Added the same functional options to the bitcask CLI and persist options to the db store (#40)

bitcask.go

@@ -1,6 +1,7 @@
 package bitcask
 
 import (
+	"encoding/json"
 	"errors"
 	"hash/crc32"
 	"io"
@@ -245,6 +246,28 @@ func (b *Bitcask) put(key string, value []byte) (int64, int64, error) {
 	return b.curr.Write(e)
 }
 
+func (b *Bitcask) readConfig() error {
+	if internal.Exists(filepath.Join(b.path, "config.json")) {
+		data, err := ioutil.ReadFile(filepath.Join(b.path, "config.json"))
+		if err != nil {
+			return err
+		}
+
+		if err := json.Unmarshal(data, &b.config); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (b *Bitcask) writeConfig() error {
+	data, err := json.Marshal(b.config)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(filepath.Join(b.path, "config.json"), data, 0600)
+}
+
 func (b *Bitcask) reopen() error {
 	b.mu.Lock()
 	defer b.mu.Unlock()
@@ -411,9 +434,14 @@ func Open(path string, options ...Option) (*Bitcask, error) {
 		return nil, err
 	}
 
+	config, err := getConfig(path)
+	if err != nil {
+		return nil, err
+	}
+
 	bitcask := &Bitcask{
 		Flock:   flock.New(filepath.Join(path, "lock")),
-		config:  newDefaultConfig(),
+		config:  config,
 		options: options,
 		path:    path,
 	}
@@ -435,6 +463,10 @@ func Open(path string, options ...Option) (*Bitcask, error) {
 		return nil, ErrDatabaseLocked
 	}
 
+	if err := bitcask.writeConfig(); err != nil {
+		return nil, err
+	}
+
 	if err := bitcask.reopen(); err != nil {
 		return nil, err
 	}

cmd/bitcask/initdb.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"os"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+
+	"github.com/prologic/bitcask"
+)
+
+var initdbCmd = &cobra.Command{
+	Use:     "initdb",
+	Aliases: []string{"create", "init"},
+	Short:   "Initialize a new database",
+	Long:    `This initializes a new database with persisted options`,
+	Args:    cobra.ExactArgs(0),
+	PreRun: func(cmd *cobra.Command, args []string) {
+		viper.BindPFlag("with-max-datafile-size", cmd.Flags().Lookup("with-max-datafile-size"))
+		viper.SetDefault("with-max-datafile-size", bitcask.DefaultMaxDatafileSize)
+
+		viper.BindPFlag("with-max-key-size", cmd.Flags().Lookup("with-max-key-size"))
+		viper.SetDefault("with-max-key-size", bitcask.DefaultMaxKeySize)
+
+		viper.BindPFlag("with-max-value-size", cmd.Flags().Lookup("with-max-value-size"))
+		viper.SetDefault("with-max-value-size", bitcask.DefaultMaxValueSize)
+	},
+	Run: func(cmd *cobra.Command, args []string) {
+		path := viper.GetString("path")
+
+		maxDatafileSize := viper.GetInt("with-max-datafile-size")
+		maxKeySize := viper.GetInt("with-max-key-size")
+		maxValueSize := viper.GetInt("with-max-value-size")
+
+		db, err := bitcask.Open(
+			path,
+			bitcask.WithMaxDatafileSize(maxDatafileSize),
+			bitcask.WithMaxKeySize(maxKeySize),
+			bitcask.WithMaxValueSize(maxValueSize),
+		)
+		if err != nil {
+			log.WithError(err).Error("error opening database")
+			os.Exit(1)
+		}
+		defer db.Close()
+
+		os.Exit(0)
+	},
+}
+
+func init() {
+	RootCmd.AddCommand(initdbCmd)
+
+	initdbCmd.PersistentFlags().IntP(
+		"with-max-datafile-size", "", bitcask.DefaultMaxDatafileSize,
+		"Maximum size of each datafile",
+	)
+	initdbCmd.PersistentFlags().IntP(
+		"with-max-key-size", "", bitcask.DefaultMaxKeySize,
+		"Maximum size of each key",
+	)
+	initdbCmd.PersistentFlags().IntP(
+		"with-max-value-size", "", bitcask.DefaultMaxValueSize,
+		"Maximum size of each value",
+	)
+}

options.go

@@ -1,6 +1,11 @@
 package bitcask
 
-import "errors"
+import (
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"path/filepath"
+)
 
 const (
 	// DefaultMaxDatafileSize is the default maximum datafile size in bytes
@@ -29,6 +34,43 @@ type config struct {
 	maxConcurrency  *int
 }
 
+func (c *config) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		MaxDatafileSize int `json:"max_datafile_size"`
+		MaxKeySize      int `json:"max_key_size"`
+		MaxValueSize    int `json:"max_value_size"`
+	}{
+		MaxDatafileSize: c.maxDatafileSize,
+		MaxKeySize:      c.maxKeySize,
+		MaxValueSize:    c.maxValueSize,
+	})
+}
+
+func getConfig(path string) (*config, error) {
+	type Config struct {
+		MaxDatafileSize int `json:"max_datafile_size"`
+		MaxKeySize      int `json:"max_key_size"`
+		MaxValueSize    int `json:"max_value_size"`
+	}
+
+	var cfg Config
+
+	data, err := ioutil.ReadFile(filepath.Join(path, "config.json"))
+	if err != nil {
+		return nil, err
+	}
+
+	if err := json.Unmarshal(data, &cfg); err != nil {
+		return nil, err
+	}
+
+	return &config{
+		maxDatafileSize: cfg.MaxDatafileSize,
+		maxKeySize:      cfg.MaxKeySize,
+		maxValueSize:    cfg.MaxValueSize,
+	}, nil
+}
+
 func newDefaultConfig() *config {
 	return &config{
 		maxDatafileSize: DefaultMaxDatafileSize,