McSrvWrapper/serverwrapper.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os/exec"
	"path"
	"syscall"
	"time"

	"github.com/awesome-gocui/gocui"
	"github.com/pelletier/go-toml"
)

var (
	settings *toml.Tree
	srv_stdin io.WriteCloser
	srv_cmd *exec.Cmd
)


// reload settings (and maybe other things too)
func reload() {
	settings, _ = toml.LoadFile("serverwrapper.toml")
}

func settings_list(option string) []string {
	list := settings.Get(option).([]interface{})
	str_array := make([]string, len(list))
	for i := range list {
		str_array[i] = list[i].(string)
	}
	return str_array
}

//builds the cmd which is called to run the server
func build_cmd() (string, []string) {
	//for debugging
	//return "ping", []string{"8.8.8.8"}

	java_args := []string{"-jar"}

	jvm_args := settings_list("server.jvm-args")
	java_args = append(java_args, jvm_args...)

	forge_path := path.Join(settings.Get("server.directory").(string), settings.Get("server.forge").(string))
	java_args = append(java_args, forge_path)

	jar_args := settings_list("server.jar-args")
	java_args = append(java_args, jar_args...)

	return "java", java_args
}

//run the server-thread
func server_run(g *gocui.Gui) {
	//create the command
	cmd_str, cmd_args := build_cmd()
	srv_cmd = exec.Command(cmd_str, cmd_args...)

	//execute in the server directory
	srv_cmd.Dir = settings.Get("server.directory").(string)

	//connect pipes
	stdout, err := srv_cmd.StdoutPipe()
	srv_cmd.Stderr = srv_cmd.Stdout
	srv_stdin, err = srv_cmd.StdinPipe() //this one is global, because we write to it elsewhere

	//debugging stuff
	cmd_bytes := []byte(srv_cmd.String())
	ioutil.WriteFile("cmd.txt", cmd_bytes, 0644)
	
	g.Update(func(g *gocui.Gui) error {
		v, err := g.View("srv_log")
		g.SetCurrentView("srv_log")
		if err != nil {
			return err
		}
		fmt.Fprintln(v, cmd_str)
		for i := range cmd_args {
			fmt.Fprintln(v, cmd_args[i])
		}
		g.SetCurrentView("input")
		return nil
	})

	// run the process
	err = srv_cmd.Start()
	if err != nil {
		log.Panicln("Failed to call server command \"" + srv_cmd.String() + "\"")
	}

	//read pipes and write them to the ring buffer
	buf := bufio.NewScanner(stdout)
	for {
		if buf.Scan() {
			g.Update(func(g *gocui.Gui) error {
				v, err := g.View("srv_log")
				g.SetCurrentView("srv_log")
				if err != nil {
					return err
				}
				fmt.Fprintln(v, buf.Text())
				g.SetCurrentView("input")
				return nil
			})
		} else {
			time.Sleep(10 * time.Millisecond)
		}
	}
}

func main() {
	//initialize settings by "re"loading them from disk
	reload()

	//init the CUI
	g, err := gocui.NewGui(gocui.OutputNormal, true)
	if err != nil {
		log.Panicln(err)
	}
	defer g.Close()

	g.SetManagerFunc(layout)

	g.Cursor = false

	if err := g.SetKeybinding("", gocui.KeyCtrlC, gocui.ModNone, quit); err != nil {
		log.Panicln(err)
	}

	if err := g.SetKeybinding("", gocui.KeyCtrlI, gocui.ModNone, procstatus); err != nil {
		log.Panicln(err)
	}

	if err := g.SetKeybinding("", gocui.KeyCtrlD, gocui.ModNone, killserver); err != nil {
		log.Panicln(err)
	}

	go server_run(g)

	//run the CUI main loop
	if err := g.MainLoop(); err != nil && err != gocui.ErrQuit {
		log.Panicln(err)
	}
}

func inputHandler(v *gocui.View, key gocui.Key, ch rune, mod gocui.Modifier) {
	switch {
		case ch != 0 && mod == 0:
			v.EditWrite(ch)
		case key == gocui.KeyBackspace || key == gocui.KeyBackspace2:
			v.EditDelete(true)
		case key == gocui.KeyEnter:
			s := v.Buffer()
			srv_stdin.Write([]byte(s))
			v.EditDeleteToStartOfLine()
	}
}

//create or update the CUI layout
func layout(g *gocui.Gui) error {
	maxX, maxY := g.Size()

	v_log, err := g.SetView("srv_log", 0, 0, maxX-1, maxY-5, 0)
	if err != nil {
		if err != gocui.ErrUnknownView {
			return err
		}
		//*only* put initialization code for the view here
		v_log.Autoscroll = true
		v_log.Title = "Server Output"
		v_log.Overlaps = gocui.BOTTOM
	}

	v_status, err := g.SetView("status", 0, maxY-5, maxX-1, maxY-3, 0)
	if err != nil {
		if err != gocui.ErrUnknownView {
			return err
		}
		//*only* put initialization code for the view here
		v_status.Title = "Status"
		v_status.Overlaps = gocui.TOP | gocui.BOTTOM
	}

	v_in, err := g.SetView("input", 0, maxY-3, maxX-1, maxY-1, 0)
	if err != nil {
		if err != gocui.ErrUnknownView {
			return err
		}
		//*only* put initialization code for the view here
		v_in.Title = "Input"
		v_in.Editable = true
		v_in.Editor = gocui.EditorFunc(inputHandler)
		v_in.Overlaps = gocui.TOP
	}

	g.SetCurrentView("input")

	return nil
}

func killserver(g *gocui.Gui, v *gocui.View) error {

	v_status, err := g.View("status")
	if err != nil {
		return err
	}
	v_status.Clear()
	err = srv_cmd.Process.Signal(syscall.SIGTERM)
	if err != nil {
		fmt.Fprintf(v_status, fmt.Sprint(err))
	}
	err = srv_cmd.Wait()
	if err != nil {
		fmt.Fprintf(v_status, fmt.Sprint(err))
	}
	return nil
}

func procstatus(g *gocui.Gui, v *gocui.View) error {

	v_status, err := g.View("status")
	if err != nil {
		return err
	}
	v_status.Clear()
	fmt.Fprintf(v_status, fmt.Sprint(srv_cmd.ProcessState))
	return nil
}

func quit(g *gocui.Gui, v *gocui.View) error {
	v_status, err := g.View("status")
	if err != nil {
		return err
	}

	if srv_cmd != nil {
		if srv_cmd.Process != nil {			
			if srv_cmd.ProcessState != nil {
				if srv_cmd.ProcessState.Exited() {
					return gocui.ErrQuit
				} else {
					v_status.Clear()
					fmt.Fprintf(v_status, fmt.Sprint(srv_cmd.ProcessState))
				}
			} else {
				v_status.Clear()
				fmt.Fprintf(v_status, "Server process still running, sending SIGTERM... ")
				srv_cmd.Process.Signal(syscall.SIGTERM)
				err = srv_cmd.Wait()
				if err != nil {
					fmt.Fprintf(v_status, fmt.Sprint(err))
				}
				return nil
			}
		}
		
	}
	return gocui.ErrQuit
}