golang glog settings

Golang is a powerful programming language that is constantly developing and improving. Golang provides a built-in standard library, which includes Glog, a library provided to developers for logging. Glog is a popular standard library in the Golang community. It is efficient, customizable and cross-platform. In this article, we will discuss how to setup Glog in Golang.

Installing Glog

First, we need to install the Glog library on the local machine. The installation steps are as follows:

1. Open a terminal and enter the following command:

   go get github.com/golang/glog

   This will download Glog from golang.org and store it in $GOPATH/src/github .com/golang/glog folder.

2. Then, go to the storage location and use the following commands to compile and install Glog:

cd $GOPATH/src/github.com/golang/glog
go install

Glog settings

Glog will store the logs by default Output to standard error output, we can use the following four levels to set the priority level of the log:

• INFO: Information level, used to output standard program running information
• WARNING: Warning level, used to output warning information
• ERROR: Error level, used to output error information
• FATAL: Fatal level, used to output fatal error information when the program is running

When we use any output level, Glog will record the logs to the specified file, and the logs can also be sent to a remote server or other places.

The following is the code to configure Glog by setting the log level and file output directory:

import (
  "flag"
  "fmt"
  "log"
  "os"
  "time"
  "github.com/golang/glog"
)

func main() {
  flag.Parse()

  // 设置要输出的日志级别
  glog.Info("这是一条输出级别为INFO的日志信息")
  glog.Warning("这是一条输出级别为WARNING的日志信息")
  glog.Error("这是一条输出级别为 ERROR的日志信息")
  glog.Fatal("这是一条输出级别为FATAL的日志信息")

  // 自定义日志文件输出目录及文件名
  logDir := "/Users/username/logs"
  logName := "app.log"
  os.MkdirAll(logDir, os.ModePerm)
  logFile := fmt.Sprintf("%s/%s-%s.log", logDir, logName, time.Now().Format("20060102"))
  logFd, err := os.OpenFile(logFile, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
  if err != nil {
    glog.Fatalf("Failed to create log file: %v", err)
  }
  defer logFd.Close()

  // 将日志输出到文件
  log.SetOutput(logFd)

  // 输出格式化后的日志信息
  log.Printf("这是一条格式化的日志信息: %s", "Custom message")
}

In the above code, we first use the flag.Parse() function to parse the command line flag. Then, we set the log level, customize the log file output directory and file name, and output the log to the specified file. It is worth noting that we use the defer keyword to ensure that the file is closed before the function exits.

Finally, we use the log.Printf() function to output the formatted information to the log file. This function is very similar to the fmt.Printf() function and implements the function of formatting and outputting log information.

Conclusion

Glog is a very good log library in Golang. It can be used to record various levels of log information, and can configure the output file and save location. This article introduces how to install, set up and use Glog to help developers more conveniently record various log information when the program is running. By using Glog to record log information, you can find and solve problems more easily, and monitor and maintain the normal operation of the program more effectively.

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