415 lines
14 KiB
Python
415 lines
14 KiB
Python
|
"""Storage providers backends for Memory caching."""
|
||
|
|
|
||
|
|
import re
|
||
|
|
import os
|
||
|
|
import os.path
|
||
|
|
import datetime
|
||
|
|
import json
|
||
|
|
import shutil
|
||
|
|
import warnings
|
||
|
|
import collections
|
||
|
|
import operator
|
||
|
|
import threading
|
||
|
|
from abc import ABCMeta, abstractmethod
|
||
|
|
|
||
|
|
from .backports import concurrency_safe_rename
|
||
|
|
from .disk import mkdirp, memstr_to_bytes, rm_subdirs
|
||
|
|
from . import numpy_pickle
|
||
|
|
|
||
|
|
CacheItemInfo = collections.namedtuple('CacheItemInfo',
|
||
|
|
'path size last_access')
|
||
|
|
|
||
|
|
|
||
|
|
def concurrency_safe_write(object_to_write, filename, write_func):
|
||
|
|
"""Writes an object into a unique file in a concurrency-safe way."""
|
||
|
|
thread_id = id(threading.current_thread())
|
||
|
|
temporary_filename = '{}.thread-{}-pid-{}'.format(
|
||
|
|
filename, thread_id, os.getpid())
|
||
|
|
write_func(object_to_write, temporary_filename)
|
||
|
|
|
||
|
|
return temporary_filename
|
||
|
|
|
||
|
|
|
||
|
|
class StoreBackendBase(metaclass=ABCMeta):
|
||
|
|
"""Helper Abstract Base Class which defines all methods that
|
||
|
|
a StorageBackend must implement."""
|
||
|
|
|
||
|
|
location = None
|
||
|
|
|
||
|
|
@abstractmethod
|
||
|
|
def _open_item(self, f, mode):
|
||
|
|
"""Opens an item on the store and return a file-like object.
|
||
|
|
|
||
|
|
This method is private and only used by the StoreBackendMixin object.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
f: a file-like object
|
||
|
|
The file-like object where an item is stored and retrieved
|
||
|
|
mode: string, optional
|
||
|
|
the mode in which the file-like object is opened allowed valued are
|
||
|
|
'rb', 'wb'
|
||
|
|
|
||
|
|
Returns
|
||
|
|
-------
|
||
|
|
a file-like object
|
||
|
|
"""
|
||
|
|
|
||
|
|
@abstractmethod
|
||
|
|
def _item_exists(self, location):
|
||
|
|
"""Checks if an item location exists in the store.
|
||
|
|
|
||
|
|
This method is private and only used by the StoreBackendMixin object.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
location: string
|
||
|
|
The location of an item. On a filesystem, this corresponds to the
|
||
|
|
absolute path, including the filename, of a file.
|
||
|
|
|
||
|
|
Returns
|
||
|
|
-------
|
||
|
|
True if the item exists, False otherwise
|
||
|
|
"""
|
||
|
|
|
||
|
|
@abstractmethod
|
||
|
|
def _move_item(self, src, dst):
|
||
|
|
"""Moves an item from src to dst in the store.
|
||
|
|
|
||
|
|
This method is private and only used by the StoreBackendMixin object.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
src: string
|
||
|
|
The source location of an item
|
||
|
|
dst: string
|
||
|
|
The destination location of an item
|
||
|
|
"""
|
||
|
|
|
||
|
|
@abstractmethod
|
||
|
|
def create_location(self, location):
|
||
|
|
"""Creates a location on the store.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
location: string
|
||
|
|
The location in the store. On a filesystem, this corresponds to a
|
||
|
|
directory.
|
||
|
|
"""
|
||
|
|
|
||
|
|
@abstractmethod
|
||
|
|
def clear_location(self, location):
|
||
|
|
"""Clears a location on the store.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
location: string
|
||
|
|
The location in the store. On a filesystem, this corresponds to a
|
||
|
|
directory or a filename absolute path
|
||
|
|
"""
|
||
|
|
|
||
|
|
@abstractmethod
|
||
|
|
def get_items(self):
|
||
|
|
"""Returns the whole list of items available in the store.
|
||
|
|
|
||
|
|
Returns
|
||
|
|
-------
|
||
|
|
The list of items identified by their ids (e.g filename in a
|
||
|
|
filesystem).
|
||
|
|
"""
|
||
|
|
|
||
|
|
@abstractmethod
|
||
|
|
def configure(self, location, verbose=0, backend_options=dict()):
|
||
|
|
"""Configures the store.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
location: string
|
||
|
|
The base location used by the store. On a filesystem, this
|
||
|
|
corresponds to a directory.
