Add prefix scan for keys using a Trie

cmd/bitcask/scan.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+
+	"github.com/prologic/bitcask"
+)
+
+var scanCmd = &cobra.Command{
+	Use:     "scan <prefix>",
+	Aliases: []string{"search", "find"},
+	Short:   "Perform a prefis scan for keys",
+	Long: `This performa a prefix scan for keys  starting with the given
+prefix. This uses a Trie to search for matching keys and returns all matched
+keys.`,
+	Args: cobra.ExactArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		path := viper.GetString("path")
+
+		prefix := args[0]
+
+		os.Exit(scan(path, prefix))
+	},
+}
+
+func init() {
+	RootCmd.AddCommand(scanCmd)
+}
+
+func scan(path, prefix string) int {
+	db, err := bitcask.Open(path)
+	if err != nil {
+		log.WithError(err).Error("error opening database")
+		return 1
+	}
+	defer db.Close()
+
+	err = db.Scan(prefix, func(key string) error {
+		value, err := db.Get(key)
+		if err != nil {
+			log.WithError(err).Error("error reading key")
+			return err
+		}
+
+		fmt.Printf("%s\n", string(value))
+		log.WithField("key", key).WithField("value", value).Debug("key/value")
+		return nil
+	})
+	if err != nil {
+		log.WithError(err).Error("error scanning keys")
+		return 1
+	}
+
+	return 0
+}