feat: add bcrypt command

cmd/bcrypt.go

@@ -0,0 +1,49 @@
+package cmd
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/spf13/cobra"
+	"golang.org/x/crypto/bcrypt"
+)
+
+func init() {
+	flags := bcryptCmd.Flags()
+	flags.IntP("cost", "c", bcrypt.DefaultCost, "cost used to generate password, higher cost leads to slower verification times")
+
+	rootCmd.AddCommand(bcryptCmd)
+}
+
+var bcryptCmd = &cobra.Command{
+	Use:   "bcrypt",
+	Short: "Generate a bcrypt encrypted password",
+	Args:  cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		cost, err := cmd.Flags().GetInt("cost")
+		if err != nil {
+			return err
+		}
+
+		if cost < bcrypt.MinCost {
+			return fmt.Errorf("given cost cannot be under minimum cost of %d", bcrypt.MinCost)
+		}
+
+		if cost > bcrypt.MaxCost {
+			return fmt.Errorf("given cost cannot be over maximum cost of %d", bcrypt.MaxCost)
+		}
+
+		pwd := args[0]
+		if pwd == "" {
+			return errors.New("password argument must not be empty")
+		}
+
+		hash, err := bcrypt.GenerateFromPassword([]byte(pwd), cost)
+		if err != nil {
+			return err
+		}
+
+		fmt.Println(string(hash))
+		return nil
+	},
+}