* Fix race condition during a cache get
Check the entry we pulled out of the cache while holding the lock had Fetching set.
If it did then we should use the existing Waiter instead of calling fetch. The reason
this is better than just calling fetch is that fetch re-gets the entry out of the
entries map and the previous fetch may have finished. Therefore this prevents
erroneously starting a new fetch because we just missed the last update.
* Fix race condition fully
The first commit still allowed for the following scenario:
• No entry existing when checked in getWithIndex while holding the read lock
• Then by time we had reached fetch it had been created and finished.
* always use ok when returning
* comment mentioning the reading from entries.
* use cacheHit consistently
* Support rate limiting and concurrency limiting CSR requests on servers; handle CA rotations gracefully with jitter and backoff-on-rate-limit in client
* Add CSR rate limiting docs
* Fix config naming and add tests for new CA configs
* Add State storage and LastResult argument into Cache so that cache.Types can safely store additional data that is eventually expired.
* New Leaf cache type working and basic tests passing. TODO: more extensive testing for the Root change jitter across blocking requests, test concurrent fetches for different leaves interact nicely with rootsWatcher.
* Add multi-client and delayed rotation tests.
* Typos and cleanup error handling in roots watch
* Add comment about how the FetchResult can be used and change ca leaf state to use a non-pointer state.
* Plumb test override of root CA jitter through TestAgent so that tests are deterministic again!
* Fix failing config test
* Fixes#4480. Don't leave old errors around in cache that can be hit in specific circumstances.
* Move error reset to cover extreme edge case of nil Value, nil err Fetch
* Add cache types for catalog/services and health/services and basic test that caching works
* Support non-blocking cache types with Cache-Control semantics.
* Update API docs to include caching info for every endpoint.
* Comment updates per PR feedback.
* Add note on caching to the 10,000 foot view on the architecture page to make the new data path more clear.
* Document prepared query staleness quirk and force all background requests to AllowStale so we can spread service discovery load across servers.
* Fix theoretical cache collision bug if/when we use more cache types with same result type
* Generalized fix for blocking query handling when state store methods return zero index
* Refactor test retry to only affect CI
* Undo make file merge
* Add hint to error message returned to end-user requests if Connect is not enabled when they try to request cert
* Explicit error for Roots endpoint if connect is disabled
* Fix tests that were asserting old behaviour
Few other fixes in here just to get a clean run locally - they are all also fixed in other PRs but shouldn't conflict.
This should be robust to timing between goroutines now.
Matt Keeler