Make common cache typed with generics (#2896)

Making typed common cache so that we don't use wrong types
across set/get methods and more higher-level methods can be
defined for cache.
Currently, we are not able to operate over all keys of the cache
due to generic types.
I also removed code comments around the cache.

Signed-off-by: Sanket Sudake <sanketsudake@gmail.com>

pkg/router/functionReferenceResolver.go

@@ -34,7 +34,7 @@ type (
 	// reference into a resolveResult
 	functionReferenceResolver struct {
 		// FunctionReference -> function metadata
-		refCache     *cache.Cache
+		refCache     *cache.Cache[namespacedTriggerReference, resolveResult]
 		funcInformer map[string]k8sCache.SharedIndexInformer
 		logger       *zap.Logger
 		// store    k8sCache.Store
@@ -73,7 +73,7 @@ const (
 
 func makeFunctionReferenceResolver(logger *zap.Logger, funcInformer map[string]k8sCache.SharedIndexInformer) *functionReferenceResolver {
 	frr := &functionReferenceResolver{
-		refCache:     cache.MakeCache(time.Minute, 0),
+		refCache:     cache.MakeCache[namespacedTriggerReference, resolveResult](time.Minute, 0),
 		funcInformer: funcInformer,
 		logger:       logger.Named("function_ref_resolver"),
 	}
@@ -89,9 +89,8 @@ func (frr *functionReferenceResolver) resolve(trigger fv1.HTTPTrigger) (*resolve
 	}
 
 	// check cache
-	rrInt, err := frr.refCache.Get(nfr)
+	result, err := frr.refCache.Get(nfr)
 	if err == nil {
-		result := rrInt.(resolveResult)
 		return &result, nil
 	}
 
@@ -216,11 +215,5 @@ func (frr *functionReferenceResolver) delete(namespace string, triggerName, trig
 }
 
 func (frr *functionReferenceResolver) copy() map[namespacedTriggerReference]resolveResult {
-	cache := make(map[namespacedTriggerReference]resolveResult)
-	for k, v := range frr.refCache.Copy() {
-		key := k.(namespacedTriggerReference)
-		val := v.(resolveResult)
-		cache[key] = val
-	}
-	return cache
+	return frr.refCache.Copy()
 }

pkg/router/functionServiceMap.go

@@ -29,7 +29,7 @@ import (
 type (
 	functionServiceMap struct {
 		logger *zap.Logger
-		cache  *cache.Cache // map[metadataKey]*url.URL
+		cache  *cache.Cache[metadataKey, *url.URL]
 	}
 
 	// metav1.ObjectMeta is not hashable, so we make a hashable copy
@@ -44,7 +44,7 @@ type (
 func makeFunctionServiceMap(logger *zap.Logger, expiry time.Duration) *functionServiceMap {
 	return &functionServiceMap{
 		logger: logger.Named("function_service_map"),
-		cache:  cache.MakeCache(expiry, 0),
+		cache:  cache.MakeCache[metadataKey, *url.URL](expiry, 0),
 	}
 }
 
@@ -62,15 +62,14 @@ func (fmap *functionServiceMap) lookup(f *metav1.ObjectMeta) (*url.URL, error) {
 	if err != nil {
 		return nil, err
 	}
-	u := item.(*url.URL)
-	return u, nil
+	return item, nil
 }
 
 func (fmap *functionServiceMap) assign(f *metav1.ObjectMeta, serviceURL *url.URL) {
 	mk := keyFromMetadata(f)
 	old, err := fmap.cache.Set(*mk, serviceURL)
 	if err != nil {
-		if *serviceURL == *(old.(*url.URL)) {
+		if *serviceURL == *old {
 			return
 		}
 		fmap.logger.Error("error caching service url for function with a different value", zap.Error(err))