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* Add an option to suppress download progress * Add a disable option to pbar to make it a no-op * Document progress
130 lines
4.3 KiB
Python
130 lines
4.3 KiB
Python
import torch
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import hashlib
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import os
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import re
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import shutil
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import sys
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import tempfile
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try:
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from requests.utils import urlparse
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import requests.get as urlopen
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requests_available = True
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except ImportError:
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requests_available = False
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if sys.version_info[0] == 2:
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from urlparse import urlparse # noqa f811
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from urllib2 import urlopen # noqa f811
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else:
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from urllib.request import urlopen
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from urllib.parse import urlparse
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try:
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from tqdm import tqdm
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except ImportError:
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tqdm = None # defined below
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# matches bfd8deac from resnet18-bfd8deac.pth
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HASH_REGEX = re.compile(r'-([a-f0-9]*)\.')
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def load_url(url, model_dir=None, map_location=None, progress=True):
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r"""Loads the Torch serialized object at the given URL.
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If the object is already present in `model_dir`, it's deserialized and
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returned. The filename part of the URL should follow the naming convention
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``filename-<sha256>.ext`` where ``<sha256>`` is the first eight or more
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digits of the SHA256 hash of the contents of the file. The hash is used to
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ensure unique names and to verify the contents of the file.
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The default value of `model_dir` is ``$TORCH_HOME/models`` where
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``$TORCH_HOME`` defaults to ``~/.torch``. The default directory can be
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overriden with the ``$TORCH_MODEL_ZOO`` environment variable.
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Args:
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url (string): URL of the object to download
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model_dir (string, optional): directory in which to save the object
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map_location (optional): a function or a dict specifying how to remap storage locations (see torch.load)
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progress (bool, optional): whether or not to display a progress bar to stderr
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Example:
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>>> state_dict = torch.utils.model_zoo.load_url('https://s3.amazonaws.com/pytorch/models/resnet18-5c106cde.pth')
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"""
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if model_dir is None:
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torch_home = os.path.expanduser(os.getenv('TORCH_HOME', '~/.torch'))
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model_dir = os.getenv('TORCH_MODEL_ZOO', os.path.join(torch_home, 'models'))
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if not os.path.exists(model_dir):
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os.makedirs(model_dir)
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parts = urlparse(url)
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filename = os.path.basename(parts.path)
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cached_file = os.path.join(model_dir, filename)
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if not os.path.exists(cached_file):
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sys.stderr.write('Downloading: "{}" to {}\n'.format(url, cached_file))
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hash_prefix = HASH_REGEX.search(filename).group(1)
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_download_url_to_file(url, cached_file, hash_prefix, progress=progress)
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return torch.load(cached_file, map_location=map_location)
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def _download_url_to_file(url, dst, hash_prefix, progress):
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u = urlopen(url)
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if requests_available:
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file_size = int(u.headers["Content-Length"])
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u = u.raw
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else:
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meta = u.info()
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if hasattr(meta, 'getheaders'):
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file_size = int(meta.getheaders("Content-Length")[0])
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else:
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file_size = int(meta.get_all("Content-Length")[0])
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f = tempfile.NamedTemporaryFile(delete=False)
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try:
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sha256 = hashlib.sha256()
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with tqdm(total=file_size, disable=not progress) as pbar:
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while True:
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buffer = u.read(8192)
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if len(buffer) == 0:
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break
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f.write(buffer)
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sha256.update(buffer)
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pbar.update(len(buffer))
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f.close()
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digest = sha256.hexdigest()
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if digest[:len(hash_prefix)] != hash_prefix:
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raise RuntimeError('invalid hash value (expected "{}", got "{}")'
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.format(hash_prefix, digest))
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shutil.move(f.name, dst)
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finally:
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f.close()
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if os.path.exists(f.name):
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os.remove(f.name)
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if tqdm is None:
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# fake tqdm if it's not installed
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class tqdm(object):
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def __init__(self, total, disable=False):
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self.total = total
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self.disable = disable
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self.n = 0
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def update(self, n):
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if self.disable:
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return
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self.n += n
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sys.stderr.write("\r{0:.1f}%".format(100 * self.n / float(self.total)))
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sys.stderr.flush()
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def __enter__(self):
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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if self.disable:
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return
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sys.stderr.write('\n')
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