|
||
|
|
verbose: int
|
||
|
|
The level of verbosity of the store
|
||
|
|
backend_options: dict
|
||
|
|
Contains a dictionary of named parameters used to configure the
|
||
|
|
store backend.
|
||
|
|
"""
|
||
|
|
|
||
|
|
|
||
|
|
class StoreBackendMixin(object):
|
||
|
|
"""Class providing all logic for managing the store in a generic way.
|
||
|
|
|
||
|
|
The StoreBackend subclass has to implement 3 methods: create_location,
|
||
|
|
clear_location and configure. The StoreBackend also has to provide
|
||
|
|
a private _open_item, _item_exists and _move_item methods. The _open_item
|
||
|
|
method has to have the same signature as the builtin open and return a
|
||
|
|
file-like object.
|
||
|
|
"""
|
||
|
|
|
||
|
|
def load_item(self, path, verbose=1, msg=None):
|
||
|
|
"""Load an item from the store given its path as a list of
|
||
|
|
strings."""
|
||
|
|
full_path = os.path.join(self.location, *path)
|
||
|
|
|
||
|
|
if verbose > 1:
|
||
|
|
if verbose < 10:
|
||
|
|
print('{0}...'.format(msg))
|
||
|
|
else:
|
||
|
|
print('{0} from {1}'.format(msg, full_path))
|
||
|
|
|
||
|
|
mmap_mode = (None if not hasattr(self, 'mmap_mode')
|
||
|
|
else self.mmap_mode)
|
||
|
|
|
||
|
|
filename = os.path.join(full_path, 'output.pkl')
|
||
|
|
if not self._item_exists(filename):
|
||
|
|
raise KeyError("Non-existing item (may have been "
|
||
|
|
"cleared).\nFile %s does not exist" % filename)
|
||
|
|
|
||
|
|
# file-like object cannot be used when mmap_mode is set
|
||
|
|
if mmap_mode is None:
|
||
|
|
with self._open_item(filename, "rb") as f:
|
||
|
|
item = numpy_pickle.load(f)
|
||
|
|
else:
|
||
|
|
item = numpy_pickle.load(filename, mmap_mode=mmap_mode)
|
||
|
|
return item
|
||
|
|
|
||
|
|
def dump_item(self, path, item, verbose=1):
|
||
|
|
"""Dump an item in the store at the path given as a list of
|
||
|
|
strings."""
|
||
|
|
try:
|
||
|
|
item_path = os.path.join(self.location, *path)
|
||
|
|
if not self._item_exists(item_path):
|
||
|
|
self.create_location(item_path)
|
||
|
|
filename = os.path.join(item_path, 'output.pkl')
|
||
|
|
if verbose > 10:
|
||
|
|
print('Persisting in %s' % item_path)
|
||
|
|
|
||
|
|
def write_func(to_write, dest_filename):
|
||
|
|
with self._open_item(dest_filename, "wb") as f:
|
||
|
|
numpy_pickle.dump(to_write, f,
|
||
|
|
compress=self.compress)
|
||
|
|
|
||
|
|
self._concurrency_safe_write(item, filename, write_func)
|
||
|
|
except: # noqa: E722
|
||
|
|
" Race condition in the creation of the directory "
|
||
|
|
|
||
|
|
def clear_item(self, path):
|
||
|
|
"""Clear the item at the path, given as a list of strings."""
|
||
|
|
item_path = os.path.join(self.location, *path)
|
||
|
|
if self._item_exists(item_path):
|
||
|
|
self.clear_location(item_path)
|
||
|
|
|
||
|
|
def contains_item(self, path):
|
||
|
|
"""Check if there is an item at the path, given as a list of
|
||
|
|
strings"""
|
||
|
|
item_path = os.path.join(self.location, *path)
|
||
|
|
filename = os.path.join(item_path, 'output.pkl')
|
||
|
|
|
||
|
|
return self._item_exists(filename)
|
||
|
|
|
||
|
|
def get_item_info(self, path):
|
||
|
|
"""Return information about item."""
|
||
|
|
return {'location': os.path.join(self.location,
|
||
|
|
*path)}
|
||
|
|
|
||
|
|
def get_metadata(self, path):
|
||
|
|
"""Return actual metadata of an item."""
|
||
|
|
try:
|
||
|
|
item_path = os.path.join(self.location, *path)
|
||
|
|
filename = os.path.join(item_path, 'metadata.json')
|
||
|
|
with self._open_item(filename, 'rb') as f:
|
||
|
|
return json.loads(f.read().decode('utf-8'))
|
||
|
|
except: # noqa: E722
|
||
|
|
return {}
|
||
|
|
|
||
|
|
def store_metadata(self, path, metadata):
|
||
|
|
"""Store metadata of a computation."""
