"time"

	"go.uber.org/atomic"

	"istio.io/istio/pkg/env"
	"istio.io/istio/pkg/log"
)

// Define experimental features here.
var (
	// FilterGatewayClusterConfig controls if a subset of clusters(only those required) should be pushed to gateways
	FilterGatewayClusterConfig = env.Register("PILOT_FILTER_GATEWAY_CLUSTER_CONFIG", false,

func (configgen *ConfigGeneratorImpl) BuildClusters(proxy *model.Proxy, req *model.PushRequest) ([]*discovery.Resource, model.XdsLogDetails) {
	// In Sotw, we care about all services.
	var services []*model.Service
	if features.FilterGatewayClusterConfig && proxy.Type == model.Router {
		services = req.Push.GatewayServices(proxy)
	} else {
		services = proxy.SidecarScope.Services()
	}
	return configgen.buildClusters(proxy, req, services)
}