cache: add prefix/glob watch support to LinearCache for LEDS#1411
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wdauchy wants to merge 1 commit intoenvoyproxy:mainfrom
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cache: add prefix/glob watch support to LinearCache for LEDS#1411wdauchy wants to merge 1 commit intoenvoyproxy:mainfrom
wdauchy wants to merge 1 commit intoenvoyproxy:mainfrom
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Envoy's LEDS uses delta xDS with glob collection subscriptions where clients subscribe to resource names ending in /* (e.g. ns_svc_8080/us-east-1a/*) and expect to receive all individual resources whose name starts with that prefix. Currently LinearCache only supports exact-name watches and full wildcard watches. A subscription to collection/* is stored as a literal key in resourceWatches and never matches individual resources under that prefix. Add a new prefixWatches map to LinearCache that is keyed by the prefix (with trailing * stripped, keeping the separator). When a subscribed resource name ends with /*, the watch is registered in prefixWatches instead of resourceWatches. notifyAll iterates prefixWatches for each modified resource and triggers matching prefix watches. computeResourceChange expands prefix subscriptions to all matching resources in the cache, detecting new, updated, and deleted resources under the prefix. Signed-off-by: William Dauchy <[email protected]> Co-authored-by: Cursor <[email protected]>
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fyi I started to merge this on Datadog production to see how far we can go with it
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Envoy's LEDS (Locality Endpoint Discovery Service) uses delta xDS with
glob collection subscriptions. Clients subscribe to resource names ending
in
/*(e.g.ns_svc_8080/us-east-1a/*) viaresource_names_subscribein
DeltaDiscoveryRequest, and expect to receive all individual resourceswhose name starts with that prefix.
Currently
LinearCacheonly supports exact-name watches (resourceWatches)and full wildcard (
wildcardWatches). A subscription tocollection/*isstored as a literal key in
resourceWatchesand never matches individualresources under that prefix.
This PR adds a
prefixWatchesmap toLinearCachethat handles globsubscriptions:
trackWatch: when a subscribed resource name ends with/*, thewatch is registered in
prefixWatches[prefix]instead ofresourceWatches[name]notifyAll: iteratesprefixWatchesfor each modified resource andtriggers matching prefix watches
computeResourceChange: expands prefix subscriptions to all matchingresources in the cache, detecting new, updated, and deleted resources
under the prefix
computeResponse: expands prefix globs in the full-state non-wildcardbranch
prefixWatchesentriesExisting exact-name and wildcard behavior is unchanged.