Are we supposed to be able to use getConfig inside instrumentation-client.ts?

[cupofjoakim]

Summary

Hi!

We're upgrading our setup from 15.2 to 15.5, and with that came a bunch of changes needed for our Sentry setup.

Now that we have moved our setup into instrumentation-client.ts, we get hit with an issue. The runtime configuration variables we've previously relied on seem to not be readable.

Running getConfig() always seem to return undefined inside this file.

I can't see any mention of this being the expected behaviour, so I wanted to check if that is what is expected or not.

Additional information

No response

Example

No response

[priyanshusinghchouhan]

Looks like this is expected behavior.
getConfig() only works in a server context, so when you call it from instrumentation-client.ts it’ll always return undefined. That file runs on the client side, so runtime config isn’t exposed there.
If you need to access config values for Sentry setup, you have two options:
=> Move that logic into instrumentation.ts (the server instrumentation file).
=> Or, if the values are safe to expose, put them in NEXT_PUBLIC_ env variables so they’re available on the client.

That should stop getConfig() from giving you undefined in the client instrumentation file.

[cupofjoakim]

So the publicRuntimeOptions that otherwise are accessible on the client and gotten from getConfig are not ok ro use here?

[priyanshusinghchouhan]

Exactly — publicRuntimeConfig isn’t available inside instrumentation-client.ts.
That file runs very early in the client lifecycle, so it won’t have access to runtime config.

If you need something client-side, the safe way is to move it into NEXT_PUBLIC_ env vars instead.
That way it’s directly exposed and won’t rely on getConfig().