Managing shared parameters across multiple apps

[benmccallum]

Hi,

We have a situation where we have many apps, but some shared sets of configuration, say the config for a particular feature that app a and app b both use. Ideally we could share the config across apps, as it's be easier if we had to roll a secret or something.

Originally we started to structure our paths in Param Store such that we'd:

• load /all/* (for every app)
• load /app-x/* (where x is the current app)

For a shared feature config, this means logically we'd put that in say /all/feat-foo, but if there's then an app c which shouldn't have access to that feature's config (because it's highly sensitive and we want to limit its visibility), we now have an issue because it'll be visible to app c which has loaded /all/*.

We explored using policies so that /all/feat-foo was restricted for reads to apps a and b. The problem then is when app c starts up and can't read it feat-foo, it will blow up during startup.

So now we've moved to organising param paths by feature so that an app calls AddSystemManager once per feature. As we expand features my concern is now that this might have a performance drag on our app given so many config providers.

So I guess I'm wondering:

• should I be worried about a perf drain when I've added say 20 AWS config providers on various paths?
• are there any suggested patterns around this?

It's almost like Param Store needs this shared config concept supported more natively, one global config, then in each app path it's a virtual reference to the shared one to opt-in that app to receive that config.

Thanks in advance for any wisdom anyone can impart :)