ProducerOnline Property (ISparkplugProducer)

Determines whether this Sparkplug producer (edge node or device) is online.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
ReadOnly Property ProducerOnline As Boolean

'Usage
 
Dim instance As ISparkplugProducer
Dim value As Boolean
 
value = instance.ProducerOnline

bool ProducerOnline {get;}

property bool ProducerOnline {
   bool get();
}

Remarks

Following rules define when the producer is online:

For edge nodes with no primary host configured (IEasySparkplugEdgeNode.PrimaryHostId is empty), which is the default), the edge node is considered online when it is connected to the MQTT broker.
For edge nodes with a primary host configured (when (IEasySparkplugEdgeNode.PrimaryHostId is not empty), the edge node is considered online when the primary host application is online, e.g. when ApplicationOnline is true).
The devices on an edge node are considered online when their edge node is online.

The online or offline status of the producer has the following consequences:

If the DataSourceConnectionMode is SparkplugDataSourceConnectionMode.WhenProducerOnline, the data source is connected if the producer is now online, or disconnected if the producer is now offline.
For edge nodes, if the producer status has changed to 'online', the NBIRTH message is published.
For edge nodes, if the producer status has changed to 'offline', the edge node disconnects from the MQTT broker, and reconnects.
For devices, if the data source is connected and the device is not frozen, the IsAlive property is set to true if the producer is now online, or to false if the producer is now offline. Consequently, the devices publishes the DBIRTH or DDEATH message, respectively.

The ISparkplugProducerEvents.ProducerOnlineChanged event is raised when the value of ProducerOnline has changed.

The value of ProducerOnline property on the edge node propagates automatically to the ProducerOnline property on its devices.

This method or property does not throw any exceptions, aside from execution exceptions such as System.Threading.ThreadAbortException or System.OutOfMemoryException.

Sparkplug is a trademark of Eclipse Foundation, Inc. "MQTT" is a trademark of the OASIS Open standards consortium. Other related terms are trademarks of their respective owners. Any use of these terms on this site is for descriptive purposes only and does not imply any sponsorship, endorsement or affiliation.

Example

CSharp
VB.NET

// This example shows how to set the polling (publishing) interval for the metrics on the edge node.
//
// You can use any Sparkplug application, including our SparkplugCmd utility and the SparkplugApplicationConsoleDemo
// program, to subscribe to the edge node data. 
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
// Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

using System;
using OpcLabs.EasySparkplug;

namespace SparkplugDocExamples.EdgeNode._EasySparkplugEdgeNode
{
     class PublishingInterval
    {
        static public void Main1()
        {
            // Note that the default port for the "mqtt" scheme is 1883.
            var hostDescriptor = new SparkplugHostDescriptor("mqtt://localhost");

            // Instantiate the edge node object.
            var edgeNode = new EasySparkplugEdgeNode(hostDescriptor, "easyGroup", "easySparkplugDemo");

            // Configure the publishing interval, which also defines how often the metrics are polled.
            edgeNode.PublishingInterval = 3*1000;   // 3 seconds

            // Hook the SystemConnectionStateChanged event to handle system connection state changes.
            edgeNode.SystemConnectionStateChanged += (sender, eventArgs) =>
            {
                // Display the new connection state (such as when the connection to the broker succeeds or fails).
                Console.WriteLine($"{nameof(EasySparkplugEdgeNode.SystemConnectionStateChanged)}: {eventArgs}");
            };

            // Define a metric providing random integers.
            var random = new Random();
            edgeNode.Metrics.Add(new SparkplugMetric("MyMetric").ReadValueFunction(() => random.Next()));

            // Start the edge node.
            Console.WriteLine("The edge node is starting...");
            edgeNode.Start();

            Console.WriteLine("The edge node is started.");
            Console.WriteLine();

            // Let the user decide when to stop.
            Console.WriteLine("Press Enter to stop the edge node...");
            Console.ReadLine();

            // Stop the edge node.
            Console.WriteLine("The edge node is stopping...");
            edgeNode.Stop();

            Console.WriteLine("The edge node is stopped.");
        }
    }
}

' This example shows how to set the polling (publishing) interval for the metrics on the edge node.
'
' You can use any Sparkplug application, including our SparkplugCmd utility and the SparkplugApplicationConsoleDemo
' program, to subscribe to the edge node data.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
' Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-CSharp .
' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
' a commercial license in order to use Online Forums, and we reply to every post.

