def _DownloadAuthUrl(self, url, dest_dir):
"""Download a Google Storage URL using an authentication token.
If the token cannot be fetched, fallback to unauthenticated download.
Args:
url: string, the URL to download.
dest_dir: string, the path to a directory for storing metadata scripts.
Returns:
string, the path to the file storing the metadata script.
"""
dest_file = tempfile.NamedTemporaryFile(dir=dest_dir, delete=False)
dest_file.close()
dest = dest_file.name
self.logger.info(
'Downloading url from %s to %s using authentication token.', url,
dest)
if not self.token:
response = self.watcher.GetMetadata(self.token_metadata_key,
recursive=False,
retry=False)
if not response:
self.logger.info(
'Authentication token not found. Attempting unauthenticated '
'download.')
return self._DownloadUrl(url, dest_dir)
self.token = '%s %s' % (response.get(
'token_type', ''), response.get('access_token', ''))
try:
request = urlrequest.Request(url)
request.add_unredirected_header('Metadata-Flavor', 'Google')
request.add_unredirected_header('Authorization', self.token)
content = urlrequest.urlopen(request).read()
except (httpclient.HTTPException, socket.error,
urlerror.URLError) as e:
self.logger.warning('Could not download %s. %s.', url, str(e))
return None
with open(dest, 'w') as f:
f.write(content)
return dest
def _GetMetadataRequest(self, metadata_url, params=None):
"""Performs a GET request with the metadata headers.
Args:
metadata_url: string, the URL to perform a GET request on.
params: dictionary, the query parameters in the GET request.
Returns:
HTTP response from the GET request.
Raises:
urlerror.HTTPError: raises when the GET request fails.
"""
headers = {'Metadata-Flavor': 'Google'}
params = urlparse.urlencode(params or {})
url = '%s?%s' % (metadata_url, params)
request = urlrequest.Request(url, headers=headers)
return urlrequest.urlopen(request, timeout=self.timeout * 1.1)