alt Hacker NewsThe end here reminds me of "The Log: Real-time data's unifying abstraction" [0], which has unfortunately had a bit of link-rot since 2013.
One complication in this approach involves access-windows: What if my system is only supposed to be seeing stuff that happened during two separate weeks in the year, because those are the spans when it was subscribed or authorized?
So the data-host would need to maintain a concept of "connection history" for other services, and also use that to filter/modify its real event stream, inserting artificial "initial state" roll-ups of events that happened in dark periods.
That requirement seems ... uncommon. How many systems/industries have a frequent notion of transient/sliced views of history for their customers?
If that is a real requirement, it seems like it'd be easier to meet by giving customers a realtime-stream/log API whose history starts when they were most recently granted access, and providing them older historical events via a separate API of the classic "ask for a report and we'll get back to you within a day or two with an S3 presigned URL" variety, then synthesizing that huge historical report in batch code that's aware of the subtleties of the customer's visibility windows.