Design

This page goes into some of the design particulars of Kele. As an end user, feel free to explore at your curiosity, but rest assured that none of the information here is strictly necessary for your successful use of Kele.

Tip

This page may at times contain forward-looking statements, e.g. of design details that are upcoming but have not yet made their way into the main branch.

Caches

Kele revolves around two main in-memory caches:

• One that maintains the kubeconfig contents (kele--kubeconfig);
• One that maintains the discovery cache in-memory (kele--discovery-cache).

Both of these caches are populated asynchronously on kele-mode initialization.

The kubeconfig cache is kept in sync via a file watcher, which allows Kele to only incur read costs when they’re actually needed. This is particularly useful for the kubeconfig cache, since the Kubeconfig itself is only occasionally modified in response to discrete user events, such as switching context or the default namespace for a given context. In combination with asynchronous IO via the async package, Kele is able to keep itself in sync with the underlying Kube configurations and caches without deadlocking users’ Emacs environment.

On the other hand, the discovery cache is timer-based and pulls the contents of the discovery cache from the filesystem at a set interval, as dictated by kele-discovery-refresh-interval.

Why?

We elect not to use file-watchers for the discovery cache due to the risk of completely exhausting the file descriptors Emacs can use. For more details, see adr-01.