link discrepancy between GDC and GC

[tomkralidis]

As per https://wmo-im.github.io/wis2-guide/guide/wis2-guide-DRAFT.html#_global_discovery_catalogue:

A Global Discovery Catalogue will only update discovery metadata records to replace links for dataset subscription and notification (origin) with their equivalent links for subscription at Global Broker instances (cache).

...given the lifecycle of a WCMP2 record:

• WIS2 Node publishes WNM pointing to WCMP2 record
• GB receives message
• GC (subscribed to GC) stores WCMP2 record to cache
• GDC (subscribed to GB) detects (via origin/a/wis2/+/metadata/#)
• GDC downloads from GC
• GDC updates links of GB and GC
• GDC publishes updated record to its OGC API - Records API

The GC still has the original WCMP2 document with the original subscription/notification links, given the changes the GDC made to the WCMP2 document were not propagated back to the GC.

Options:

1. have GDC notify on the updated WCMP2 record (topic TBD) so GC can update
2. other options?

cc @antje-s @6a6d74 @golfvert

[antje-s]

#53