Imports OpcLabs.EasySparkplug

Namespace Global.SparkplugDocExamples.EdgeNode._EasySparkplugEdgeNode
    Class PublishingInterval
        Public Shared Sub Main1()
            ' Note that the default port for the "mqtt" scheme is 1883.
            Dim hostDescriptor = New SparkplugHostDescriptor("mqtt://localhost")

            ' Instantiate the edge node object.
            Dim edgeNode = New EasySparkplugEdgeNode(hostDescriptor, "easyGroup", "easySparkplugDemo")

            ' Configure the publishing interval, which also defines how often the metrics are polled.
            edgeNode.PublishingInterval = 3 * 1000 ' 3 seconds

            ' Hook the SystemConnectionStateChanged event to handle system connection state changes.
            AddHandler edgeNode.SystemConnectionStateChanged,
                Sub(sender, eventArgs)
                    ' Display the new connection state (such as when the connection to the broker succeeds or fails).
                    Console.WriteLine($"{NameOf(EasySparkplugEdgeNode.SystemConnectionStateChanged)}: {eventArgs}")
                End Sub

            ' Define a metric providing random integers.
            Dim random = New Random()
            edgeNode.Metrics.Add(New SparkplugMetric("MyMetric").ReadValueFunction(Function() random.Next()))

            ' Start the edge node.
            Console.WriteLine("The edge node is starting...")
            edgeNode.Start()

            Console.WriteLine("The edge node is started.")
            Console.WriteLine()

            ' Let the user decide when to stop.
            Console.WriteLine("Press Enter to stop the edge node...")
            Console.ReadLine()

            ' Stop the edge node.
            Console.WriteLine("The edge node is stopping...")
            edgeNode.Stop()

            Console.WriteLine("The edge node is stopped.")
        End Sub
    End Class
End Namespace

CSharp
VB.NET

// This example shows how to connect to the data source only when the producer is online.
//
// You can use any Sparkplug application, including our SparkplugCmd utility and the SparkplugApplicationConsoleDemo
// program, to subscribe to the edge node data. 
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
// Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

using System;
using OpcLabs.EasySparkplug;

namespace SparkplugDocExamples.EdgeNode._EasySparkplugEdgeNode
{
     class DataSourceConnectionMode
    {
        static public void Main1()
        {
            // Note that the default port for the "mqtt" scheme is 1883.
            var hostDescriptor = new SparkplugHostDescriptor("mqtt://localhost");

            // Instantiate the edge node object.
            var edgeNode = new EasySparkplugEdgeNode(hostDescriptor, "easyGroup", "easySparkplugDemo");

            // Configure the edge node to connect to the data source only when the producer is online. You can test it out
            // e.g. by stopping or disconnecting from the MQTT broker.
            //
            // You can compare the output of this example with and without the statement below. With the statement, the
            // Poll event will not be raised unless the producer is online. Without the statement, the Poll event will
            // always be raised while the edge node is started, regardless of the MQTT broker connection state.
            edgeNode.DataSourceConnectionMode = SparkplugDataSourceConnectionMode.WhenProducerOnline;

            // Hook the SystemConnectionStateChanged event to handle system connection state changes.
            edgeNode.SystemConnectionStateChanged += (sender, eventArgs) =>
            {
                // Display the new connection state (such as when the connection to the broker succeeds or fails).
                Console.WriteLine($"{nameof(EasySparkplugEdgeNode.SystemConnectionStateChanged)}: {eventArgs}");
            };

            // Hook the ProducerOnlineChanged event to handle changes in the online state of the producer.
            edgeNode.ProducerOnlineChanged += (sender, eventArgs) =>
            {
                // Display the new producer online state.
                Console.WriteLine($"{nameof(EasySparkplugEdgeNode.ProducerOnlineChanged)}: {edgeNode.ProducerOnline}");
            };

            // Hook the Poll event (but do not mark the polling as processed by ourselves).
            edgeNode.Poll += (sender, eventArgs) =>
            {
                // Display when the component is polling for new data.
                Console.WriteLine(nameof(EasySparkplugEdgeNode.Poll));
            };

