## Problem
part of https://github.com/neondatabase/neon/issues/11813
## Summary of changes
It costs $$$ to directly retrieve the feature flags from the pageserver.
Therefore, this patch adds new APIs to retrieve the spec from the
storcon and updates it via pageserver.
* Storcon retrieves the feature flag and send it to the pageservers.
* If the feature flag gets updated outside of the normal refresh loop of
the pageserver, pageserver won't fetch the flags on its own as long as
the last updated time <= refresh_period.
Signed-off-by: Alex Chi Z <chi@neon.tech>
The 1.88.0 stable release is near (this Thursday). We'd like to fix most
warnings beforehand so that the compiler upgrade doesn't require
approval from too many teams.
This is therefore a preparation PR (like similar PRs before it).
There is a lot of changes for this release, mostly because the
`uninlined_format_args` lint has been added to the `style` lint group.
One can read more about the lint
[here](https://rust-lang.github.io/rust-clippy/master/#/uninlined_format_args).
The PR is the result of `cargo +beta clippy --fix` and `cargo fmt`. One
remaining warning is left for the proxy team.
---------
Co-authored-by: Conrad Ludgate <conrad@neon.tech>
## Problem
Part of #11813
## Summary of changes
The current interval is 30s and it costs a lot of $$$. 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 #11813
PostHog has two endpoints to retrieve feature flags: the old project ID
one that uses personal API token, and the new one using a special
feature flag secure token that can only retrieve feature flag. The new
API I added in this patch is not documented in the PostHog API doc but
it's used in their Python SDK.
## Summary of changes
Add support for "feature flag secure token API". The API has no way of
providing a project ID so we verify if the retrieved spec is consistent
with the project ID specified by comparing the `team_id` field.
---------
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>
## Problem
part of https://github.com/neondatabase/neon/issues/11813
## Summary of changes
Add a lite PostHog client that only uses the local flag evaluation
functionality. Added a test case that parses an example feature flag and
gets the evaluation result.
TODO: support boolean flag, remote config; implement all operators in
PostHog.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
