fix(sync): sync generator now backs off on errors (#2272)

handle unsupported features like oci artifacts.

closes: #2238

Signed-off-by: Petu Eusebiu <peusebiu@cisco.com>

pkg/extensions/sync/features/features.go

@@ -0,0 +1,53 @@
+package features
+
+import (
+	"sync"
+	"time"
+)
+
+const defaultExpireMinutes = 10
+
+type featureKey struct {
+	kind string
+	repo string
+}
+
+type featureVal struct {
+	enabled bool
+	expire  time.Time
+}
+
+type Map struct {
+	store       map[featureKey]*featureVal
+	expireAfter time.Duration
+	mu          *sync.Mutex
+}
+
+func New() *Map {
+	return &Map{
+		store:       make(map[featureKey]*featureVal),
+		expireAfter: defaultExpireMinutes * time.Minute,
+		mu:          new(sync.Mutex),
+	}
+}
+
+// returns if registry supports this feature and if ok.
+func (f *Map) Get(kind, repo string) (bool, bool) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
+	if feature, ok := f.store[featureKey{kind, repo}]; ok {
+		if time.Now().Before(feature.expire) {
+			return feature.enabled, true
+		}
+	}
+
+	// feature expired or not found
+	return false, false
+}
+
+func (f *Map) Set(kind, repo string, enabled bool) {
+	f.mu.Lock()
+	f.store[featureKey{kind: kind, repo: repo}] = &featureVal{enabled: enabled, expire: time.Now().Add(f.expireAfter)}
+	f.mu.Unlock()
+}