Add basic structure for boltDB local storage

See #9

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Send report with the scheduler actions periodically
 - Output to a log file using logrus library
 - Log verbosity defined in configuration
+- BoltDB storage for tracking backups locally
 
 ### Fixed
 - Add sample configuration file to deb and txz packages

internal/storage/boltdb.go

@@ -0,0 +1,120 @@
+package storage
+
+import (
+	"encoding/json"
+
+	"github.com/boltdb/bolt"
+	"github.com/pkg/errors"
+	"github.com/rafaeljusto/toglacier/internal/cloud"
+	"github.com/rafaeljusto/toglacier/internal/log"
+)
+
+var boltDBBucket = []byte("toglacier")
+
+const boltDBFileMode = 0600
+
+type BoltDB struct {
+	logger   log.Logger
+	Filename string
+}
+
+func NewBoltDB(filename string, logger log.Logger) *BoltDB {
+	return &BoltDB{
+		logger:   logger,
+		Filename: filename,
+	}
+}
+
+func (b *BoltDB) Save(backup cloud.Backup) error {
+	db, err := bolt.Open(b.Filename, boltDBFileMode, nil)
+	if err != nil {
+		return errors.WithStack(newError(ErrorCodeOpeningFile, err))
+	}
+	defer db.Close()
+
+	encoded, err := json.Marshal(b)
+	if err != nil {
+		return errors.WithStack(newError(ErrorCodeEncodingBackup, err))
+	}
+
+	err = db.Update(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(boltDBBucket)
+		if bucket == nil {
+			return errors.WithStack(newError(ErrorCodeDatabaseNotFound, nil))
+		}
+
+		if err := bucket.Put([]byte(backup.ID), encoded); err != nil {
+			return errors.WithStack(newError(ErrorCodeSave, err))
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		return errors.WithStack(newError(ErrorCodeWritingFile, err))
+	}
+
+	return nil
+}
+
+func (b BoltDB) List() ([]cloud.Backup, error) {
+	db, err := bolt.Open(b.Filename, boltDBFileMode, nil)
+	if err != nil {
+		return nil, errors.WithStack(newError(ErrorCodeOpeningFile, err))
+	}
+	defer db.Close()
+
+	var backups []cloud.Backup
+
+	db.View(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(boltDBBucket)
+		if bucket == nil {
+			// no backup stored yet
+			return nil
+		}
+
+		err := bucket.ForEach(func(k, v []byte) error {
+			var backup cloud.Backup
+			if err := json.Unmarshal(v, &backup); err != nil {
+				return errors.WithStack(newError(ErrorCodeDecodingBackup, err))
+			}
+			backups = append(backups, backup)
+			return nil
+		})
+
+		if err != nil {
+			return errors.WithStack(newError(ErrorCodeListing, err))
+		}
+
+		return nil
+	})
+
+	return backups, nil
+}
+
+func (b BoltDB) Remove(id string) error {
+	db, err := bolt.Open(b.Filename, boltDBFileMode, nil)
+	if err != nil {
+		return errors.WithStack(newError(ErrorCodeOpeningFile, err))
+	}
+	defer db.Close()
+
+	err = db.Update(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(boltDBBucket)
+		if bucket == nil {
+			return errors.WithStack(newError(ErrorCodeDatabaseNotFound, nil))
+		}
+
+		if err := bucket.Delete([]byte(id)); err != nil {
+			return errors.WithStack(newError(ErrorCodeDelete, err))
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		return errors.WithStack(newError(ErrorCodeWritingFile, err))
+	}
+
+	return nil
+}

internal/storage/error.go

@@ -29,6 +29,25 @@ const (
 
 	// ErrorCodeDateFormat strange date format found in the local storage file.
 	ErrorCodeDateFormat ErrorCode = "date-format"
+
+	// ErrorCodeEncodingBackup failed to encode the backup to a storage
+	// representation.
+	ErrorCodeEncodingBackup ErrorCode = "encoding-backup"
+
+	// ErrorCodeDecodingBackup failed to decode the backup to the original format.
+	ErrorCodeDecodingBackup ErrorCode = "decoding-backup"
+
+	// ErrorCodeDatabaseNotFound database wasn't found.
+	ErrorCodeDatabaseNotFound ErrorCode = "database-not-found"
+
+	// ErrorCodeListing failed to list the backups from the database.
+	ErrorCodeListing ErrorCode = "listing"
+
+	// ErrorCodeSave failed to save the item in the database.
+	ErrorCodeSave ErrorCode = "save"
+
+	// ErrorCodeDelete failed to remove the item from the database.
+	ErrorCodeDelete ErrorCode = "delete"
 )
 
 // ErrorCode stores the error type that occurred while managing the local
@@ -50,6 +69,18 @@ func (e ErrorCode) String() string {
 		return "unexpected storage file format"
 	case ErrorCodeDateFormat:
 		return "invalid date format"
+	case ErrorCodeEncodingBackup:
+		return "failed to encode backup to a storage representation"
+	case ErrorCodeDecodingBackup:
+		return "failed to decode backup to the original representation"
+	case ErrorCodeDatabaseNotFound:
+		return "database not found"
+	case ErrorCodeListing:
+		return "failed to list backups in the database"
+	case ErrorCodeSave:
+		return "failed to save the item in the database"
+	case ErrorCodeDelete:
+		return "failed to remove the item from the database"
 	}
 
 	return "unknown error code"