UaException: message size exceeds configured limit

Ignition
1

Hi all,
Im trying to write a large string into the value of a memory tag via a golang opcua client.

        clientOption = append(clientOption, opcua.MaxMessageSize(33554432))
	clientOption = append(clientOption, opcua.SendBufferSize(uint32(50000)))
	clientOption = append(clientOption, opcua.ReceiveBufferSize(uint32(50000)))
	clientOption = append(clientOption, opcua.MaxChunkCount(0))

	opcuaClient, err := opcua.NewClient(serverEndpoint.EndpointURL, clientOption...)
	if err != nil {
		log.Info().Msg("error creating client: " + err.Error())
		return nil, err
	}

In the client i set a SendBufferSize parameter as well as a unlimited maxMessageSize. My issue is that whenever trying to write my string, i get this error in the ignition web console logs:

org.eclipse.milo.opcua.stack.core.channel.MessageDecodeException: UaException: status=Bad_TcpMessageTooLarge, message=message size exceeds configured limit: 3141728 > 2097152

at org.eclipse.milo.opcua.stack.core.channel.ChunkDecoder.decode(ChunkDecoder.java:97)

at org.eclipse.milo.opcua.stack.core.channel.ChunkDecoder.decodeSymmetric(ChunkDecoder.java:77)

at org.eclipse.milo.opcua.stack.server.transport.uasc.UascServerSymmetricHandler.lambda$onSecureMessage$1(UascServerSymmetricHandler.java:139)

at org.eclipse.milo.opcua.stack.core.channel.SerializationQueue.lambda$decode$1(SerializationQueue.java:63)

at org.eclipse.milo.opcua.stack.core.util.TaskQueue$TaskWrapper.run(TaskQueue.java:273)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

at java.base/java.lang.Thread.run(Unknown Source)

Caused by: org.eclipse.milo.opcua.stack.core.UaException: message size exceeds configured limit: 3141728 > 2097152

at org.eclipse.milo.opcua.stack.core.channel.ChunkDecoder$AbstractDecoder.decode(ChunkDecoder.java:241)

at org.eclipse.milo.opcua.stack.core.channel.ChunkDecoder.decode(ChunkDecoder.java:89)

... 7 common frames omitted

The UaException indicates a default max message size of 2097152. However when looking at the settings, i see that there is a parameter Max Message Size set to 33554432. I was confused since my string size (3141728 ) is way lower.

Screenshot 2024-03-25 144940
Screenshot 2024-03-25 144940875×915 30.6 KB

i digged a bit further and found out that the ignition opcua server is based on the [this]( milo/opc-ua-stack/stack-core/src/main/java/org/eclipse/milo/opcua/stack/core/channel/EncodingLimits.java at cd0f3d97f78de3823541229032642f8af9f00040 · eclipse/milo · GitHub
i can see that the default max message size is : 2 * 1024 *1024 = 2097152

so i was wondering if there was a way to increase this limit since the settings in the web console don't seem to affect this.

Thank you for your help.

2

There is not. The settings you are changing are for whatever OPC UA client connection you edited, they are not for the Ignition OPC UA server itself.

Maybe there's another approach to your problem that doesn't involve writing a 3MB string to a tag?

1 Like
3

Wow ! Thanks for the quick reply. It sure saves me a lot of googling :smile:

Maybe i'll try to split the payload and send it in a sequence and use opcua subscription to know when to send the next sequence.

Thanks again for the quick reply.