Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type LimitStatus ¶
type LimitStatus struct {
// IsLimited is true when a given key should be rate-limited
IsLimited bool
// LimitDuration is not nil when IsLimited is true. It's the time for which a given key should be blocked before CurrentRate falls below declared in constructor requests limit
LimitDuration *time.Duration
// CurrentRate is approximated current requests rate per window size (declared in the constructor)
CurrentRate float64
}
LimitStatus represents current status of limitation for a given key
type LimitStore ¶
type LimitStore interface {
// Inc increments current window limit counter for key
Inc(key string, window time.Time) error
// Inc increments current window limit counter for key
Dec(key string, count int64, window time.Time) error
// Get gets value of previous window counter and current window counter for key
Get(key string, previousWindow, currentWindow time.Time) (prevValue, currValue int64, err error)
}
LimitStore is the interface that represents limiter internal data store. Any database struct that implements LimitStore should have functions for incrementing counter of a given key and getting counter values of a given key for previous and current window
type MapLimitStore ¶
type MapLimitStore struct {
// contains filtered or unexported fields
}
MapLimitStore represents internal limiter data database where data are stored in golang maps
func NewMapLimitStore ¶
func NewMapLimitStore(expirationTime, flushInterval time.Duration) (m *MapLimitStore)
NewMapLimitStore creates new in-memory data store for internal limiter data. Each element of MapLimitStore is set as expired after expirationTime from its last counter increment. Expired elements are removed with a period specified by the flushInterval argument
func (*MapLimitStore) Get ¶
func (m *MapLimitStore) Get(key string, previousWindow, currentWindow time.Time) (prevValue, currValue int64, err error)
Get gets value of previous window counter and current window counter for key
func (*MapLimitStore) Inc ¶
func (m *MapLimitStore) Inc(key string, window time.Time) error
Inc increments current window limit counter for key
func (*MapLimitStore) Size ¶
func (m *MapLimitStore) Size() int
Size returns current length of data map
type RateLimiter ¶
type RateLimiter struct {
// contains filtered or unexported fields
}
RateLimiter is a simple rate-limiter for any resources inspired by Cloudflare's approach: https://blog.cloudflare.com/counting-things-a-lot-of-different-things/
func New ¶
func New(dataStore LimitStore, requestsLimit int64, windowSize time.Duration) *RateLimiter
New creates new rate limiter. A dataStore is internal limiter data store, requestsLimit and windowSize are parameters of limiter e.g. requestsLimit: 5 and windowSize: 1*time.Minute means that limiter allows up to 5 requests per minute
func (*RateLimiter) Check ¶
func (r *RateLimiter) Check(key string, currentTime time.Time) (limitStatus *LimitStatus, err error)
Check checks status of rate-limiting for a key. It returns error when limiter data could not be read
Source Files