Document Kubernetes Kit backend session expiration policy

[TatuLund]

See: https://github.com/vaadin/kubernetes-kit/pull/163/files

[mcollovati]

By implementing the SessionExpirationPolicy interface, the developer can define the expiration timeout.
However, the property does not define the timeout value, but the amount of time to be added to the HTTP session timeout to determine the expiration of the backend session. If time unit is not given, milliseconds is assumed.

[mcollovati]

It would be nice to add also a SessionExpirationPolicy implementation example

[TatuLund]

Thanks for clarification

[TatuLund]

Should this suffice for code example?

    @Bean
    SessionExpirationPolicy sessionExpirationPolicy() {
        return Duration.ofMinutes(60);
    }

[mcollovati]

The SessionExpirationPolicy.apply() method takes current HTTP session timeout as argument

@Bean
SessionExpirationPolicy sessionExpirationPolicy() {
    return sessionTimeout -> Duration.ofMinutes(60);
}

[MatthewVaadin]

If time unit is not given, milliseconds is assumed.

This may be the default, but it's not particularly useful. If seconds are more appropriate, perhaps the property should be annotated with @DurationUnit(ChronoUnit.SECONDS) and the original phrasing kept?

[mcollovati]

Sound a good idea

[jorgheymans]

Are these docs scheduled for publishing anytime soon ?

[github-actions]

AI Language Review

The newly added section on "Backend Session Expiration Policy" is clear and well-structured. The example code is correctly formatted, and the explanation is understandable. There are no issues requiring improvement.

[mcollovati]

@MatthewVaadin do you think it is ok to merge?

[MatthewVaadin]

I'm still concerned that we don't have consistency across the examples, or an explanation that the Java example works differently than the other two. In my "resolved" review I proposed a fix that already included the corrected spelling mistake, along with a layout that allows a description for each example without resorting to in-example comments.