fix(race): again

Signed-off-by: Marcel Fest <marcel.fest@telekom.de>

pkg/endpoints/endpoints.go

@@ -290,8 +290,8 @@ func (p *Processor) startLeaderElection(svcCtx *servicecontext.Context, service
 		default:
 			leaseNamespace, serviceLease := lease.ServiceName(service)
 			id := lease.NewID(p.config.LeaderElectionType, leaseNamespace, serviceLease)
-			// The lease is only dropped once its last service is gone, which races
-			// with this loop noticing its own service context is done.
+			// The lease is retired once its last service is gone, so an absent one means
+			// this loop has nothing left to elect for.
 			l := p.leaseMgr.Get(id)
 			if l == nil {
 				return

pkg/services/leader.go

@@ -46,6 +46,14 @@ func (p *Processor) StartServicesLeaderElection(svcCtx *servicecontext.Context,
 		return fmt.Errorf("no existing lease found for service %q with UID %q", service.Name, service.UID)
 	}
 
+	// A cancelled service context means this call belongs to a torn-down incarnation of
+	// the service. Its replacement is built as Cancel -> Delete -> Add, so the lease
+	// fetched above may already be the replacement's. Registering on it here would let
+	// the cleanup goroutine below retire a lease that is still in use.
+	if err := svcCtx.Ctx.Err(); err != nil {
+		return fmt.Errorf("service context cancelled before election start: %w", err)
+	}
+
 	isNew := svcLease.Add(objectName)
 
 	svcLease.Lock()