Documentation
¶
Overview ¶
Package slidingwindow provides an implementation of Sliding Window Algorithm.
Design Let's take an limiter built on slidingwindow as an example to illustrate how the slidingwindow works.
Suppose we have a limiter that permits 100 events per minute, and now the time comes at the "75s" point, then the internal sliding window will be as below:
```
Sliding Window
|-------------------------------------| | Previous Window | Current Window | window size: 60s |------------------|------------------| | 86 | 12 | |------------------|------------------| ^ ^ ^ ^ ^ | | | | | 0s 15s 60s 75s 120s
```
In this situation, the limiter has permitted 12 events during the current window, which started 15 seconds ago, and 86 events during the entire previous window. Then the count approximation during the sliding window can be calculated like this:
``` count = 86 * ((60-15)/60) + 12
= 86 * 0.75 + 12 = 76.5 events
```
In the example, count of requests is recorded in the slidingwindow. Actually we can see the request as an event, then we can record any events if we want.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
This section is empty.
Types ¶
type SlidingWindow ¶
type SlidingWindow struct {
// contains filtered or unexported fields
}
SlidingWindow sliding window consists two windows `curr` and `prev`, the window is advanced when recording events.
func NewSlidingWindow ¶
func NewSlidingWindow(size time.Duration) *SlidingWindow
NewSlidingWindow creates a new slidingwindow
func (*SlidingWindow) Count ¶
func (sw *SlidingWindow) Count() int64
func (*SlidingWindow) Record ¶
func (sw *SlidingWindow) Record()
Allow is shorthand for AllowN(time.Now(), 1).
func (*SlidingWindow) RecordN ¶
func (sw *SlidingWindow) RecordN(now time.Time, n int64)
AllowN reports whether n events may happen at time now.
func (*SlidingWindow) Size ¶
func (sw *SlidingWindow) Size() time.Duration
Size returns the time duration of one window size. Note that the size is defined to be read-only, if you need to change the size, create a new limiter with a new size instead.
Source Files