i3-wrapper/main.go

package main

import (
	"flag"
	"fmt"
	"os"
	"os/exec"
	"os/signal"
	"path/filepath"
	"strings"
	"syscall"

	"git.milar.in/milarin/slices"
)

var (
	envFile = flag.String("env", "$HOME/.config/i3-wrapper/environment", "environment file with variable definitions")
)

var (
	i3      *os.Process
	running bool
)

func main() {
	logFile, err := os.Create(filepath.Join(os.Getenv("HOME"), ".i3.log"))
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
	}
	defer logFile.Close()

	os.Stdout = logFile
	os.Stderr = logFile

	fmt.Println("environment file:", os.ExpandEnv(*envFile))

	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
	go func() {
		sig := <-sigs
		running = false
		i3.Signal(sig)
	}()

	running = true
	for running {
		cmd := exec.Command("i3")
		cmd.Stdin = os.Stdin
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr

		cmd.Env = os.Environ()
		if envData, err := os.ReadFile(os.ExpandEnv(*envFile)); err == nil {
			cmd.Env = append(cmd.Env, slices.Filter(strings.Split(string(envData), "\n"), IsNotEmpty)...)
		} else {
			fmt.Println(err)
		}

		err = cmd.Start()
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
		}
		i3 = cmd.Process

		err = cmd.Wait()
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
		}

		if _, ok := err.(*exec.ExitError); ok {
			break
		}
	}
}

func IsNotEmpty(str string) bool {
	return len(strings.TrimSpace(str)) > 0
}