routing: avoid allocating new entry in EndpointRegistry.GetMetrics

EndpointRegistry.GetMetrics always allocates new entry even when data for the key already exists. sync.Map does not provide lazy initialization for the new value, see golang/go#44159 This change uses suggested best-effort to avoid allocating a new value on each load. Follow up on #2795 Signed-off-by: Alexander Yastrebov <[email protected]>
zalando · Jan 12, 2024 · e0ec88e · e0ec88e
1 parent 4d76a05
commit e0ec88e
Showing 1 changed file with 7 additions and 5 deletions.
diff --git a/routing/endpointregistry.go b/routing/endpointregistry.go
@@ -70,9 +70,7 @@ func newEntry() *entry {
 type EndpointRegistry struct {
 	lastSeenTimeout time.Duration
 	now             func() time.Time
-
-	// map[string]*entry
-	data sync.Map
+	data            sync.Map // map[string]*entry
 }
 
 var _ PostProcessor = &EndpointRegistry{}
@@ -129,7 +127,11 @@ func NewEndpointRegistry(o RegistryOptions) *EndpointRegistry {
 	}
 }
 
-func (r *EndpointRegistry) GetMetrics(key string) Metrics {
-	e, _ := r.data.LoadOrStore(key, newEntry())
+func (r *EndpointRegistry) GetMetrics(hostPort string) Metrics {
+	// https://github.com/golang/go/issues/44159#issuecomment-780774977
+	e, ok := r.data.Load(hostPort)
+	if !ok {
+		e, _ = r.data.LoadOrStore(hostPort, newEntry())
+	}
 	return e.(*entry)
 }