def start_transfer(context, timeout_secs, read_file_handle, max_data_size,
write_file_handle=None, image_service=None, image_id=None,
image_meta=None):
"""Start the data transfer from the reader to the writer.
Reader writes to the pipe and the writer reads from the pipe. This means
that the total transfer time boils down to the slower of the read/write
and not the addition of the two times.
"""
if not image_meta:
image_meta = {}
# The pipe that acts as an intermediate store of data for reader to write
# to and writer to grab from.
thread_safe_pipe = io_util.ThreadSafePipe(QUEUE_BUFFER_SIZE, max_data_size)
# The read thread. In case of glance it is the instance of the
# GlanceFileRead class. The glance client read returns an iterator
# and this class wraps that iterator to provide datachunks in calls
# to read.
read_thread = io_util.IOThread(read_file_handle, thread_safe_pipe)
# In case of Glance - VMware transfer, we just need a handle to the
# HTTP Connection that is to send transfer data to the VMware datastore.
if write_file_handle:
write_thread = io_util.IOThread(thread_safe_pipe, write_file_handle)
# In case of VMware - Glance transfer, we relinquish VMware HTTP file read
# handle to Glance Client instance, but to be sure of the transfer we need
# to be sure of the status of the image on glance changing to active.
# The GlanceWriteThread handles the same for us.
elif image_service and image_id:
write_thread = io_util.GlanceWriteThread(context, thread_safe_pipe,
image_service, image_id,
image_meta)
# Start the read and write threads.
read_event = read_thread.start()
write_event = write_thread.start()
timer = timeout.Timeout(timeout_secs)
try:
# Wait on the read and write events to signal their end
read_event.wait()
write_event.wait()
except (timeout.Timeout, Exception) as exc:
# In case of any of the reads or writes raising an exception,
# stop the threads so that we un-necessarily don't keep the other one
# waiting.
read_thread.stop()
write_thread.stop()
# Log and raise the exception.
LOG.exception(exc)
raise exception.CinderException(exc)
finally:
timer.cancel()
# No matter what, try closing the read and write handles, if it so
# applies.
read_file_handle.close()
if write_file_handle:
write_file_handle.close()
def test_write(self):
queue = io_util.ThreadSafePipe(10, 30)
queue.put = mock.Mock()
write_count = 10
for _ in range(0, write_count):
queue.write([1])
exp_calls = [mock.call([1])] * write_count
self.assertEqual(exp_calls, queue.put.call_args_list)
def test_read(self):
max_size = 10
chunk_size = 10
max_transfer_size = 30
queue = io_util.ThreadSafePipe(max_size, max_transfer_size)
def get_side_effect():
return [1] * chunk_size
queue.get = mock.Mock(side_effect=get_side_effect)
while True:
data_item = queue.read(chunk_size)
if not data_item:
break
self.assertEqual(max_transfer_size, queue.transferred)
exp_calls = [mock.call()] * int(math.ceil(float(max_transfer_size) /
chunk_size))
self.assertEqual(exp_calls, queue.get.call_args_list)
def test_tell(self):
max_transfer_size = 30
queue = io_util.ThreadSafePipe(10, 30)
self.assertEqual(max_transfer_size, queue.tell())
def test_seek(self):
queue = io_util.ThreadSafePipe(10, 30)
self.assertRaises(IOError, queue.seek, 0)