"istio.io/istio/istioctl/pkg/clioptions"
	"istio.io/istio/pilot/pkg/model"
	"istio.io/istio/pkg/adsc"
	"istio.io/istio/pkg/kube"
)

const (
	// defaultExpirationSeconds is how long-lived a token to request (an hour)
	defaultExpirationSeconds = 60 * 60
)

// Audience to create tokens for
var tokenAudiences = []string{"istio-ca"}

// GetXdsResponse opens a gRPC connection to opts.xds and waits for a single response

// https://www.awsarchitectureblog.com/2015/03/backoff.html
func exponentialBackoffWait(r *rand.Rand, unit, cap time.Duration) func(uint) time.Duration {
	if unit > time.Hour {
		// Protect against integer overflow
		panic("unit cannot exceed one hour")
	}
	return func(attempt uint) time.Duration {
		if attempt > 16 {
			// Protect against integer overflow
			attempt = 16
		}