How to implement API current limiting using Go language and Redis

How to implement API current limiting using Go language and Redis

Overview:
With the rapid development of the Internet, the usage of API interfaces is also increasing. Some API interfaces may cause excessive system load or even paralysis due to too many requests. In order to ensure the stability and reliability of the system, we need to limit the current flow of the API interface. This article will introduce how to use Go language and Redis to implement API current limiting function, and provide specific code examples.

1. API current limiting principle
   API current limiting refers to restricting access to the API interface to protect the system from being overwhelmed by malicious requests or a large number of requests. Common API current limiting algorithms include counter algorithm, leaky bucket algorithm and token bucket algorithm. The token bucket algorithm is used in this article. Its principle is to control the flow of requests through token buckets.
2. Environment preparation
   Before starting, we need to ensure that the Go language and Redis are installed and the corresponding libraries are imported.
3. Implementation code
   The following is a sample code that uses Go language and Redis to implement API current limiting:

package main

import (
    "fmt"
    "github.com/go-redis/redis"
    "time"
)

const (
    MaxReqPerSec = 100 // 每秒最大请求数
)

func main() {
    client := redis.NewClient(&redis.Options{
        Addr:     "localhost:6379",
        Password: "", // 如果有密码，填入密码
        DB:       0,  // 默认数据库
    })

    // 初始化令牌桶
    client.Set("bucket", MaxReqPerSec, 0)

    // 模拟请求
    for i := 0; i < 1000; i++ {
        if allowed, err := checkAPIRequest(client); allowed {
            // 执行API请求
            fmt.Println("API request allowed")
            // ....
        } else {
            fmt.Println("API request denied")
            // ....
        }
        time.Sleep(time.Millisecond * 100)
    }
}

func checkAPIRequest(client *redis.Client) (bool, error) {
    val, err := client.Decr("bucket").Result()
    if err != nil {
        return false, err
    }

    if val < 0 {
        client.Incr("bucket")
        return false, nil
    }

    return true, nil
}

Code description:

• In In the main function, we first establish a connection with Redis, initialize a token bucket, and set the maximum number of requests per second to 100.
• checkAPIRequest function is used to check whether API requests are allowed. At each request, we take out a token from the token bucket through the client.Decr("bucket") operation. If the number of tokens is less than 0, it means that the request cannot be made and the token needs to be Add the token to the bucket and return false. If the number of tokens is greater than or equal to 0, the request is allowed and true is returned.

4. Run the code
   Save the above code as the main.go file, use the command line to enter the directory where the file is located, and execute go run main.go to run the code. The program will simulate 100 requests, with an interval of 100 milliseconds between each request. According to the maximum number of requests set, the first 100 requests should be allowed, and subsequent requests should be rejected.

Summary:
This article introduces how to use the Go language and Redis to implement the API current limiting function and control the requested traffic through the token bucket algorithm. By using this method, you can effectively protect the system from being overwhelmed by a large number of requests and improve the stability and availability of the system.

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