Golang sets current limit access

With the development of network applications, dealing with the challenges of high concurrency and large traffic has become a key task faced by developers. On the premise of ensuring service quality, how to control the speed and frequency of network access has also become a very important issue. Important issues. Therefore, for network applications, flow-limited access is a very effective means of controlling traffic. This article will introduce how to use Go language to implement current limited access.

1. What is limited access?

Limited access is a means of controlling the speed and frequency of network access. In layman's terms, it means to limit the number or time of user access to prevent resource waste and excessive server pressure caused by frequent user access.

Generally, limited access should be controlled based on certain factors, such as the visitor's IP address, device type, account permissions, etc. In this way, the stability and operating efficiency of the network application system can be guaranteed without affecting normal user use.

2. Go language to implement current-limited access

The most common way to implement current-limited access using Go language is to use the Token Bucket algorithm. The main principle is: the system allocates data to each user There is a certain number of tokens, and users need to consume one token each time they visit. When the number of tokens is used up, the user can no longer access it until the token is allocated by the system again.

Below, we will implement the code to better understand how the Go language implements current-limited access.

1) Install the rate limiting library

We can use the "go.uber.org/ratelimit" library to implement rate limiting access. First, you need to use the following code to download and install:

go get go.uber.org/ratelimit

2) Use the current limiting library to limit the current flow

We can use the following code to implement the installed current limiting library:

import (

"fmt"
"time"

"go.uber.org/ratelimit"

)

func main() {

r := ratelimit.New(100) // 设置每秒钟能够访问的次数
b := r.TakeAvailable(1) // 尝试获取一个令牌
if b {
    // 成功获取
    fmt.Println("访问成功！")
} else {
    // 获取失败
    fmt.Println("访问失败！")
}

}

In the above code, we use "ratelimit.New(100 )" to set the number of accesses per second (100 times in this example), and then use "r.TakeAvailable(1)" to try to obtain a token. If the acquisition is successful, it will output "Access successful!", otherwise it will output "Access failed!".

3) Use a current limiter to limit current

We can also use other current limiting tools, such as the "golang.org/x/time/rate" package to achieve current limiting. Below, we demonstrate through code how to use the "golang.org/x/time/rate" package tool to limit current:

import (

"fmt"
"time"

"golang.org/x/time/rate"

)

func main( ) {

// 设置每秒钟能够访问的次数
r := rate.NewLimiter(100, 300)
// 循环尝试获取令牌
for i := 0; i < 200; i++ {
    // 阻塞等待，直到获取到令牌
    if r.Allow() == false {
        fmt.Println("访问失败！")
        continue
    }
    // 成功获取
    fmt.Println("访问成功！")
}

}

In the above code, we first use "rate.NewLimiter(100, 300)" to set the number of accesses per second (100 in this example), The second parameter "300" represents the capacity of the token bucket, that is, the maximum number of cached tokens. Then, we use "r.Allow()" in the loop to obtain the token. If the acquisition is successful, it will output "Access successful!", otherwise it will output "Access failed!".

3. Summary

Through the introduction of this article, we understand the basic principles of current-limited access and how the Go language implements current-limited access. In practical applications, in order to ensure the quality and stability of network services, we can carry out reasonable current limiting control based on actual conditions, while focusing on maintaining and improving network service performance.

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