Golang : Send data to /dev/null a.k.a blackhole with ioutil.Discard


Tags : golang dev-nullioutil-discard blackhole logfile

In Unix/Linux system administration, there are times when the system administrator needs to reduce the size of a file to 0 immediately. Such situation usually involves log files that had taken up all the available disk space and caused other running applications that need disk space to behave oddly.

This is usually done by pointing the Unix/Linux's "black hole" (/dev/null) to the offending file. Such as:

$cat /dev/null > somefile.log

or sending an application logs to /dev/null

In Golang, the ioutil.Discard variable is similar to /dev/null and we can use it to send unwanted log output or basically any unwanted data.


 package main

 import (
  "io/ioutil"
  "log"
  "os"
 )

 func main() {

  log.Println("You can see this log message")

  // direct all log messages to /dev/null a.k.a Blackhole
  log.SetOutput(ioutil.Discard)

  log.Println("But not this log message!")

 }

References:

https://www.socketloop.com/tutorials/golang-how-to-save-log-messages-to-file

https://golang.org/pkg/io/ioutil/#pkg-variables

  See also : Golang : Secure file deletion with wipe example



Tags : golang dev-nullioutil-discard blackhole logfile

By Adam Ng(黃武俊)

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