Are node.wait()s automatically synced for pub and sub processes?

[kiasar]

Hi,
In the "Publish–Subscribe" article, the system is described and implemented like below. I have a question about the wait function.

For the publisher:

Larry isn’t exactly Formula 1 material, so publishing every 100 ms is plenty. We set up a loop, wait 100 ms, read the sensor, and send the data:
node.wait(iox2.Duration.from_millis(100))

For the subscriber:

Since the publisher sends updates every 100 ms, we loop at the same pace and check for new data. If we receive something, we print it:
node.wait(iox2.Duration.from_millis(100))

Here, there are two seperate wait function, one for the publisher and one for the subscriber. If the two wait function are not synced we can get up to 100ms latency, which means we can recive outdated data.
I just wanted to ask if these two wait function would be automatically synced, or they are just independent while loops?

If we want to immediately recive what the publisher has published, would this be the best practice?

[elBoberido]

@kiasar the node.wait call is just a convenient way to let the process sleep. It does not effect the communication.

With iceoryx2, we decoupled the data-flow from the control flow. Publish-Subscribe, Request-Response and Blackboard are data-flow pattern and are polling based. Events are a control flow pattern and can be used to block a thread.

If you do not want to do polling, you can combine one of the data-flow pattern with the Event and for example, use a Notifier to send an event each time a sample is published. But be aware, the internal buffer for events is limited, so you might see a warning about dropped events. This is not a problem as long as you use only one event-id, since the Listener is guaranteed to wake up when events start do drop. On the Listener side, you need to read all samples once there is an event. See also https://github.com/eclipse-iceoryx/iceoryx2/tree/main/examples/rust/event_based_communication

[kiasar]

Thanks for your answer Mathias. btw excellent project.