blob: fc7c8ee9c10d2efe39c775ae3716532ca9e3f70a [file] [log] [blame]
#!/usr/bin/env python
# Copyright 2020 The Cobalt Authors. All Rights Reserved.
#
# 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.
"""Downloads files from Google Cloud Storage given corresponding sha1s."""
import argparse
import hashlib
import logging
import os
import shutil
import stat
import tempfile
try:
import urllib.request as urllib
except ImportError:
import urllib2 as urllib
# ssl.SSLContext (and thus ssl.create_default_context) was introduced in
# python 2.7.9. depot_tools provides python 2.7.6, so we wrap this import.
try:
from ssl import create_default_context
except ImportError:
create_default_context = lambda: None
_BASE_GCS_URL = 'https://storage.googleapis.com'
_BUFFER_SIZE = 2 * 1024 * 1024
def AddExecutableBits(filename):
st = os.stat(filename)
os.chmod(filename, st.st_mode | stat.S_IRWXU | stat.S_IRWXG | stat.S_IRWXO)
def ExtractSha1(filename):
with open(filename, 'rb') as f:
sha1 = hashlib.sha1()
buf = f.read(_BUFFER_SIZE)
while buf:
sha1.update(buf)
buf = f.read(_BUFFER_SIZE)
return sha1.hexdigest()
def _DownloadFromGcsAndCheckSha1(bucket, sha1):
url = '{}/{}/{}'.format(_BASE_GCS_URL, bucket, sha1)
context = create_default_context()
res = urllib.urlopen(url, context=context) if context else urllib.urlopen(url)
if not res:
logging.error('Could not reach %s', url)
return None
with tempfile.NamedTemporaryFile(delete=False) as tmp_file:
shutil.copyfileobj(res, tmp_file)
if ExtractSha1(tmp_file.name) != sha1:
logging.error('Local and remote sha1s do not match. Skipping download.')
return None
return tmp_file
def MaybeDownloadFileFromGcs(bucket, sha1_file, output_file, force=False):
"""Download file from GCS if it doesn't already exist.
Args:
bucket: The GCS bucket that the file is stored in.
sha1_file: The file containing the sha1 of the file to download
output_file: The file to output to
force: If true, will overwrite an existing output_file
Returns:
True if it writes a file, False otherwise.
"""
if not os.path.exists(sha1_file):
logging.error("Provided sha1 file %s doesn't exist", sha1_file)
with open(sha1_file) as fd:
sha1 = fd.read().strip()
if not force and os.path.exists(output_file):
with open(output_file, 'rb') as f:
if hashlib.sha1(f.read()).hexdigest() == sha1:
logging.info('%s exists and sha1s match, skipping download',
output_file)
return False
tmp_file = _DownloadFromGcsAndCheckSha1(bucket, sha1)
if not tmp_file:
return False
shutil.move(tmp_file.name, output_file)
AddExecutableBits(output_file)
return True
def MaybeDownloadDirectoryFromGcs(bucket,
sha1_directory,
output_directory,
force=False):
res = True
for filename in os.listdir(sha1_directory):
filebase, ext = os.path.splitext(filename)
if ext == '.sha1':
filepath = os.path.join(sha1_directory, filename)
output_filepath = os.path.join(output_directory, filebase)
if not MaybeDownloadFileFromGcs(bucket, filepath, output_filepath, force):
res = False
return res
if __name__ == '__main__':
logging_format = '[%(levelname)s:%(filename)s:%(lineno)s] %(message)s'
logging.basicConfig(
level=logging.INFO, format=logging_format, datefmt='%H:%M:%S')
parser = argparse.ArgumentParser()
parser.add_argument(
'-b',
'--bucket',
required=True,
help='GCS bucket the resource is located in.')
parser.add_argument(
'-s',
'--sha1',
required=True,
help='Path to file or directory containing sha1 checksum(s).')
parser.add_argument(
'-o',
'--output',
required=True,
help='Path to file or directory to download file(s) to.')
parser.add_argument(
'-f',
'--force',
action='store_true',
help='Replace an existing resource.')
args = parser.parse_args()
if os.path.isdir(args.sha1):
MaybeDownloadDirectoryFromGcs(args.bucket, args.sha1, args.output,
args.force)
else:
MaybeDownloadFileFromGcs(args.bucket, args.sha1, args.output, args.force)