## Problem
part of https://github.com/neondatabase/neon/issues/11813
## Summary of changes
It costs $$$ to directly retrieve the feature flags from the pageserver.
Therefore, this patch adds new APIs to retrieve the spec from the
storcon and updates it via pageserver.
* Storcon retrieves the feature flag and send it to the pageservers.
* If the feature flag gets updated outside of the normal refresh loop of
the pageserver, pageserver won't fetch the flags on its own as long as
the last updated time <= refresh_period.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Part of #11813
## Summary of changes
Add a test API to make it easier to manipulate the feature flags within
tests.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Part of #11813
## Summary of changes
The current interval is 30s and it costs a lot of $$$. This patch
reduced it to 600s refresh interval (which means that it takes 10min for
feature flags to propagate from UI to the pageserver). In the future we
can let storcon retrieve the feature flags and push it to pageservers.
We can consider creating a new release or we can postpone this to the
week after the next week.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
part of https://github.com/neondatabase/neon/issues/11813
## Summary of changes
Collect pageserver hostname property so that we can use it in the
PostHog UI. Not sure if this is the best way to do that -- open to
suggestions.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Part of https://github.com/neondatabase/neon/issues/11813
In PostHog UI, we need to create the properties before using them as a
filter. We report all variants automatically when we start the
pageserver. In the future, we can report all real tenants instead of
fake tenants (we do that now to save money + we don't need real tenants
in the UI).
## Summary of changes
* Collect `region`, `availability_zone`, `pageserver_id` properties and
use them in the feature evaluation.
* Report 10 fake tenants on each pageserver startup.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Part of https://github.com/neondatabase/neon/issues/11813
## Summary of changes
Add a counter on the feature evaluation outcome and we will set up
alerts for too many failed evaluations in the future.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Part of #11813. This pull request adds misc observability improvements
for the functionality.
## Summary of changes
* Info span for the PostHog feature background loop.
* New evaluate feature flag API.
* Put the request error into the error message.
* Log when feature flag gets updated.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Part of https://github.com/neondatabase/neon/issues/11813
## Summary of changes
* Support evaluate boolean flags.
* Add docs on how to handle errors.
* Add test cases based on real PostHog config.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
part of https://github.com/neondatabase/neon/issues/11813
## Summary of changes
* Integrate feature store with tenant structure.
* gc-compaction picks up the current strategy from the feature store.
* We only log them for now for testing purpose. They will not be used
until we have more patches to support different strategies defined in
PostHog.
* We don't support property-based evaulation for now; it will be
implemented later.
* Evaluating result of the feature flag is not cached -- it's not
efficient and cannot be used on hot path right now.
* We don't report the evaluation result back to PostHog right now.
I plan to enable it in staging once we get the patch merged.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
