pubsub connection does't support one-by-one establishment

[ReidLi]

If want to enable pubsub functionality, need add pubsub_module_init() into application code, it will read the default configuration binary file ‘pubsubconfig.uabinary’. While if we want to change the pubsub configuration dynamically, it seems the work flow is that pubsub stops with ‘pubsub_shutdown’, apply the new pubsub configuration, then pubsub starts with ‘pubsub_startup’. It means that if we want to add a new pubsub connection, other irrelevant connections will also stops, then all connections will restart after the new configuration is applied. It does not support one-by-one connection establishment.

For example, we may configure the pubsub function in below ‘Configuration_3’ in UaExpert and then ‘Transfer configuration to server’. After download, ‘Configuration_3’ will disappear, pubsub function will stop and restart. Do you have a plan to support one-by-one connection establishment so that we can add or delete one pubsub connection and other irrelevant pubsub connections will not be affected?


https://ibb.co/KsBWrJL

[Support Team]

Hi,

if we want to add a new pubsub connection, other irrelevant connections will also stops, then all connections will restart after the new configuration is applied.

Yes, that is correct! Any change in the PubSub-Configuration will stop/restart the complete stack. With that we ensure (in very simple fashion) the consistency across the whole configuration. In many use cases this behavior is sufficient, because an automation system typically does not frequently change it's own I/O devices or change it's own controlers. However, there might be use cases where more dynamic or "delta-change" in the configuration without restart (of existing connection) is desired.

In case of highly dynamic change in requested data and with highly flexible change in connections to devices/controllers/applications, you may re-consider your architecture and use "Client/Server" connection instead of PubSub.