Observer list and status

[ch1bo]

Why

The explorer has multiple observers scanning the chain (on multiple networks). The user interface or API, however, does not provide any observability of that process. For example it is not clear which observers are currently online or whether the observer has already reached the tip or not.

What (TBD)

• Add an API endpoint that lists known /observers that contains information about the last processed block/slot of each observer
• Visualize in the last seen tick of an observer vs. other observers?

[ch1bo]

Related to this is also that the logs available on the explorer container are not indicating whether a head transaction was observed or only a new block (tick):

So maybe splitting the observer API into two routes could help in observability too?