set variables before daemon

[Martin Page]

I would like to use this library but I am not sure if it is possible to do the following.

When the code is run it will ask for a username and password.
The daemon then starts.
The child process should use the username and password provided in the parent process to check authentication of a url (on a loop).

currently using the library I just get a infinate loop of asking for a username and password (I understand why) but I dont not see how to pass variables from parent to child.

[Dakota Pollard]

@wookoouk I had to do something similar and was running into an issue with flags not being able to be read when the child process starts. I was passing in strings directly instead of prompting but I think you could follow my solution.

Things I had to do to get it working:

• check if it is currently inside a child process or not
• set variables as environment variables in order to pass it to the child

package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"time"

	"github.com/sevlyar/go-daemon"
)

func main() {
	var user string
	var pw string
	var envVars []string

	// parent process
	if !daemon.WasReborn() {

		flag.StringVar(&user, "user", "", "username")

		flag.StringVar(&pw, "pw", "", "password")
		flag.Parse()

		if user == "" {
			fmt.Println("user flag is empty")
			os.Exit(1)
		} else if pw == "" {
			fmt.Println("pw flag is empty")
			os.Exit(1)
		}

		checkAuth(user, pw)

		// get list of current env to pass to child process
		var currEnv []string
		for _, e := range os.Environ() {
			currEnv = append(currEnv, e)
		}

		// add token value for child process to read
		envVars = append(currEnv, "USER="+user)
		envVars = append(envVars, "PASS="+pw)

	} else { // child process
		user = os.Getenv("USER")
		pw = os.Getenv("PASS")
	}

	cntxt := &daemon.Context{
		PidFileName: "log",
		PidFilePerm: 0644,
		LogFileName: "pid",
		LogFilePerm: 0640,
		WorkDir:     "./",
		Umask:       027,
		Env:         envVars,
		Args:        []string{"[go-daemon sample]"},
	}

	d, err := cntxt.Reborn()
	if err != nil {
		log.Fatalln(err)
	}
	if d != nil {
		return
	}
	defer cntxt.Release()

	log.Println("- - - - - - - - - - - - - - -")
	log.Println("daemon started")

	worker(user, pw)
}

func worker(user string, pw string) {
	for {
		time.Sleep(20 * time.Minute)
		checkAuth(user, pw)
	}
}

func checkAuth(user string, pw string) {
	//do stuff
}

[Junfan Zhang]

Thanks @dpoll, it works!