Bjarne Boström said
Hi,

The tutorial was improved a bit in 4.5.8, but most likely still needs some improvements. I should note that so far we have pretty much only tested “static” configurations (so it is possible that the below would not work). PubSub is really new when compared to the rest of the SDK and we are just starting in integrating it to our own apps. Also it’s design does differ quite a lot, since I tried to avoid some problems we have elsewhere in the SDK (basically having most things immutable fixes a lot).

Anyway, the PubSubSystemConf is immutable by design, it cannot be changed (nor any part of it, recursively). You must pass a function to the PubSubSystem.updateConfiguration that will transform the old configuration to whatever you would like the new configuration to be. We will add more helper/builder methods in the future, but at the moment you would need to replace the dataset.  

Thank you for your input.

I have just tried implementing an update by passing a function to PubSubSystem.updateConfiguration that creates a new PubSubVariableDataSetConf which is then passed into oldConfig.withDataSetAddedOrReplaced. Through the debugger, it seems that the PubSubSystem is using the new PubSubVariableDataSetConf, but the the PubSubSystem doesn’t seem to be publishing any data on my specified data topic.

Things I have tried:

1. Adding a few nodes to the initial dataset, data is published on MQTT, replacing the original dataset with an empty dataset using PubSubSystemConf.withDataSetAddedOrReplaced. Expected: data to stop publishing, Actual: data is still published

2. Creating an empty initial dataset, no data is published on MQTT, replacing the original dataset with a new dataset with nodes using PubSubSystemConf.withDataSetAddedOrReplaced. Expected: data to start publishing, Actual: no data is published

After a few hours of trial and error, it seems that PubSubSystem.updateConfiguration has to be called twice for it to actually change the nodes in the VariableDataSet. I have no idea what the difference is but here is the code snippet that works for me:

pubSubSystem.updateConfiguration(oldConfig -> oldConfig.withDataSetRemoved(“ExampleDataset”));
pubSubSystem.updateConfiguration(oldConfig -> {
PubSubVariableDataSetConf newVariableDataSetConfig = getVariableDataSetConfig(“ExampleDataset”, listOfVariables, server.getNamespaceTable());
return oldConfig.withDataSetAddedOrReplaced(newVariableDataSetConfig);
});

I am unsure if it is intended, but chain calling pubSubSystem.withDataSetRemoved(“ExampleDataset”).withDataSetAddedOrReplaced(myNewVariableDataSetConfig) does not seem to work, however calling them in two separate PubSubSystem.updateConfiguration calls (one to remove, and one to add) seems to work.

Would appreciate there’s advice on if there is a better/ right way to do it.

Sidenote: is there a roadmap/ estimation for the release of the the rest of the OPCUA PubSub features? or maybe even feature parity with the V1.04 OPCUA spec?

Thank you!