ollie-httpgw/main.go

// ollie-httpgw - HTTP gateway for ollie session management.
//
// Supports two backend modes:
//
//	dbus (default) - translates HTTP to D-Bus calls against org.ollie.SessionManager
//	9p             - translates HTTP to 9P file operations
//
// Usage:
//
//	ollie-httpgw [start|fgstart|stop|status]        # dbus mode (default)
//	ollie-httpgw 9p [start|fgstart|stop|status]     # 9p mode
//	ollie-httpgw dbus [start|fgstart|stop|status]   # explicit dbus mode
package main

import (
	_ "embed"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"net"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"syscall"

	"9fans.net/go/plan9/client"
)

//go:embed openapi.json
var openapiSpec []byte

var (
	listen  = flag.String("listen", ":8011", "HTTP listen address")
	service = flag.String("service", "ollie", "9P service name to connect to")
	network = flag.String("net", "", "network type (unix, tcp); empty = use namespace")
	addr    = flag.String("addr", "", "9P server address; empty = use namespace service")
)

const pidFile = "ollie-httpgw.pid"

// backendMode tracks which backend we're using.
var backendMode = "dbus"

func main() {
	args := os.Args[1:]

	// Parse optional mode prefix: "dbus" or "9p"
	if len(args) > 0 {
		switch args[0] {
		case "dbus":
			backendMode = "dbus"
			args = args[1:]
		case "9p":
			backendMode = "9p"
			args = args[1:]
		}
	}

	if len(args) >= 1 {
		subcmd := args[0]
		switch subcmd {
		case "start", "fgstart", "stop", "status":
			flag.CommandLine.Parse(args[1:]) //nolint:errcheck
			ns := client.Namespace()
			if ns == "" {
				ns = os.TempDir()
			}
			pidPath := filepath.Join(ns, pidFile)
			switch subcmd {
			case "start":
				if gwRunning() {
					fmt.Println("ollie-httpgw already running")
					os.Exit(0)
				}
				daemonize(args)
			case "fgstart":
				if gwRunning() {
					fmt.Println("ollie-httpgw already running")
					os.Exit(0)
				}
				runGateway(pidPath)
			case "stop":
				stopGateway(pidPath)
			case "status":
				if gwRunning() {
					fmt.Println("ollie-httpgw running")
				} else {
					fmt.Println("ollie-httpgw not running")
					os.Exit(1)
				}
			}
			return
		}
	}

	// Legacy: no subcommand — run in foreground directly (no pid file).
	flag.CommandLine.Parse(args) //nolint:errcheck
	serve()
}

func gwRunning() bool {
	conn, err := net.Dial("tcp", *listen)
	if err == nil {
		conn.Close()
		return true
	}
	return false
}

func daemonize(subcmdArgs []string) {
	exe, _ := os.Executable()
	args := []string{backendMode, "fgstart", "-listen", *listen, "-service", *service}
	if *network != "" {
		args = append(args, "-net", *network)
	}
	if *addr != "" {
		args = append(args, "-addr", *addr)
	}
	cmd := exec.Command(exe, args...)
	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
	if err := cmd.Start(); err != nil {
		fmt.Fprintf(os.Stderr, "failed to start: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("ollie-httpgw started (pid %d, mode %s)\n", cmd.Process.Pid, backendMode)
}

func stopGateway(pidPath string) {
	data, err := os.ReadFile(pidPath)
	if err != nil {
		fmt.Println("ollie-httpgw not running")
		return
	}
	var pid int
	fmt.Sscanf(string(data), "%d", &pid)
	if pid > 0 {
		syscall.Kill(pid, syscall.SIGTERM) //nolint:errcheck
	}
	os.Remove(pidPath) //nolint:errcheck
	fmt.Println("ollie-httpgw stopped")
}

func runGateway(pidPath string) {
	os.WriteFile(pidPath, fmt.Appendf(nil, "%d", os.Getpid()), 0644) //nolint:errcheck
	serve()
	os.Remove(pidPath) //nolint:errcheck
}

func serve() {
	http.HandleFunc("/openapi.json", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		w.Write(openapiSpec)
	})

	switch backendMode {
	case "dbus":
		http.HandleFunc("/", dbusHandler)
	case "9p":
		http.HandleFunc("/", ninepHandler)
	default:
		log.Fatalf("unknown backend mode: %s", backendMode)
	}

	log.Printf("ollie-httpgw listening on %s (mode: %s)", *listen, backendMode)
	log.Fatal(http.ListenAndServe(*listen, nil))
}

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	json.NewEncoder(w).Encode(v)
}