Refactor repo

cmd/litestream/main.go

@@ -0,0 +1,101 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+	"github.com/middlemost/litestream"
+)
+
+func main() {
+	m := NewMain()
+	if err := m.Run(os.Args[1:]); err == flag.ErrHelp {
+		os.Exit(1)
+	} else if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+type Main struct {
+	logger *log.Logger
+
+	SourcePath string
+	MountPath  string
+}
+
+func NewMain() *Main {
+	return &Main{
+		logger: log.New(ioutil.Discard, "", log.LstdFlags),
+	}
+}
+
+func (m *Main) Run(args []string) (err error) {
+	flagSet := flag.NewFlagSet("litestream", flag.ContinueOnError)
+	verbose := flagSet.Bool("v", false, "verbose")
+	flagSet.Usage = m.usage
+	if err := flagSet.Parse(args); err != nil {
+		return err
+	}
+
+	// Ensure src & mount paths are specified.
+	if m.SourcePath = flagSet.Arg(0); m.SourcePath == "" {
+		return errors.New("source path required")
+	} else if m.MountPath = flagSet.Arg(1); m.MountPath == "" {
+		return errors.New("mount path required")
+	}
+
+	// Setup logging, if verbose specified.
+	var config fs.Config
+	if *verbose {
+		config.Debug = debug
+		m.logger = log.New(os.Stderr, "", log.LstdFlags)
+	}
+
+	// Mount FUSE filesystem.
+	conn, err := fuse.Mount(m.MountPath, fuse.FSName("litestream"), fuse.Subtype("litestreamfs"))
+	if err != nil {
+		return err
+	}
+	defer fuse.Unmount(m.MountPath)
+	defer conn.Close()
+
+	m.logger.Printf("mounted")
+
+	s := fs.New(conn, &config)
+	return s.Serve(&litestream.FileSystem{SourcePath: m.SourcePath})
+}
+
+func (m *Main) usage() {
+	fmt.Println(`
+Litestream is a FUSE file system that automatically replicates SQLite databases.
+
+Usage:
+
+	litestream [arguments] source_dir mount_dir
+
+Arguments:
+
+	-v
+	    Enable verbose logging.
+
+`[1:])
+}
+
+// debug is a function that can be used for fs.Config.Debug.
+// It marshals the msg to JSON and prints to the log.
+func debug(msg interface{}) {
+	buf, err := json.Marshal(msg)
+	if err != nil {
+		println("debug: marshal error: %v", err)
+		return
+	}
+	log.Print("DEBUG ", string(buf))
+}