def _build(self):
"""
This function does not yield anything only when the new state is 'streaming'
:return:
"""
timestamp = calendar.timegm(dt.now().timetuple())
lock = r.lock('fragments:{}:lock'.format(self.sink.fragment_id), lock_class=Lock)
lock.acquire()
fragment = None
try:
fragment, stream = self.fragment(stream=True, timestamp=timestamp)
if stream:
self.sink.stream = True
if fragment:
self.sink.delivery = 'mixing'
else:
self.sink.delivery = 'streaming'
else:
if fragment:
self.sink.delivery = 'pushing'
log.debug('Fragment retrieved from cache for request number {}'.format(self._request_id))
else:
self.sink.delivery = 'sent'
log.debug('Sending end stream signal since there is no fragment and stream is disabled')
yield (), {'state': 'end'}
self.sink.stream = False
except Exception as e:
log.warning(e.message)
self.sink.stream = True
self.sink.delivery = 'streaming'
finally:
lock.release()
if fragment:
log.info('Building a stream result from cache for request number {}...'.format(self._request_id))
for ch in chunks(fragment, 1000):
if ch:
yield [(map_variables(c, self.sink.mapping), s.n3(), p.n3(), o.n3()) for
(c, s, p, o)
in ch], {'source': 'store'}
lock.acquire()
try:
if self.sink.delivery == 'pushing' or (self.sink.delivery == 'mixing' and not self.sink.stream):
self.sink.delivery = 'sent'
log.info(
'The response stream of request {} is completed. Notifying...'.format(self.sink.request_id))
yield (), {'state': 'end'}
elif self.sink.delivery == 'mixing' and self.sink.stream:
self.sink.delivery = 'streaming'
finally:
lock.release()
def _build(self):
fragment, _ = self.fragment(result_set=True)
log.debug('Building a query result for request number {}'.format(self._request_id))
try:
variables = filter(lambda x: not x.startswith('_'), map(lambda v: v.lstrip('?'),
filter(lambda x: x.startswith('?'),
self.sink.preferred_labels)))
for ch in chunks(fragment, 100):
result_rows = []
for t in ch:
if any(t):
result_row = {v: t[v] for v in variables}
result_rows.append(result_row)
if result_rows:
yield json.dumps(result_rows), {'state': 'streaming', 'source': 'store',
'response_to': self.sink.message_id,
'submitted_on': calendar.timegm(datetime.now().timetuple()),
'submitted_by': self.sink.submitted_by}
except Exception, e:
log.error(e.message)
raise
