[FEATURE] support BackupEngine

[raphaelauv]

would be great to be able to create a backup from python code

WDYT ?

[mahnerak]

aimrocks implements BackupEngine, however, the feature is not tested well.

Consider you have db instance of aimrocks.DB.

To backup:

backup = rocksdb.BackupEngine("test.db/backups")
backup.create_backup(db, flush_before_backup=True)

To restore:

backup = rocksdb.BackupEngine("test.db/backups")
backup.restore_latest_backup("test.db", "test.db")  # the second one is wal directory

You can browse the code for the details:

aimrocks/src/aimrocks/lib_rocksdb.pyx

Lines 2454 to 2465 in db06847

	cpdef restore_backup(self, backup_id, db_dir, wal_dir):
	cdef Status st
	cdef backup.BackupID c_backup_id
	cdef string c_db_dir
	cdef string c_wal_dir
	c_backup_id = backup_id
	c_db_dir = path_to_string(db_dir)
	c_wal_dir = path_to_string(wal_dir)
	with nogil:
	st = self.engine.RestoreDBFromBackup(

[raphaelauv]

thank for your answer

I just tried and restore_backup do not return anything

import aimrocks

rocks_db = aimrocks.DB("/tmp/example_db", aimrocks.Options())
rocks_db.put(b'1', b"toto", disable_wal=True)


backup = aimrocks.BackupEngine("test.db/backups")
backup.create_backup(rocks_db, flush_before_backup=True)

del rocks_db

backup = aimrocks.BackupEngine("test.db/backups")
rocks_db = backup.restore_latest_backup("test.db", "test.db")

print(rocks_db.get(b'1'))

give

AttributeError: 'NoneType' object has no attribute 'get'