isle/go/cmd/entrypoint/main.go

package main

import (
	"context"
	"fmt"
	"isle/toolkit"
	"os"
	"os/signal"
	"path/filepath"
	"sync"
	"syscall"

	"dev.mediocregopher.com/mediocre-go-lib.git/mctx"
	"dev.mediocregopher.com/mediocre-go-lib.git/mlog"
	"github.com/adrg/xdg"
)

const systemRootPath = ""

func getSystemRootPath() string {
	if systemRootPath != "" {
		return systemRootPath
	}

	if appDirPath := os.Getenv("APPDIR"); appDirPath != "" {
		return appDirPath
	}

	return "/"
}

func getBinDirPath() string {
	return filepath.Join(getSystemRootPath(), "usr/libexec/isle")
}

func getShareDirPath() string {
	return filepath.Join(getSystemRootPath(), "usr/share/isle")
}

var (
	envCacheDir = sync.OnceValue(func() toolkit.Dir {
		cacheHome, err := toolkit.MkDir(xdg.CacheHome, true)
		if err != nil {
			panic(fmt.Errorf("creating cache directory %q: %w", xdg.CacheHome, err))
		}

		cacheDir, err := cacheHome.MkChildDir("isle", true)
		if err != nil {
			panic(fmt.Errorf("creating isle cache directory: %w", err))
		}

		return cacheDir
	})
)

func binPath(name string) string {
	return filepath.Join(getBinDirPath(), name)
}

var rootCmd = subCmd{
	name:  "isle",
	descr: "All Isle sub-commands",
	do: func(ctx subCmdCtx) error {
		return ctx.doSubCmd(
			subCmdDaemon,
			subCmdGarage,
			subCmdHost,
			subCmdNetwork,
			subCmdStorage,
			subCmdVersion,
			subCmdVPN,
		)
	},
}

func doRootCmd(
	ctx context.Context,
	logger *mlog.Logger,
	opts *subCmdCtxOpts,
) error {
	subCmdCtx := newSubCmdCtx(ctx, logger, rootCmd, opts)
	return subCmdCtx.subCmd.do(subCmdCtx)
}

func main() {
	logger := mlog.NewLogger(nil)
	defer logger.Close()

	ctx, cancel := context.WithCancel(context.Background())

	signalCh := make(chan os.Signal, 2)
	signal.Notify(signalCh, syscall.SIGINT, syscall.SIGTERM)

	go func() {
		sig := <-signalCh
		cancel()

		ctx := mctx.Annotate(ctx, "signal", sig.String())
		logger.Info(ctx, "got signal, exiting gracefully")

		sig = <-signalCh

		ctx = mctx.Annotate(ctx, "signal", sig.String())
		logger.FatalString(ctx, "second signal received, force quitting, there may be zombie children left behind, good luck!")
	}()

	if err := doRootCmd(ctx, logger, nil); err != nil {
		fmt.Fprintln(os.Stderr, err)
	}
}