fix: prevent xdsIR updates from overwriting RateLimit configs from ot…

…her xdsIR

Signed-off-by: Kensei Nakada <[email protected]>

internal/globalratelimit/runner/runner.go

@@ -31,6 +31,7 @@ import (
 	"github.com/envoyproxy/gateway/internal/message"
 	"github.com/envoyproxy/gateway/internal/xds/translator"
 	"github.com/envoyproxy/gateway/internal/xds/types"
+	cacheTypes "github.com/envoyproxy/go-control-plane/pkg/cache/types"
 )
 
 const (
@@ -110,6 +111,9 @@ func (r *Runner) serveXdsConfigServer(ctx context.Context) {
 }
 
 func (r *Runner) subscribeAndTranslate(ctx context.Context) {
+	// rateLimitConfigsCache is a cache of the rate limit config, which is keyed by the xdsIR key.
+	rateLimitConfigsCache := map[string][]cacheTypes.Resource{}
+
 	// Subscribe to resources.
 	message.HandleSubscription(message.Metadata{Runner: string(egv1a1.LogComponentGlobalRateLimitRunner), Message: "xds-ir"}, r.XdsIR.Subscribe(ctx),
 		func(update message.Update[string, *ir.Xds], errChan chan error) {
@@ -120,6 +124,7 @@ func (r *Runner) subscribeAndTranslate(ctx context.Context) {
 					r.Logger.Error(err, "failed to update the config snapshot")
 					errChan <- err
 				}
+				delete(rateLimitConfigsCache, update.Key)
 			} else {
 				// Translate to ratelimit xDS Config.
 				rvt, err := r.translate(update.Value)
@@ -129,7 +134,14 @@ func (r *Runner) subscribeAndTranslate(ctx context.Context) {
 
 				// Update ratelimit xDS config cache.
 				if rvt != nil {
-					r.updateSnapshot(ctx, rvt.XdsResources)
+					// Build XdsResources to use for the snapshot update from the cache.
+					xdsResourcesToUpdate := types.XdsResources{}
+					rateLimitConfigsCache[update.Key] = rvt.XdsResources[resourcev3.RateLimitConfigType]
+					for _, xdsR := range rateLimitConfigsCache {
+						xdsResourcesToUpdate[resourcev3.RateLimitConfigType] = append(xdsResourcesToUpdate[resourcev3.RateLimitConfigType], xdsR...)
+					}
+
+					r.updateSnapshot(ctx, xdsResourcesToUpdate)
 				}
 			}
 		},