Golang : Terminate-stay-resident or daemonize your program?

Back in the old days of DOS, the concept of terminate-stay-resident via interrupt 27 is popular among programmers looking to write programs that does not terminate but remain active in the memory and can be easily invoked with couple of keys combinations. Programs such as multi-tasking utilities or viruses normally utilised terminate-stay-resident concept. In Unix/Linux world, the equivalent concept is call ...daemonizing your program.

Found this interesting package (https://github.com/icattlecoder/godaemon) from a Golang Facebook page on how to daemonize your Go program easily. All you have to do is to include the package and then add the parameter -d=true when launching your program.

For example :

 package main

 import (
 _ "github.com/icattlecoder/godaemon" //<---here!
 "log"
 "net/http"
 )

 func main() {
 mux := http.NewServeMux()
 mux.HandleFunc("/index", func(w http.ResponseWriter, r *http.Request) {
 w.Write([]byte("hello, golang!\n"))
 })
 log.Fatalln(http.ListenAndServe(":8080", mux))
 }

and

./example -d=true

~$ curl http://localhost:8080/index

hello, golang!

Now, you might ask ...won't it be easier to add '&' symbol at the end of the program to make it into a background program in Linux/Unix?

A reply in the Facebook group provides a reasonable answer :

"As far as I know, for a daemon, the process is not tied to anything except init itself. With command & the process will be killed by a SIGHUP signal when the parent dies (in this case terminal). The very first process to be started on a Unix system is init, the daemon being a child of that process means that it is not under your direct control as an non-privileged user. Running it as a daemon causes the process to fork from the init itself."

Hope this simple tutorial can be useful to you!

References :

https://www.facebook.com/groups/206770519471402/

https://github.com/icattlecoder/godaemon

http://en.wikipedia.org/wiki/Terminateandstayresidentprogram

http://en.wikipedia.org/wiki/Daemon_%28computing%29