snp: clear kds cache daily

go.mod

@@ -12,6 +12,7 @@ require (
 	gopkg.in/yaml.v2 v2.4.0
 	k8s.io/api v0.28.4
 	k8s.io/apimachinery v0.28.4
+	k8s.io/utils v0.0.0-20230406110748-d93618cff8a2
 )
 
 require (
@@ -38,7 +39,6 @@ require (
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/klog/v2 v2.100.1 // indirect
-	k8s.io/utils v0.0.0-20230406110748-d93618cff8a2 // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
 	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
 	sigs.k8s.io/yaml v1.3.0 // indirect

internal/attestation/snp/cachedClient.go

@@ -2,44 +2,54 @@ package snp
 
 import (
 	"log/slog"
+	"time"
 
 	"github.com/edgelesssys/nunki/internal/memstore"
 	"github.com/google/go-sev-guest/verify/trust"
+	"k8s.io/utils/clock"
 )
 
 type cachedKDSHTTPClient struct {
 	trust.HTTPSGetter
 	logger *slog.Logger
 
-	cache *memstore.Store[string, cacheEntry]
+	gcTicker clock.Ticker
+	cache    *memstore.Store[string, []byte]
 }
 
 func NewCachedKDSHTTPClient(log *slog.Logger) *cachedKDSHTTPClient {
 	trust.DefaultHTTPSGetter()
-	return &cachedKDSHTTPClient{
+
+	gc := clock.RealClock{}.NewTicker(24 * time.Hour)
+	c := &cachedKDSHTTPClient{
 		HTTPSGetter: trust.DefaultHTTPSGetter(),
 		logger:      log.WithGroup("cached-kds-http-client"),
-		cache:       memstore.New[string, cacheEntry](),
+		cache:       memstore.New[string, []byte](),
+		gcTicker:    gc,
 	}
+
+	go c.garbageCollect()
+	return c
 }
 
 func (c *cachedKDSHTTPClient) Get(url string) ([]byte, error) {
 	if cached, ok := c.cache.Get(url); ok {
 		c.logger.Debug("Get cached", "url", url)
-		return cached.data, nil
+		return cached, nil
 	}
 
 	c.logger.Debug("Get not cached", "url", url)
 	res, err := c.HTTPSGetter.Get(url)
 	if err != nil {
 		return nil, err
 	}
-	c.cache.Set(url, cacheEntry{
-		data: res,
-	})
+	c.cache.Set(url, res)
 	return res, nil
 }
 
-type cacheEntry struct {
-	data []byte
+func (c *cachedKDSHTTPClient) garbageCollect() {
+	for range c.gcTicker.C() {
+		c.logger.Debug("Garbage collecting")
+		c.cache.Clear()
+	}
 }

internal/memstore/memstore.go

@@ -35,3 +35,9 @@ func (s *Store[keyT, valueT]) GetAll() []valueT {
 	}
 	return values
 }
+
+func (s *Store[keyT, valueT]) Clear() {
+	s.mux.Lock()
+	defer s.mux.Unlock()
+	clear(s.m)
+}