Golang learning web application error log collection

With the continuous development of web applications, developers are paying more and more attention to application log collection and analysis in order to quickly discover and solve problems. However, some developers may still have some confusion about error log collection for Golang web applications. This article will introduce how to use Go language-related libraries to correctly collect and record error logs of web applications.

1. Golang's log library

In Golang, the built-in log library is "log", which provides some simple functions to print log information, such as Printf, Println and Print wait. These functions can output to the console or a file, but due to the lack of some important features, such as log level, file name, line number and other information, these functions are not sufficient when developing actual web applications.

In addition to the "log" library, there are also some third-party log libraries, such as logrus, zerolog, zap, etc. These libraries provide more functionality and options to meet a variety of different needs.

2. Error logs of Web applications

Generally, the error log information of Web applications can be divided into two categories: runtime errors and request processing errors.

1. Runtime errors

Runtime errors usually refer to application crashes caused by code errors, operating environment problems, or other system errors. In this case, the error message should be logged so that the developer can find and fix the problem.

Generally speaking, runtime error log information should include the following information:

(1) Error type, such as panic, runtime error, etc.;

(2) Occurrence Error file name and line number;

(3) Error details and stack information.

2. Request processing errors

Request processing errors usually refer to errors caused by user errors, HTTP request errors, or other application errors. In this case, the request details and error information should be logged to make it easier for developers to find and fix the problem.

Generally speaking, the log information of request processing errors should include the following information:

(1) HTTP method, URL and IP address of the request;

(2) Request Error information that occurred during processing;

(3) Request processing time and response status code.

3. Use the logrus library to collect error logs

Logrus is a third-party log library, which provides a more convenient logging method and a better log output display method. This section will introduce how to use the logrus library for error log collection.

1. Logrus installation

You can install logrus through the go get command:

go get github.com/sirupsen/logrus

2. Logrus usage example

The following is a simple logrus record Example of error log:

import (
    "os"

    "github.com/sirupsen/logrus"
)

func main() {
    // 创建logrus实例
    logger := logrus.New()

    // 设置输出到文件
    file, err := os.OpenFile("errors.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    if err == nil {
        logger.Out = file
    } else {
        logger.Info("Failed to log to file, using default stderr")
    }

    // 设置日志级别为Debug
    logger.SetLevel(logrus.DebugLevel)

    // 打印运行时错误
    defer func() {
        if err := recover(); err != nil {
            logger.Error(err)
        }
    }()

    // 打印请求处理错误
    err = someFunction()
    if err != nil {
        logger.WithFields(logrus.Fields{
            "method": "GET",
            "url":    "/api/v1/users",
            "ip":     "127.0.0.1",
        }).Error(err)
    }
}

As can be seen from the above example, the process of using logrus to record error logs is very simple. You only need to create a logrus instance, set the output mode and log level, and then pass "logger.Error" Or "logger.Info" and other functions to print error logs. Through the "WeithFields" function, request information can be easily recorded.

4. Comparison of Go language log libraries

In addition to logrus, there are some other log libraries that can be used to record error logs of web applications, among which the more popular ones are zerolog ,zap etc. Each of these libraries has its own characteristics and can be selected according to specific needs.

Generally speaking, using logrus to record error logs of web applications is more convenient and efficient, and can meet the needs of most developers. However, in the actual development process, it may be necessary to make a choice based on specific circumstances.

5. Summary

Correctly collecting and analyzing error logs of web applications is very important for the stability of the application and user experience. Golang provides a variety of logging libraries, which can be selected according to actual needs. Among them, logrus is a more popular and easy-to-use one. When using logrus to record web application error logs, you need to pay attention to two aspects, including runtime errors and request processing errors.

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