use atomic bool to be concurrent safe

Signed-off-by: Ahmad Karimi <[email protected]>

internal/contour/handler.go

@@ -28,6 +28,7 @@ import (
 
 	"github.com/projectcontour/contour/internal/dag"
 	"github.com/projectcontour/contour/internal/k8s"
+	"sync/atomic"
 )
 
 type EventHandlerConfig struct {
@@ -61,7 +62,7 @@ type EventHandler struct {
 
 	syncTracker *synctrack.SingleFileTracker
 
-	initialDagBuilt bool
+	initialDagBuilt atomic.Bool
 }
 
 func NewEventHandler(config EventHandlerConfig, upstreamHasSynced cache.InformerSynced) *EventHandler {
@@ -112,7 +113,7 @@ func (e *EventHandler) NeedLeaderElection() bool {
 }
 
 func (e *EventHandler) HasBuiltInitialDag() bool {
-	return e.initialDagBuilt
+	return e.initialDagBuilt.Load()
 }
 
 // Implements leadership.NeedLeaderElectionNotification
@@ -205,7 +206,7 @@ func (e *EventHandler) Start(ctx context.Context) error {
 			e.observer.OnChange(latestDAG)
 
 			// Allow XDS server to start (if it hasn't already).
-			e.initialDagBuilt = true
+			e.initialDagBuilt.Store(true)
 
 			// Update the status on objects.
 			for _, upd := range latestDAG.StatusCache.GetStatusUpdates() {