|
||
|
|
try:
|
||
|
|
item_path = os.path.join(self.location, *path)
|
||
|
|
self.create_location(item_path)
|
||
|
|
filename = os.path.join(item_path, 'metadata.json')
|
||
|
|
|
||
|
|
def write_func(to_write, dest_filename):
|
||
|
|
with self._open_item(dest_filename, "wb") as f:
|
||
|
|
f.write(json.dumps(to_write).encode('utf-8'))
|
||
|
|
|
||
|
|
self._concurrency_safe_write(metadata, filename, write_func)
|
||
|
|
except: # noqa: E722
|
||
|
|
pass
|
||
|
|
|
||
|
|
def contains_path(self, path):
|
||
|
|
"""Check cached function is available in store."""
|
||
|
|
func_path = os.path.join(self.location, *path)
|
||
|
|
return self.object_exists(func_path)
|
||
|
|
|
||
|
|
def clear_path(self, path):
|
||
|
|
"""Clear all items with a common path in the store."""
|
||
|
|
func_path = os.path.join(self.location, *path)
|
||
|
|
if self._item_exists(func_path):
|
||
|
|
self.clear_location(func_path)
|
||
|
|
|
||
|
|
def store_cached_func_code(self, path, func_code=None):
|
||
|
|
"""Store the code of the cached function."""
|
||
|
|
func_path = os.path.join(self.location, *path)
|
||
|
|
if not self._item_exists(func_path):
|
||
|
|
self.create_location(func_path)
|
||
|
|
|
||
|
|
if func_code is not None:
|
||
|
|
filename = os.path.join(func_path, "func_code.py")
|
||
|
|
with self._open_item(filename, 'wb') as f:
|
||
|
|
f.write(func_code.encode('utf-8'))
|
||
|
|
|
||
|
|
def get_cached_func_code(self, path):
|
||
|
|
"""Store the code of the cached function."""
|
||
|
|
path += ['func_code.py', ]
|
||
|
|
filename = os.path.join(self.location, *path)
|
||
|
|
try:
|
||
|
|
with self._open_item(filename, 'rb') as f:
|
||
|
|
return f.read().decode('utf-8')
|
||
|
|
except: # noqa: E722
|
||
|
|
raise
|
||
|
|
|
||
|
|
def get_cached_func_info(self, path):
|
||
|
|
"""Return information related to the cached function if it exists."""
|
||
|
|
return {'location': os.path.join(self.location, *path)}
|
||
|
|
|
||
|
|
def clear(self):
|
||
|
|
"""Clear the whole store content."""
|
||
|
|
self.clear_location(self.location)
|
||
|
|
|
||
|
|
def reduce_store_size(self, bytes_limit):
|
||
|
|
"""Reduce store size to keep it under the given bytes limit."""
|
||
|
|
items_to_delete = self._get_items_to_delete(bytes_limit)
|
||
|
|
|
||
|
|
for item in items_to_delete:
|
||
|
|
if self.verbose > 10:
|
||
|
|
print('Deleting item {0}'.format(item))
|
||
|
|
try:
|
||
|
|
self.clear_location(item.path)
|
||
|
|
except OSError:
|
||
|
|
# Even with ignore_errors=True shutil.rmtree can raise OSError
|
||
|
|
# with:
|
||
|
|
# [Errno 116] Stale file handle if another process has deleted
|
||
|
|
# the folder already.
|
||
|
|
pass
|
||
|
|
|
||
|
|
def _get_items_to_delete(self, bytes_limit):
|
||
|
|
"""Get items to delete to keep the store under a size limit."""
|
||
|
|
if isinstance(bytes_limit, str):
|
||
|
|
bytes_limit = memstr_to_bytes(bytes_limit)
|
||
|
|
|
||
|
|
items = self.get_items()
|
||
|
|
size = sum(item.size for item in items)
|
||
|
|
|
||
|
|
to_delete_size = size - bytes_limit
|
||
|
|
if to_delete_size < 0:
|
||
|
|
return []
|
||
|
|
|
||
|
|
# We want to delete first the cache items that were accessed a
|
||
|
|
# long time ago
|
||
|
|
items.sort(key=operator.attrgetter('last_access'))
|
||
|
|
|
||
|
|
items_to_delete = []
|
||
|
|
size_so_far = 0
|
||
|
|
|
||
|
|
for item in items:
|
||
|
|
if size_so_far > to_delete_size:
|
||
|
|
break
|
||
|
|
|
||
|
|
items_to_delete.append(item)
|
||
|
|
size_so_far += item.size
|
||
|
|
|
||
|
|
return items_to_delete
|
||
|
|
|
||
|
|
def _concurrency_safe_write(self, to_write, filename, write_func):
|
||
|
|
"""Writes an object into a file in a concurrency-safe way."""
