Skip to main content

restore.go

restore.go - Overview​

This file implements the restore command for the Badger database, allowing users to restore a database from a backup file.

Detailed Documentation​

var restoreFile string​

  • Purpose: Stores the path to the backup file used for restoring the database. Defaults to "badger.bak".

var maxPendingWrites int​

  • Purpose: Defines the maximum number of pending writes during the restore process. Defaults to 256.

var restoreCmd *cobra.Command​

  • Purpose: Defines the Cobra command for the restore functionality.
    • Use: "restore"
    • Short: "Restore Badger database."
    • Long: Describes the usage of the restore command, including reading a backup file and writing key-value pairs to a new database.
    • RunE: doRestore function, which executes the restore operation.

func init()​

  • Purpose: Initializes the restoreCmd by adding it to the root command and defining its flags.

  • Parameters: None

  • Returns: None

    • Defines flags:
      • backup-file: Specifies the backup file to restore from (shorthand: "f", default: "badger.bak").
      • max-pending-writes: Sets the maximum number of pending writes during restore (shorthand: "w", default: 256).

func doRestore(cmd *cobra.Command, args []string) error​

  • Purpose: Executes the database restoration process.

  • Parameters:

    • cmd: *cobra.Command - The Cobra command being executed.
    • args: []string - Command-line arguments.

  • Returns: error - An error if the restoration fails, nil otherwise.

    Steps:

    1. Checks if a database already exists at the specified directory. If so, returns an error.
    2. Opens the Badger database with default options, sets the value directory and number of versions to keep.
    3. Opens the specified backup file.
    4. Calls db.Load to restore the database from the file.
    5. Closes the database and the backup file using defer statements to ensure resources are released.

Getting Started Relevance​