decision(storage-resize-images): kit/extension parity – event source is per function, not per instance #3272

storage-resize-images kit/extension parity. Priority: low. A subscriber that filters on the extension's source receives nothing from the kit.

Difference

• Extension: source is //firebaseextensions.googleapis.com/extensions/projects/<project>/instances/<instance>.
• Kit: source is projects/<project>/locations/<region>/services/kit-<instance>-generateResizedImage.

On a shared channel, source is the only attribute that tells instances apart.

Reproduced

Captured from both sides on the default channel with a run-scoped subscriber function; every kit event had the service-based source.

Code

• Kit: no source is set, so the Eventarc client's default is used (events.ts#L27-L49).

Resolution

Two options:

• Set source to a stable per-instance value.
• Keep it and record it as an accepted difference under "Decisions", with a note in the README's Events section. decision(delete-user-data): kit/extension parity – event source is per function, not per instance #3255 raises the same question for delete-user-data.