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package throttled
import (
"time"
)
// GCRAStore is the interface to implement to store state for a GCRA
// rate limiter
type GCRAStore interface {
// GetWithTime returns the value of the key if it is in the store
// or -1 if it does not exist. It also returns the current time at
// the Store. The time must be representable as a positive int64
// of nanoseconds since the epoch.
//
// GCRA assumes that all instances sharing the same Store also
// share the same clock. Using separate clocks will work if the
// skew is small but not recommended in practice unless you're
// lucky enough to be hooked up to GPS or atomic clocks.
GetWithTime(key string) (int64, time.Time, error)
// SetIfNotExistsWithTTL sets the value of key only if it is not
// already set in the store it returns whether a new value was
// set. If the store supports expiring keys and a new value was
// set, the key will expire after the provided ttl.
SetIfNotExistsWithTTL(key string, value int64, ttl time.Duration) (bool, error)
// CompareAndSwapWithTTL atomically compares the value at key to
// the old value. If it matches, it sets it to the new value and
// returns true. Otherwise, it returns false. If the key does not
// exist in the store, it returns false with no error. If the
// store supports expiring keys and the swap succeeded, the key
// will expire after the provided ttl.
CompareAndSwapWithTTL(key string, old, new int64, ttl time.Duration) (bool, error)
}
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