[plugins] Log warnings from core in dev mode when setup contracts are called after start.

[lukeelmers]

There are many places in Kibana where we find plugins abusing lifecycle methods by doing things like holding references to dependencies from the setup contract, and then using that dependency later during the start lifecycle.

While some of these abuses are relatively harmless, it can create much more serious problems in the case of things like registries: If a plugin holds a reference to a registry from setup, and then registers an item to it during start, plugins can no longer be assured that the registry is fully populated by the time we reach start... thus breaking the guarantees lifecycles were designed to provide.

There are some places in core where we have put safeguards in place to prevent such behavior:

kibana/src/core/server/saved_objects/saved_objects_service.ts

Lines 374 to 377 in ca05637

	registerType: (type) => {
	if (this.started) {
	throw new Error('cannot call `registerType` after service startup.');
	}

However, the only way to have this be completely bulletproof would be for every plugin exposing public registries to apply similar safeguards. A much simpler way to start would be by simply logging a warning while in dev mode if we detect a plugin calling any setup contracts after start has begun.

Tasks

• Wrap every lifecycle API from core, and perform a check to see if the cycle is active
• If setup API has been called in start or stop, and we are in dev mode, log a warning
• If start API has been called in stop, and we are in dev mode, log a warning

---

cc @stacey-gammon

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[Dosant]

Since ideally we also need this for each plugin, I am curious if you plan to:

1. have a one-off core internal solution for now,
2. or if core would also automatically handle this for all the plugins. (proxying/wrapping each plugin's contract?)
3. or have a shared utility that plugins can use to wrap their setup contracts that will track when something is accessed

[pgayvallet]

I would love to have a generic wrapping solution to be honest, either automatically performed inside core, or exposed as an utility for plugins to use, as adding an explicit check, or manually wrapping all APIs will be way too verbose.

However, given the nested (and sometime dynamic) nature of core's and our plugins' lifecycle contracts, I'm not 100% sure this can easily be performed automatically, unless we implement some kind of deep proxy wrapping.

e.g

setup(core) {
   this.deepRef = core.someService.someRegistry
}

start() {
   this.deepRef.shouldntBeCallingThatDuringStart()
}

Would not be caught by a basic proxy approach wrapping either coreSetup or even each individual service.

Also note that for performances reasons, we probably want to perform this wrapping only in dev mode (silencing the warning in prod is not good enough).

[Dosant]

unless we implement some kind of deep proxy wrapping.
we probably want to perform this wrapping only in dev mode

Maybe if we indeed do it only in dev mode and exclude performance concerns, then deep proxy does make sense and is doable here