Previously the SupportsBlocking option was specified by a method on the
type, and all the other options were specified from RegisterOptions.
This change moves RegisterOptions to a method on the type, and moves
SupportsBlocking into the options struct.
Currently there are only 2 cache-types. So all cache-types can implement
this method by embedding a struct with those predefined values. In the
future if a cache type needs to be registered more than once with different
options it can remove the embedded type and implement the method in a way
that allows for paramaterization.
Fixes#6521
Ensure that initial failures to fetch an agent cache entry using the
notify API where the underlying RPC returns a synthetic index of 1
correctly recovers when those RPCs resume working.
The bug in the Cache.notifyBlockingQuery used to incorrectly "fix" the
index for the next query from 0 to 1 for all queries, when it should
have not done so for queries that errored.
Also fixed some things that made debugging difficult:
- config entry read/list endpoints send back QueryMeta headers
- xds event loops don't swallow the cache notification errors
Fixes#4969
This implements non-blocking request polling at the cache layer which is currently only used for prepared queries. Additionally this enables the proxycfg manager to poll prepared queries for use in envoy proxy upstreams.
