github.com/dayvar14/tail@v0.0.0-20240222011302-f530c4fa0c9f/examples/02-closeAndReopen/main.go (about)

     1  // Tail a file, print its contents, close it and reopen it.
     2  //
     3  // In this example you can add lines to the syslog log by using the logger
     4  // command. Exit with Ctrl+C.
     5  package main
     6  
     7  import (
     8  	"fmt"
     9  	"time"
    10  
    11  	"github.com/nxadm/tail"
    12  )
    13  
    14  var logFile = "/var/log/syslog"
    15  
    16  func main() {
    17  	// Open the file
    18  	t, err := tail.TailFile(logFile, tail.Config{Follow: true})
    19  	if err != nil {
    20  		panic(err)
    21  	}
    22  
    23  	go func() {
    24  		for line := range t.Lines {
    25  			fmt.Println(line.Text)
    26  		}
    27  	}()
    28  
    29  	time.Sleep(time.Second * 5) // Give time to the go routine to print stuff
    30  	fmt.Println("Closing the logfile " + logFile)
    31  	err = t.Stop()
    32  	if err != nil {
    33  		fmt.Printf("ERROR: %s\n", err)
    34  	}
    35  	fmt.Println("Closed the logfile " + logFile)
    36  	// If you plan to reread the same file, do not call Cleanup() as inotify/Linux will get confused.
    37  	// As the documentation states: "This function is meant to be invoked from a process's exit handler".
    38  	//t.Cleanup()
    39  
    40  	// Reopen the file and print it
    41  	t, err = tail.TailFile(logFile, tail.Config{Follow: true})
    42  	if err != nil {
    43  		panic(err)
    44  	}
    45  	defer t.Cleanup()
    46  
    47  	for line := range t.Lines {
    48  		fmt.Println(line.Text)
    49  	}
    50  }