Request retry mechanism and usage of http.Transport in Go language

http.Transport in the Go language is a very powerful network request library that provides a flexible request retry mechanism, which can help us automatically retry when a network request fails to improve the success rate of the request. This article will introduce the request retry mechanism and usage of http.Transport, and give code examples.

1. Request retry mechanism of http.Transport

http.Transport is an HTTP network request library built into the Go language. It provides a very rich set of functions and configuration items, including Includes request retry mechanism.

By default, http.Transport will automatically retry a request. The conditions for automatic retry are:

1. A network error has occurred, such as connection timeout, connection interruption, etc.;
2. The server returned a 5xx status code.

In addition, http.Transport also provides some additional retry functions, which can be configured by setting its properties. The details are as follows:

1. MaxIdleConnsPerHost: Specify each The maximum number of idle connections under a host, the default is 2;
2. MaxIdleConns: Specifies the maximum number of idle connections for the entire Transport object, the default is 100;
3. IdleConnTimeout: Specifies how long a connection lasts Automatically closes after being used, the default is 90 seconds;
4. DisableKeepAlives: used to disable the keep-alive function, if set to true, a new connection will be created for each request.

2. How to use http.Transport

Using http.Transport to retry requests is very simple. You only need to create an http.Client object and set its Transport property to An http.Transport object will do. An example is as follows:

package main

import (
    "fmt"
    "net/http"
    "time"
)

func main() {
    // 创建一个带重试机制的http.Client对象
    client := &http.Client{
        Transport: &http.Transport{
            // 设置连接超时时间为5秒
            DialTimeout: 5 * time.Second,
            // 自动重试一次请求
            MaxRetries: 1,
        },
    }

    // 发送GET请求
    resp, err := client.Get("https://www.example.com")
    if err != nil {
        fmt.Println("请求失败：", err)
        return
    }
    defer resp.Body.Close()

    // 处理响应
    // ...
}

In the above example, we created a custom http.Client object and set its Transport property to a custom http.Transport object. In the properties of the http.Transport object, we set DialTimeout to 5 seconds, which means the connection timeout is 5 seconds; we set MaxRetries to 1, which means the request is automatically retried.

3. Summary

This article introduces the request retry mechanism and usage of http.Transport in Go language. By setting the properties of the http.Transport object, we can customize the number and conditions of request retries, as well as some other related configurations. Using these functions can help us automatically retry the request when the network request fails and improve the success rate of the request.

In general, http.Transport in Go language provides a very flexible and powerful request retry function, which is very suitable for high-concurrency network request scenarios. I hope this article is helpful to you, thank you for reading!

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