Licensing: allow multiple registration of the same feature

[pgayvallet]

Summary

Adapt the FeatureUsage service to accept multiple registrations of the same feature, as long as the licenseType is the same.

This is driven by the fact that features can now be registered from the client-side, so every refresh or new client can call this API, resulting in multiple calls.

Checklist

• Unit or functional tests were updated or added to match the most common scenarios

[pgayvallet]

@restrry This is the easiest fix for the problem, and answer the need.

Another option would be to instead adapt the client-side service to fetch the list of already registered features from the server-side during setup and to not perform calls to the server when trying to register an already existing feature. This is just a little trickier if we want to keep the client-side service synchronous

kibana/x-pack/plugins/licensing/public/services/feature_usage_service.ts

Lines 41 to 53 in 5f781dc

	export class FeatureUsageService {
	public setup({ http }: SetupDeps): FeatureUsageServiceSetup {
	return {
	register: async (featureName, licenseType) => {
	await http.post('/internal/licensing/feature_usage/register', {
	body: JSON.stringify({
	featureName,
	licenseType,
	}),
	});
	},
	};
	}

as it would mean creating the fetch promise during setup and await for its result in every call to register. But nothing that can't be done. Do you think this would be better?

[joshdover]

I like the solution you have in PR. It's simpler and less likely to break IMO.

[Dosant]

Other option could be to allow multiple registerFeature calls from client side, but leave validation for server side api?
Could we check inside route handler if featureName already registered? If yes, then respond 200, if no, then register and respond 200.

[pgayvallet]

Yea, that would be another possibility

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: f74f1b9

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[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[joshdover]

I like the solution you have in PR. It's simpler and less likely to break IMO.