Rate5/models.go

package rate5

import (
	"sync/atomic"

	"github.com/patrickmn/go-cache"
)

const (
	// DefaultWindow is the standard window of time ratelimit triggers are observed in seconds.
	DefaultWindow = 25
	// DefaultBurst is the standard amount of triggers observed within Window before ratelimiting occurs.
	DefaultBurst = 25
)

const (
	stateUnlocked uint32 = iota
	stateLocked
)

var debugChannel chan string

// Identity is an interface that allows any arbitrary type to be used for a unique key in ratelimit checks when implemented.
type Identity interface {
	UniqueKey() string
}

type rated struct {
	seen atomic.Value
	locker *uint32
}

// Limiter implements an Enforcer to create an arbitrary ratelimiter.
type Limiter struct {
	Source Identity
	// Patrons are the IRC users that we are rate limiting.
	Patrons *cache.Cache
	// Ruleset is the actual ratelimitting model.
	Ruleset Policy
	/* Debug mode (toggled here) enables debug messages
	delivered through a channel. See: DebugChannel() */
	Debug bool

	count atomic.Value
	known map[interface{}]*rated
}

// Policy defines the mechanics of our ratelimiter.
type Policy struct {
	// Window defines the duration in seconds that we should keep track of ratelimit triggers,
	Window int
	// Burst is the amount of times that Check will not trigger a limit within the duration defined by Window.
	Burst int
	// Strict mode punishes triggers of the ratelimitby increasing the amount of time they have to wait every time they trigger the limitter.
	Strict bool
}