            // Define a metric providing random integers.
            var random = new Random();
            edgeNode.Metrics.Add(new SparkplugMetric("MyMetric").ReadValueFunction(() => random.Next()));

            // Start the edge node.
            Console.WriteLine("The edge node is starting...");
            edgeNode.Start();

            Console.WriteLine("The edge node is started.");
            Console.WriteLine();

            // Let the user decide when to stop.
            Console.WriteLine("Press Enter to stop the edge node...");
            Console.ReadLine();

            // Stop the edge node.
            Console.WriteLine("The edge node is stopping...");
            edgeNode.Stop();

            Console.WriteLine("The edge node is stopped.");
        }
    }
}

' This example shows how to connect to the data source only when the producer is online.
'
' You can use any Sparkplug application, including our SparkplugCmd utility and the SparkplugApplicationConsoleDemo
' program, to subscribe to the edge node data.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
' Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-CSharp .
' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
' a commercial license in order to use Online Forums, and we reply to every post.

Imports OpcLabs.EasySparkplug

Namespace Global.SparkplugDocExamples.EdgeNode._EasySparkplugEdgeNode
    Class DataSourceConnectionMode
        Public Shared Sub Main1()
            ' Note that the default port for the "mqtt" scheme is 1883.
            Dim hostDescriptor = New SparkplugHostDescriptor("mqtt://localhost")

            ' Instantiate the edge node object.
            Dim edgeNode = New EasySparkplugEdgeNode(hostDescriptor, "easyGroup", "easySparkplugDemo")

            ' Configure the edge node to connect to the data source only when the producer is online. You can test it out
            ' e.g. by stopping or disconnecting from the MQTT broker.
            ' 
            ' You can compare the output of this example with and without the statement below. With the statement, the
            ' Poll event will not be raised unless the producer is online. Without the statement, the Poll event will
            ' always be raised while the edge node is started, regardless of the MQTT broker connection state.
            edgeNode.DataSourceConnectionMode = SparkplugDataSourceConnectionMode.WhenProducerOnline

            ' Hook the SystemConnectionStateChanged event to handle system connection state changes.
            AddHandler edgeNode.SystemConnectionStateChanged,
                Sub(sender, eventArgs)
                    ' Display the new connection state (such as when the connection to the broker succeeds or fails).
                    Console.WriteLine($"{NameOf(EasySparkplugEdgeNode.SystemConnectionStateChanged)}: {eventArgs}")
                End Sub

            ' Hook the ProducerOnlineChanged event to handle changes in the online state of the producer.
            AddHandler edgeNode.ProducerOnlineChanged,
                Sub(sender, eventArgs)
                    ' Display the new producer online state.
                    Console.WriteLine($"{NameOf(EasySparkplugEdgeNode.ProducerOnlineChanged)}: {edgeNode.ProducerOnline}")
                End Sub

            ' Hook the Poll event (but do not mark the polling as processed by ourselves).
            AddHandler edgeNode.Poll,
                Sub(sender, eventArgs)
                    ' Display when the component Is polling for New data.
                    Console.WriteLine(NameOf(EasySparkplugEdgeNode.Poll))
                End Sub

            ' Define a metric providing random integers.
            Dim random = New Random()
            edgeNode.Metrics.Add(New SparkplugMetric("MyMetric").ReadValueFunction(Function() random.Next()))

            ' Start the edge node.
            Console.WriteLine("The edge node is starting...")
            edgeNode.Start()

            Console.WriteLine("The edge node is started.")
            Console.WriteLine()

            ' Let the user decide when to stop.
            Console.WriteLine("Press Enter to stop the edge node...")
            Console.ReadLine()

            ' Stop the edge node.
            Console.WriteLine("The edge node is stopping...")
            edgeNode.Stop()

            Console.WriteLine("The edge node is stopped.")
        End Sub
    End Class
End Namespace

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

Reference

ISparkplugProducer Interface
ISparkplugProducer Members
WhenProducerOnline Field

Documentation Home, Send Feedback. Resources: Knowledge Base, Product Downloads. Technical support: Online Forums, FAQ.

Missing some example? Ask us for it on our Online Forums! You do not have to own a commercial license in order to use Online Forums, and we reply to every post.