How to solve the problem of request flow control and current limiting of concurrent network requests in Go language?

How to solve the problem of request flow control and current limiting of concurrent network requests in Go language?

In modern network applications, a large number of concurrent network requests are very common. For servers, if the traffic of these requests cannot be effectively controlled and restricted, it may cause the server to be overloaded or even crash. Therefore, it is very important to solve the problem of request flow control and current limiting of concurrent network requests in Go language.

A common and effective solution is to use the token bucket algorithm. This algorithm controls and limits request traffic by limiting the number of requests that can be sent per second. The specific implementation is as follows:

package main

import (
    "fmt"
    "sync"
    "time"
)

type TokenBucket struct {
    capacity  int            // 令牌桶的容量
    rate      int            // 每秒钟产生的令牌数量
    timeUnit  time.Duration  // 令牌产生的时间间隔
    available int            // 当前可用令牌数量
    mu        sync.Mutex     // 互斥锁
}

func NewTokenBucket(capacity, rate int, timeUnit time.Duration) *TokenBucket {
    return &TokenBucket{
        capacity:  capacity,
        rate:      rate,
        timeUnit:  timeUnit,
        available: capacity,
    }
}

func (tb *TokenBucket) getToken() bool {
    tb.mu.Lock()
    defer tb.mu.Unlock()
    now := time.Now()
    // 计算令牌产生的数量
    delta := int(now.Sub(tb.lastTime) / tb.timeUnit) * tb.rate
    // 更新上次令牌产生的时间
    tb.lastTime = now
    // 重新计算当前可用令牌数量
    tb.available = tb.available + delta
    if tb.available > tb.capacity {
        tb.available = tb.capacity
    }
    if tb.available < 1 {
        return false
    }
    // 使用一个令牌
    tb.available--
    return true
}

func main() {
    // 创建一个容量为100，每秒钟产生10个令牌的令牌桶
    tb := NewTokenBucket(100, 10, time.Second)

    // 模拟1000个并发请求
    var wg sync.WaitGroup
    for i := 0; i < 1000; i++ {
        wg.Add(1)
        go func() {
            defer wg.Done()
            // 判断是否可以获取令牌
            if tb.getToken() {
                // 执行网络请求
                fmt.Println("执行网络请求")
            } else {
                // 请求被拒绝
                fmt.Println("请求被限制")
            }
        }()
    }

    wg.Wait()
}

In the above example, we first define a TokenBucket structure, which includes the capacity of the token bucket, the number of tokens generated per second, and the time when tokens are generated. Interval, current number of available tokens and other information. By calling the getToken method, you can determine whether the token can currently be obtained. If so, perform a network request, otherwise the request will be restricted.

In the main function, we create a token bucket with a capacity of 100 and generate 10 tokens per second. Then 1,000 concurrent requests were simulated, and the token was obtained for network requests by calling the getToken method. As you can see, when the token is exhausted, the request is rejected.

Through the above code examples, we can clearly see how to use the token bucket algorithm to implement request flow control and flow limiting for concurrent network requests. At the same time, this method is also efficient and easy to implement, and can be easily applied to actual projects in the Go language.

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