Go language daemon start itself. Implementation

This is a creation in Article, where the information may have evolved or changed.

Package Main

Import (

"FMT"

"Log"

"Net/http"

"OS"

"Os/signal"

"Syscall"

)

Func Main () {

File, err: = OS. Create ("Log")

If err! = Nil {

Fmt. PRINTLN ("Create log file Error", err)

Return

}

Log. Setoutput (File)

CE ("pid")

}

Func CE (PID string) {

File, err: = OS. OpenFile (PID, OS. O_rdwr|os. O_create, 0644)

If err! = Nil {

Log. PRINTLN (ERR)

Return

}

Info, _: = File.stat ()

If info. Size ()! = 0 {

Log. Println ("pid file is exist")

Return

}

If OS. Getppid ()! = 1 {

Args: = Append ([]string{os. Args[0]}, OS. Args[1:] ...)

Os. StartProcess (OS. Args[0], args, &os. Procattr{files: []*os. File{os. Stdin, OS. Stdout, OS. Stderr}})

Return

}

File.writestring (FMT. Sprint (OS. Getpid ()))

c: = Make (chan os. Signal, 1)

Signal. Notify (c, OS. Interrupt, Syscall. SIGUSR2)

Go Httpserver ()

for {

S: = <-c

Switch S {

Case Syscall. SIGUSR2:

Fmt. PRINTLN ("Custom model.")

Case OS. Interrupt:

Fmt. PRINTLN ("Safe exit")

Exit (File)

}

}

}

Func Httpserver () {

http. Handlefunc ("/", route)

http. Listenandserve (": 1789", nil)

}

Func Route (W http. Responsewriter, R *http. Request) {

Log. Println (R.url. Path)

Fmt. Fprint (W, "Hello world\n")

}

Func Exit (F *os. File) {

F.close ()

Os. Remove (F.name ())

Fmt. Println ("Bye")

}