sshtargate/main.go

package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"os/signal"
	"path"
	"strings"
	"sync"
	"syscall"

	"git.sr.ht/~tslocum/sshtargate/pkg/gate"
	"github.com/anmitsu/go-shlex"
)

const (
	version = "0.0.0"

	versionInfo = `sshtargate - Host SSH portals to applications - v` + version + `
https://git.sr.ht/~tslocum/sshtargate
The MIT License (MIT)
Copyright (c) 2020 Trevor Slocum <trevor@rocketnine.space>
`
)

var (
	printVersionInfo bool
	configPath       string

	portals     []*gate.Portal
	portalsLock = new(sync.Mutex)

	done = make(chan bool)
)

func main() {
	flag.BoolVar(&printVersionInfo, "version", false, "print version information and exit")
	flag.StringVar(&configPath, "config", "", "path to configuration file")
	flag.Parse()

	if printVersionInfo {
		fmt.Print(versionInfo)
		return
	}

	// TODO: Allow portals to be specified via arguments

	// TODO: Catch SIGHUP
	sigc := make(chan os.Signal, 1)
	signal.Notify(sigc,
		syscall.SIGINT,
		syscall.SIGTERM)
	go func() {
		<-sigc

		done <- true
	}()

	log.Println("Initializing sshtargate...")

	if configPath == "" {
		homedir, err := os.UserHomeDir()
		if err == nil && homedir != "" {
			configPath = path.Join(homedir, ".config", "sshtargate", "config.yaml")
		}
	}

	err := readConfig(configPath)
	if err != nil {
		log.Fatalf("failed to read configuration file %s: %s", configPath, err)
	}

	for pname, pcfg := range config.Portals {
		cs, err := shlex.Split(pcfg.Command, true)
		if err != nil {
			log.Fatalf("failed to split command %s", pcfg.Command)
		}

		pname, pcfg := pname, pcfg // Capture
		go func() {
			wg := new(sync.WaitGroup)

			for _, address := range pcfg.Host {
				wg.Add(1)
				address := address // Capture

				go func() {
					p, err := gate.NewPortal(pname, address, cs)
					if err != nil {
						log.Fatalf("failed to start portal %s on %s: %s", pname, address, err)
					}

					portalsLock.Lock()
					portals = append(portals, p)
					portalsLock.Unlock()

					wg.Done()
				}()
			}

			wg.Wait()
			log.Printf("Opened portal %s on %s to %s", pname, strings.Join(pcfg.Host, ","), pcfg.Command)
		}()
	}

	<-done

	portalsLock.Lock()
	for _, p := range portals {
		p.Shutdown()
	}
	portalsLock.Unlock()
}