Golang如何实现微服务限流策略_Golang 微服务流控实践示例

package main
<p>import (
"sync"
"time"
)</p><p>type FixedWindowLimiter struct {
maxCount   int
window     time.Duration
count      int
lastReset  time.Time
mu         sync.Mutex
}</p><p>func NewFixedWindowLimiter(maxCount int, window time.Duration) *FixedWindowLimiter {
return &FixedWindowLimiter{
maxCount:  maxCount,
window:    window,
lastReset: time.Now(),
}
}</p><p>func (l *FixedWindowLimiter) Allow() bool {
l.mu.Lock()
defer l.mu.Unlock()</p><pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">now := time.Now()
if now.Sub(l.lastReset) > l.window {
    l.count = 0
    l.lastReset = now
}

if l.count < l.maxCount {
    l.count++
    return true
}
return false

type SlidingWindowLimiter struct {
    maxCount   int
    window     time.Duration
    requests   []time.Time
    mu         sync.Mutex
}
<p>func NewSlidingWindowLimiter(maxCount int, window time.Duration) *SlidingWindowLimiter {
return &SlidingWindowLimiter{
maxCount: maxCount,
window:   window,
}
}</p><p>func (l *SlidingWindowLimiter) Allow() bool {
l.mu.Lock()
defer l.mu.Unlock()</p><pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">now := time.Now()
cutOff := now.Add(-l.window)

// 删除过期请求
i := 0
for _, t := range l.requests {
    if t.After(cutOff) {
        l.requests[i] = t
        i++
    }
}
l.requests = l.requests[:i]

if len(l.requests) < l.maxCount {
    l.requests = append(l.requests, now)
    return true
}
return false

package main
<p>import (
"fmt"
"golang.org/x/time/rate"
"time"
)</p><p>func main() {
// 每秒产生 5 个令牌，桶容量为 10
limiter := rate.NewLimiter(5, 10)</p><pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">for i := 0; i < 15; i++ {
    if limiter.Allow() {
        fmt.Printf("Request %d allowed at %v\n", i, time.Now())
    } else {
        fmt.Printf("Request %d denied\n", i)
    }
    time.Sleep(100 * time.Millisecond)
}

-- KEYS[1]: key
-- ARGV[1]: window size in seconds
-- ARGV[2]: max count
local key = KEYS[1]
local window = tonumber(ARGV[1])
local max_count = tonumber(ARGV[2])
local now = redis.call('TIME')[1]
<p>-- 清理过期数据
redis.call('ZREMRANGEBYSCORE', key, 0, now - window)</p><p>-- 获取当前请求数
local current = redis.call('ZCARD', key)</p><p>if current < max_count then
redis.call('ZADD', key, now, now)
redis.call('EXPIRE', key, window)
return 1
else
return 0
end

import (
    "context"
    "github.com/go-redis/redis/v8"
)
<p>var ctx = context.Background()</p><p>func allowByRedis(client *redis.Client, key string, windowSec, maxCount int) (bool, error) {
script := <code> local key = KEYS[1] local window = tonumber(ARGV[1]) local max_count = tonumber(ARGV[2]) local now = redis.call('TIME')[1] redis.call('ZREMRANGEBYSCORE', key, 0, now - window) local current = redis.call('ZCARD', key) if current < max_count then redis.call('ZADD', key, now, now) redis.call('EXPIRE', key, window) return 1 else return 0 end </code></p><pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">result, err := client.Eval(ctx, script, []string{key}, windowSec, maxCount).Result()
if err != nil {
    return false, err
}
return result == int64(1), nil