gistfile1.txt

//
// main.go
// Copyright (C) 2017 unga <giulioungaretti@me.com>
//
// Distributed under terms of the MIT license.
//

package main

import (
	"io/ioutil"
	"os/exec"
	"time"

	log "github.com/Sirupsen/logrus"
)

type dB map[time.Time][]byte

func main() {
	// check every second
	ticker := time.NewTicker(time.Second * 1)
	log.Debug("Started")
	db := make(dB)
	xradnr := exec.Command("xrandr")
	grep := exec.Command("grep", "'\bconnected\b'")
	piped, err := xradnr.StdoutPipe()
	if err != nil {
		log.Fatal(err)
	}
	stderr, err := xradnr.StderrPipe()
	if err != nil {
		log.Fatal(err)
	}
	grepoutput, err := grep.StdoutPipe()
	if err != nil {
		log.Fatal(err)
	}
	greperror, err := grep.StderrPipe()
	if err != nil {
		log.Fatal(err)
	}
	grep.Stdin = piped
	for {
		select {
		case ts := <-ticker.C:
			err = xradnr.Start()
			if err != nil {
				log.Error(err)
				slurp, _ := ioutil.ReadAll(stderr)
				log.Error("wtf: %s\n", slurp)
				return
			}
			err := grep.Start()
			if err != nil {
				log.Errorf("Cant' start grep %s", err)
				return
			}
			err = grep.Wait()
			if err != nil {
				log.Error("can't wait grep %s", err)
				slurp, _ := ioutil.ReadAll(greperror)
				log.Errorf("wtf: %s\n", slurp)
				return
			}
			slurp, err := ioutil.ReadAll(grepoutput)
			if err != nil {
				log.Error("can't copy", err)
				return
			}
			db[ts] = slurp
			log.Infof("%s", slurp)
			err = xradnr.Wait()
			if err != nil {
				log.Error("can't wait xrandrx", err)
				return
			}
		}
	}
}