mirror of
https://github.com/zebrajr/pytorch.git
synced 2025-12-07 12:21:27 +01:00
067bc141c3
Summary: a wrapper around reader with persistent file cache. Reviewed By: kennyhorror Differential Revision: D6257639 fbshipit-source-id: 113296173ca18d25b86e188e0c09e3dbd830969d
112 lines
4.0 KiB
Python
112 lines
4.0 KiB
Python
# Copyright (c) 2016-present, Facebook, Inc.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
##############################################################################
|
|
|
|
## @package cached_reader
|
|
# Module caffe2.python.cached_reader
|
|
from __future__ import absolute_import
|
|
from __future__ import division
|
|
from __future__ import print_function
|
|
from __future__ import unicode_literals
|
|
|
|
import os
|
|
|
|
from caffe2.python import core
|
|
from caffe2.python.dataio import Reader
|
|
from caffe2.python.dataset import Dataset
|
|
from caffe2.python.pipeline import pipe
|
|
from caffe2.python.task import Cluster, TaskGroup
|
|
|
|
|
|
class CachedReader(Reader):
|
|
"""
|
|
Reader with persistent in-file cache.
|
|
|
|
Example usage:
|
|
cached_reader = CachedReader(reader)
|
|
build_cache_step = cached_reader.build_cache('/tmp/cache.db')
|
|
with LocalSession() as session:
|
|
session.run(build_cache_step)
|
|
|
|
Every time new reader is created, it's expected that build_cache will be
|
|
called before setup_ex and usage of the reader. build_cache will check
|
|
existence of provided file path and in case it's missing will initialize it
|
|
by reading data from original reader. All consequent attempts to read will
|
|
ignore original reader (i.e. no additional data will be read from it).
|
|
"""
|
|
|
|
def __init__(self, reader, db_type='leveldb', name='cached_reader'):
|
|
super(CachedReader, self).__init__(reader.schema())
|
|
self.original_reader = reader
|
|
self.cache_path = None
|
|
self.ds_reader = None
|
|
self.ds = Dataset(self._schema, name)
|
|
self.db_type = db_type
|
|
self.name = name
|
|
self.field_names = self._schema.field_names()
|
|
|
|
def setup_ex(self, init_net, finish_net):
|
|
assert self.cache_path, 'build_cache must be called first'
|
|
self._init_dataset(init_net)
|
|
self._load_from_file(init_net)
|
|
self.ds_reader = self.ds.reader(init_net, batch_size=100)
|
|
|
|
def read(self, read_net):
|
|
assert self.ds_reader, 'setup must be called first'
|
|
return self.ds_reader.read(read_net)
|
|
|
|
def has_cache(self):
|
|
return self.cache_path and os.path.exists(self.cache_path)
|
|
|
|
def build_cache(self, cache_path, overwrite=False):
|
|
if not self.has_cache() or overwrite:
|
|
self.cache_path = cache_path
|
|
if self.has_cache() and not overwrite:
|
|
# cache already exists, no need to rebuild it
|
|
return core.execution_step('build_step', [])
|
|
|
|
init_net = core.Net('init')
|
|
self._init_dataset(init_net)
|
|
with Cluster(), core.NameScope(self.name), TaskGroup() as copy_tg:
|
|
pipe(self.original_reader, self.ds.writer(), num_threads=16)
|
|
copy_step = copy_tg.to_task().get_step()
|
|
save_net = core.Net('save')
|
|
self._save_to_file(save_net)
|
|
|
|
return core.execution_step('build_cache', [init_net, copy_step, save_net])
|
|
|
|
def _init_dataset(self, init_net):
|
|
with core.NameScope(self.name):
|
|
self.ds.init_empty(init_net)
|
|
|
|
def _save_to_file(self, net):
|
|
net.Save(
|
|
self.ds.content().field_blobs(),
|
|
[],
|
|
db=self.cache_path,
|
|
db_type=self.db_type,
|
|
blob_name_overrides=self.field_names,
|
|
absolute_path=True,
|
|
)
|
|
|
|
def _load_from_file(self, net):
|
|
net.Load(
|
|
[],
|
|
self.ds.content().field_blobs(),
|
|
db=self.cache_path,
|
|
db_type=self.db_type,
|
|
absolute_path=True,
|
|
source_blob_names=self.field_names,
|
|
)
|