Spaces:
Running
on
Zero
Running
on
Zero
File size: 2,635 Bytes
28c256d |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 |
# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
from pathlib import Path
from typing import Union
from .base import BaseStorageBackend
class LmdbBackend(BaseStorageBackend):
"""Lmdb storage backend.
Args:
db_path (str): Lmdb database path.
readonly (bool): Lmdb environment parameter. If True, disallow any
write operations. Defaults to True.
lock (bool): Lmdb environment parameter. If False, when concurrent
access occurs, do not lock the database. Defaults to False.
readahead (bool): Lmdb environment parameter. If False, disable the OS
filesystem readahead mechanism, which may improve random read
performance when a database is larger than RAM. Defaults to False.
**kwargs: Keyword arguments passed to `lmdb.open`.
Attributes:
db_path (str): Lmdb database path.
"""
def __init__(self,
db_path,
readonly=True,
lock=False,
readahead=False,
**kwargs):
try:
import lmdb # noqa: F401
except ImportError:
raise ImportError(
'Please run "pip install lmdb" to enable LmdbBackend.')
self.db_path = str(db_path)
self.readonly = readonly
self.lock = lock
self.readahead = readahead
self.kwargs = kwargs
self._client = None
def get(self, filepath: Union[str, Path]) -> bytes:
"""Get values according to the filepath.
Args:
filepath (str or Path): Here, filepath is the lmdb key.
Returns:
bytes: Expected bytes object.
Examples:
>>> backend = LmdbBackend('path/to/lmdb')
>>> backend.get('key')
b'hello world'
"""
if self._client is None:
self._client = self._get_client()
filepath = str(filepath)
with self._client.begin(write=False) as txn:
value_buf = txn.get(filepath.encode('ascii'))
return value_buf
def get_text(self, filepath, encoding=None):
raise NotImplementedError
def _get_client(self):
import lmdb
return lmdb.open(
self.db_path,
readonly=self.readonly,
lock=self.lock,
readahead=self.readahead,
**self.kwargs)
def __del__(self):
if self._client is not None:
self._client.close()
|