The core quamina.Matcher doesn't currently support deleting patterns. Some of the contemplated implementations would probably be pretty difficult. At least one approach is pretty easy: Wrap the current matcher to filter removed patterns from match results and periodically rebuild the matcher from scrach with the live patterns. More specifically:
- Remember patterns that have been added
- Remember patterns that have been removed (implicitly)
- Filter
MatchesFor...()results to remove any removed patterns - Rebuilding the matcher state periodically with only the live patterns
- Maintain some statistics to help decide when to rebuild
The implementation of the set of live patterns is pluggable via a Go
interface (State). The default implementation MemState is just a
map[quamina.X]string. Other implementations could provide
persistence.
By default, rebuilding is triggered automatically (synchronously
currently) during mutations. You can also force a manual Rebuild(),
and you can DisableRebuild() to prevent any automation rebuilds.
The code also supports pluggable rebuilding policies, but those
features are not currently exposed.