def __init__(self, client, path, buffer_size=DEFAULT_READ_BUFFER_SIZE):
self.client = client
self.path = path
self.bucket, self.name = parse_gcs_path(path)
self.buffer_size = buffer_size
# Get object state.
get_request = (storage.StorageObjectsGetRequest(bucket=self.bucket,
object=self.name))
try:
metadata = self._get_object_metadata(get_request)
except HttpError as http_error:
if http_error.status_code == 404:
raise IOError(errno.ENOENT, 'Not found: %s' % self.path)
else:
logging.error('HTTP error while requesting file %s: %s',
self.path, http_error)
raise
self.size = metadata.size
# Ensure read is from file of the correct generation.
get_request.generation = metadata.generation
# Initialize read buffer state.
self.download_stream = StringIO.StringIO()
self.downloader = transfer.Download(self.download_stream,
auto_transfer=False)
self.client.objects.Get(get_request, download=self.downloader)
self.position = 0
self.buffer = ''
self.buffer_start_position = 0
self.closed = False
def exists(self, path):
"""Returns whether the given gcs object exists.
Args:
path: GCS file path pattern in the form gs://<bucket>/<name>.
"""
bucket, object_path = parse_gcs_path(path)
try:
request = storage.StorageObjectsGetRequest(bucket=bucket,
object=object_path)
self.client.objects.Get(request) # metadata
return True
except IOError:
return False