mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-16 17:21:04 +01:00
68 lines
2.2 KiB
Go
68 lines
2.2 KiB
Go
// Copyright 2022 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package rate
|
|
|
|
import (
|
|
"sync"
|
|
"time"
|
|
)
|
|
|
|
// Sometimes will perform an action occasionally. The First, Every, and
|
|
// Interval fields govern the behavior of Do, which performs the action.
|
|
// A zero Sometimes value will perform an action exactly once.
|
|
//
|
|
// # Example: logging with rate limiting
|
|
//
|
|
// var sometimes = rate.Sometimes{First: 3, Interval: 10*time.Second}
|
|
// func Spammy() {
|
|
// sometimes.Do(func() { log.Info("here I am!") })
|
|
// }
|
|
type Sometimes struct {
|
|
First int // if non-zero, the first N calls to Do will run f.
|
|
Every int // if non-zero, every Nth call to Do will run f.
|
|
Interval time.Duration // if non-zero and Interval has elapsed since f's last run, Do will run f.
|
|
|
|
mu sync.Mutex
|
|
count int // number of Do calls
|
|
last time.Time // last time f was run
|
|
}
|
|
|
|
// Do runs the function f as allowed by First, Every, and Interval.
|
|
//
|
|
// The model is a union (not intersection) of filters. The first call to Do
|
|
// always runs f. Subsequent calls to Do run f if allowed by First or Every or
|
|
// Interval.
|
|
//
|
|
// A non-zero First:N causes the first N Do(f) calls to run f.
|
|
//
|
|
// A non-zero Every:M causes every Mth Do(f) call, starting with the first, to
|
|
// run f.
|
|
//
|
|
// A non-zero Interval causes Do(f) to run f if Interval has elapsed since
|
|
// Do last ran f.
|
|
//
|
|
// Specifying multiple filters produces the union of these execution streams.
|
|
// For example, specifying both First:N and Every:M causes the first N Do(f)
|
|
// calls and every Mth Do(f) call, starting with the first, to run f. See
|
|
// Examples for more.
|
|
//
|
|
// If Do is called multiple times simultaneously, the calls will block and run
|
|
// serially. Therefore, Do is intended for lightweight operations.
|
|
//
|
|
// Because a call to Do may block until f returns, if f causes Do to be called,
|
|
// it will deadlock.
|
|
func (s *Sometimes) Do(f func()) {
|
|
s.mu.Lock()
|
|
defer s.mu.Unlock()
|
|
if s.count == 0 ||
|
|
(s.First > 0 && s.count < s.First) ||
|
|
(s.Every > 0 && s.count%s.Every == 0) ||
|
|
(s.Interval > 0 && time.Since(s.last) >= s.Interval) {
|
|
f()
|
|
s.last = time.Now()
|
|
}
|
|
s.count++
|
|
}
|