Merge pull request #20 from andrewslotin/18-timeout_if_db_is_locked

Timeout if DB is locked

README.md

@@ -36,3 +36,9 @@ Just provide a BoltDB filename to be opened as the first argument on the command
 ```sh
 boltbrowser <filename>
 ```
+
+To see all options that are available, run:
+
+```
+boltbrowser --help
+```

boltbrowser.go

@@ -4,6 +4,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"time"
 
 	"github.com/boltdb/bolt"
 	"github.com/nsf/termbox-go"
@@ -20,9 +21,17 @@ var memBolt *BoltDB
 
 var currentFilename string
 
+const DefaultDBOpenTimeout = time.Second
+
+var args struct {
+	DBOpenTimeout time.Duration
+}
+
 func init() {
+	flag.DurationVar(&args.DBOpenTimeout, "timeout", DefaultDBOpenTimeout, "DB file open timeout")
 	flag.Usage = func() {
-		fmt.Fprintf(os.Stdout, "Usage: %s <filename(s)>\n", ProgramName)
+		fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] <filename(s)>\nOptions:\n", ProgramName)
+		flag.PrintDefaults()
 	}
 }
 
@@ -47,8 +56,12 @@ func main() {
 	databaseFiles := flag.Args()
 	for _, databaseFile := range databaseFiles {
 		currentFilename = databaseFile
-		db, err = bolt.Open(databaseFile, 0600, nil)
-		if err != nil {
+		db, err = bolt.Open(databaseFile, 0600, &bolt.Options{Timeout: args.DBOpenTimeout})
+		if err == bolt.ErrTimeout {
+			termbox.Close()
+			fmt.Printf("File %s is locked. Make sure it's not used by another app and try again\n", databaseFile)
+			os.Exit(1)
+		} else if err != nil {
 			if len(databaseFiles) > 1 {
 				mainLoop(nil, style)
 				continue