nonceutil

type NonceService interface {
	// Before using a nonce service, it must be initialized. Failure to
	// initialize might result in panics or other unexpected results.
	Initialize() error

	// Get a nonce; returns three values:
	//
	// 1. The nonce itself, a base64-url-no-padding opaque value.
	// 2. A time at which the nonce will expire, based on the validity
	//    period specified at construction. By default, the service issues
	//    short-lived nonces.
	// 3. An error if one occurred during generation of the nonce.
	Get() (string, time.Time, error)

	// Redeem the given nonce, returning whether or not it was accepted. A
	// nonce given twice will be rejected if the service is a strict nonce
	// service, but potentially accepted if the nonce service is loose
	// (i.e., temporal revocation only).
	Redeem(string) bool

	// A hook to tidy the memory usage of the underlying implementation; is
	// implementation dependent. Some implementations may not return status
	// information.
	Tidy() *NonceStatus

	// If true, this is a strict only-once redemption service implementation,
	// else a nonce could be accepted more than once within some safety
	// window.
	IsStrict() bool

	// Whether or not this service is usable across nodes.
	IsCrossNode() bool
}

type NonceStatus struct {
	Issued      uint64
	Outstanding uint64
	Message     string
}