add "is_running(service)" to Container

To check if a service is running we need to:

self.container.get_service("service_name").is_running()

Recently Container.restart(services) was added and Container.is_running(service) would be a great companion.

[rbarry82]

ops.pebble is explicitly part of the operator framework.

ops.model and ops.framework wrap a fair amount of things. It isn’t necessarily about talking to pebble directly (which container.get_service("service_name").is_running() is not doing either, by the way), and more about encapsulation.

ops.pebble.Service is the representation get_service returns, and whether or not it’s running depends checks against ops.pebble.ServiceStatus.

Logically, a Container may have many services. is_running("service_name") reads akin to “each service has its own container”. If anything, Container.get_service_status("service") would make more sense, but then we’re simply re-exporting an enum from ops.pebble and re-implementing the same logic (either punting it to charm authors or moving it up a level and duplicating it in ops.model) unless it calls exactly the same code in your original comment, or self.get_service("service_name").is_running(), really.

[sed-i]

I do not recall encountering charm code that talks to pebble directly. To my understanding, ops.model servers as a wrapper around anything pebble (cf. container.pull).

It is true though that start, stop, restart all have the same “directionality” to them (OF -> Pebble).

A Container can have more than one service in a Pebble layer.

The container.is_running() interface could deal with that, e.g. if all/any(container.is_running(lst)) etc.