|
||
|
|
temporary_filename = concurrency_safe_write(to_write,
|
||
|
|
filename, write_func)
|
||
|
|
self._move_item(temporary_filename, filename)
|
||
|
|
|
||
|
|
def __repr__(self):
|
||
|
|
"""Printable representation of the store location."""
|
||
|
|
return '{class_name}(location="{location}")'.format(
|
||
|
|
class_name=self.__class__.__name__, location=self.location)
|
||
|
|
|
||
|
|
|
||
|
|
class FileSystemStoreBackend(StoreBackendBase, StoreBackendMixin):
|
||
|
|
"""A StoreBackend used with local or network file systems."""
|
||
|
|
|
||
|
|
_open_item = staticmethod(open)
|
||
|
|
_item_exists = staticmethod(os.path.exists)
|
||
|
|
_move_item = staticmethod(concurrency_safe_rename)
|
||
|
|
|
||
|
|
def clear_location(self, location):
|
||
|
|
"""Delete location on store."""
|
||
|
|
if (location == self.location):
|
||
|
|
rm_subdirs(location)
|
||
|
|
else:
|
||
|
|
shutil.rmtree(location, ignore_errors=True)
|
||
|
|
|
||
|
|
def create_location(self, location):
|
||
|
|
"""Create object location on store"""
|
||
|
|
mkdirp(location)
|
||
|
|
|
||
|
|
def get_items(self):
|
||
|
|
"""Returns the whole list of items available in the store."""
|
||
|
|
items = []
|
||
|
|
|
||
|
|
for dirpath, _, filenames in os.walk(self.location):
|
||
|
|
is_cache_hash_dir = re.match('[a-f0-9]{32}',
|
||
|
|
os.path.basename(dirpath))
|
||
|
|
|
||
|
|
if is_cache_hash_dir:
|
||
|
|
output_filename = os.path.join(dirpath, 'output.pkl')
|
||
|
|
try:
|
||
|
|
last_access = os.path.getatime(output_filename)
|
||
|
|
except OSError:
|
||
|
|
try:
|
||
|
|
last_access = os.path.getatime(dirpath)
|
||
|
|
except OSError:
|
||
|
|
# The directory has already been deleted
|
||
|
|
continue
|
||
|
|
|
||
|
|
last_access = datetime.datetime.fromtimestamp(last_access)
|
||
|
|
try:
|
||
|
|
full_filenames = [os.path.join(dirpath, fn)
|
||
|
|
for fn in filenames]
|
||
|
|
dirsize = sum(os.path.getsize(fn)
|
||
|
|
for fn in full_filenames)
|
||
|
|
except OSError:
|
||
|
|
# Either output_filename or one of the files in
|
||
|
|
# dirpath does not exist any more. We assume this
|
||
|
|
# directory is being cleaned by another process already
|
||
|
|
continue
|
||
|
|
|
||
|
|
items.append(CacheItemInfo(dirpath, dirsize,
|
||
|
|
last_access))
|
||
|
|
|
||
|
|
return items
|
||
|
|
|
||
|
|
def configure(self, location, verbose=1, backend_options=None):
|
||
|
|
"""Configure the store backend.
|
||
|
|
|
||
|
|
For this backend, valid store options are 'compress' and 'mmap_mode'
|
||
|
|
"""
|
||
|
|
if backend_options is None:
|
||
|
|
backend_options = {}
|
||
|
|
|
||
|
|
# setup location directory
|
||
|
|
self.location = location
|
||
|
|
if not os.path.exists(self.location):
|
||
|
|
mkdirp(self.location)
|
||
|
|
|
||
|
|
# item can be stored compressed for faster I/O
|
||
|
|
self.compress = backend_options.get('compress', False)
|
||
|
|
|
||
|
|
# FileSystemStoreBackend can be used with mmap_mode options under
|
||
|
|
# certain conditions.
|
||
|
|
mmap_mode = backend_options.get('mmap_mode')
|
||
|
|
if self.compress and mmap_mode is not None:
|
||
|
|
warnings.warn('Compressed items cannot be memmapped in a '
|
||
|
|
'filesystem store. Option will be ignored.',
|
||
|
|
stacklevel=2)
|
||
|
|
|
||
|
|
self.mmap_mode = mmap_mode
|
||
|
|
self.verbose = verbose
|