishNode: Arguments (0 (nodeId), 1 (endpointUrl)) are not valid strings!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments as strings!"));
}
nodeId = inputArguments[0] as string;
endpointUri = new Uri(inputArguments[1] as string);
}
catch (UriFormatException)
{
Trace($"UnpublishNode: The endpointUrl is invalid '{inputArguments[1] as string}'!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide a valid OPC UA endpoint URL as second argument!"));
}
// find the session and stop monitoring the node.
try
{
if (PublisherShutdownInProgress)
{
return(ServiceResult.Create(StatusCodes.BadUnexpectedError, $"Publisher shutdown in progress."));
}
// find the session we need to monitor the node
OpcSession opcSession = null;
try
{
OpcSessionsSemaphore.Wait();
opcSession = OpcSessions.FirstOrDefault(s => s.EndpointUri == endpointUri);
}
catch
{
opcSession = null;
}
finally
{
OpcSessionsSemaphore.Release();
}
if (opcSession == null)
{
// do nothing if there is no session for this endpoint.
Trace($"UnpublishNode: Session for endpoint '{endpointUri.OriginalString}' not found.");
return(ServiceResult.Create(StatusCodes.BadSessionIdInvalid, "Session for endpoint of published node not found!"));
}
else
{
Trace($"UnpublishNode: Session found for endpoint '{endpointUri.OriginalString}'");
}
// remove the node from the sessions monitored items list.
opcSession.TagNodeForMonitoringStop(nodeId);
Trace("UnpublishNode: Requested to stop monitoring of node.");
// remove node from persisted config file
try
{
PublishDataSemaphore.Wait();
var entryToRemove = PublisherConfigFileEntries.Find(l => l.NodeId == nodeId && l.EndpointUri == endpointUri);
PublisherConfigFileEntries.Remove(entryToRemove);
File.WriteAllText(NodesToPublishAbsFilename, JsonConvert.SerializeObject(PublisherConfigFileEntries));
}
finally
{
PublishDataSemaphore.Release();
}
}
catch (Exception e)
{
Trace(e, $"UnpublishNode: Exception while trying to configure publishing node '{nodeId.ToString()}'");
return(ServiceResult.Create(e, StatusCodes.BadUnexpectedError, $"Unexpected error publishing node: {e.Message}"));
}
return(ServiceResult.Good);
}
/// <summary>
/// Method to start monitoring a node and publish the data to IoTHub.
/// </summary>
private ServiceResult OnPublishNodeCall(ISystemContext context, MethodState method, IList <object> inputArguments, IList <object> outputArguments)
{
if (inputArguments[0] == null || inputArguments[1] == null)
{
Trace("PublishNode: Invalid Arguments when trying to publish a node.");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments!"));
}
NodeToPublishConfig nodeToPublish;
NodeId nodeId = null;
Uri endpointUri = null;
try
{
if (string.IsNullOrEmpty(inputArguments[0] as string) || string.IsNullOrEmpty(inputArguments[1] as string))
{
Trace($"PublishNode: Arguments (0 (nodeId), 1 (endpointUrl)) are not valid strings!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments as strings!"));
}
nodeId = NodeId.Parse(inputArguments[0] as string);
endpointUri = new Uri(inputArguments[1] as string);
nodeToPublish = new NodeToPublishConfig(nodeId, endpointUri, OpcSamplingInterval, OpcPublishingInterval);
}
catch (UriFormatException)
{
Trace($"PublishNode: The EndpointUri has an invalid format '{inputArguments[1] as string}'!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide a valid OPC UA endpoint URL as second argument!"));
}
catch (Exception e)
{
Trace(e, $"PublishNode: The NodeId has an invalid format '{inputArguments[0] as string}'!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide a valid OPC UA NodeId in 'ns=' syntax as first argument!"));
}
// find/create a session to the endpoint URL and start monitoring the node.
try
{
if (PublisherShutdownInProgress)
{
return(ServiceResult.Create(StatusCodes.BadUnexpectedError, $"Publisher shutdown in progress."));
}
// find the session we need to monitor the node
OpcSession opcSession = null;
try
{
OpcSessionsSemaphore.Wait();
opcSession = OpcSessions.FirstOrDefault(s => s.EndpointUri == nodeToPublish.EndpointUri);
// add a new session.
if (opcSession == null)
{
// create new session info.
opcSession = new OpcSession(nodeToPublish.EndpointUri, OpcSessionCreationTimeout);
OpcSessions.Add(opcSession);
Trace($"PublishNode: No matching session found for endpoint '{nodeToPublish.EndpointUri.OriginalString}'. Requested to create a new one.");
}
else
{
Trace($"PublishNode: Session found for endpoint '{nodeToPublish.EndpointUri.OriginalString}'");
}
// add the node info to the subscription with the default publishing interval
opcSession.AddNodeForMonitoring(OpcPublishingInterval, OpcSamplingInterval, nodeToPublish.NodeId);
Trace($"PublishNode: Requested to monitor item with NodeId '{nodeToPublish.NodeId.ToString()}' (PublishingInterval: {OpcPublishingInterval}, SamplingInterval: {OpcSamplingInterval})");
}
finally
{
OpcSessionsSemaphore.Release();
}
// update our data
try
{
PublishDataSemaphore.Wait();
PublishConfig.Add(nodeToPublish);
// add it also to the publish file
var publisherConfigFileEntry = new PublisherConfigFileEntry()
{
EndpointUri = endpointUri,
NodeId = nodeId
};
PublisherConfigFileEntries.Add(publisherConfigFileEntry);
File.WriteAllText(NodesToPublishAbsFilename, JsonConvert.SerializeObject(PublisherConfigFileEntries));
}
finally
{
PublishDataSemaphore.Release();
}
return(ServiceResult.Good);
}
catch (Exception e)
{
Trace(e, $"PublishNode: Exception while trying to configure publishing node '{nodeToPublish.NodeId.ToString()}'");
return(ServiceResult.Create(e, StatusCodes.BadUnexpectedError, $"Unexpected error publishing node: {e.Message}"));
}
}