Plugins: Refactor kvstore usage in signing keys and angular patterns (#73154)

* Initial refactoring work for plugins kvstore

* Replace implementations for keystore and angularstore

* Cleanup

* add interface check

* lint

* fix storeKeyGetter not being called in namespacedstore set

* Fix tests

* Comments

* Add tests

* Fix invalid cap in ListKeys when store is empty

* Update docstrings

* Add setLastUpdatedOnDelete

* Renamed DefaultStoreKeyGetterFunc, add TestDefaultStoreKeyGetter

* Sort imports

* PR review: removed last_updated key

* PR review: Removed setLastUpdatedOnDelete

* Re-added relevant tests

* PR review: Removed SingleKeyStore

* PR review: Removed custom marshaling support

* Renamed marshaler.go to marshal.go

* PR review: removed unused interfaces

* PR review: Moved marshal into namespacedstore.go

* PR review: removed storekeygetter

* Removed unused file cachekvstore.go

* Renamed NamespacedStore to CacheKvStore

* removed todo

pkg/services/pluginsintegration/keystore/keystore.go

@@ -1,74 +1,25 @@
 package keystore
 
 import (
-	"context"
-	"fmt"
-	"time"
-
 	"github.com/grafana/grafana/pkg/infra/kvstore"
 	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/services/pluginsintegration/cachekvstore"
 )
 
 // Service is a service for storing and retrieving public keys.
 type Service struct {
-	kv *kvstore.NamespacedKVStore
+	*cachekvstore.CacheKvStore
 }
 
 const (
-	prefix         = "key-"
-	lastUpdatedKey = "last_updated"
+	namespace = "plugin.publickeys"
+	prefix    = "key-"
 )
 
 var _ plugins.KeyStore = (*Service)(nil)
 
 func ProvideService(kv kvstore.KVStore) *Service {
 	return &Service{
-		kv: kvstore.WithNamespace(kv, 0, "plugin.publickeys"),
+		CacheKvStore: cachekvstore.NewCacheKvStoreWithPrefix(kv, namespace, prefix),
 	}
 }
-
-func (s *Service) Get(ctx context.Context, key string) (string, bool, error) {
-	return s.kv.Get(ctx, prefix+key)
-}
-
-func (s *Service) Set(ctx context.Context, key string, value string) error {
-	return s.kv.Set(ctx, prefix+key, value)
-}
-
-func (s *Service) Del(ctx context.Context, key string) error {
-	return s.kv.Del(ctx, prefix+key)
-}
-
-func (s *Service) GetLastUpdated(ctx context.Context) (*time.Time, error) {
-	lastUpdated := &time.Time{}
-	if val, ok, err := s.kv.Get(ctx, lastUpdatedKey); err != nil {
-		return nil, fmt.Errorf("failed to get last updated time: %v", err)
-	} else if ok {
-		if parsed, err := time.Parse(time.RFC3339, val); err != nil {
-			return nil, fmt.Errorf("failed to parse last updated time: %v", err)
-		} else {
-			lastUpdated = &parsed
-		}
-	}
-	return lastUpdated, nil
-}
-
-func (s *Service) SetLastUpdated(ctx context.Context) error {
-	lastUpdated := time.Now()
-	if err := s.kv.Set(ctx, lastUpdatedKey, lastUpdated.Format(time.RFC3339)); err != nil {
-		return fmt.Errorf("failed to update last updated time: %v", err)
-	}
-	return nil
-}
-
-func (s *Service) ListKeys(ctx context.Context) ([]string, error) {
-	keys, err := s.kv.Keys(ctx, prefix)
-	if err != nil {
-		return nil, err
-	}
-	res := make([]string, 0, len(keys))
-	for _, key := range keys {
-		res = append(res, key.Key)
-	}
-	return res, nil
-}