def fetch(self, client, blocking, val_index, metadata):
#pylint: disable-msg=W0613
"""Handle a fetch request on this variable.
Arguments:
client - client for whom to perform fetch
blocking - is this a blocking fetch?
val_index - index of value to fetch (unused here)
"""
fetch_location = max(val_index - self._index + 1, 0)
if fetch_location > 0:
raise WorkspaceFailure(
'ifetch* only supported at beginning of FIFO')
try:
value = remove_first(self._contents)
var_metadata = remove_first(self._metadata)
value.consumed()
response = Response(var_metadata, value)
response.iterstate = (self.vid, self._index)
self._index += 1
return response
except IndexError:
if blocking:
self.add_fetcher(client)
return None
else:
raise WorkspaceFailure('no value available')
def fetch_next_task(self, worker):
"""Get the next task for a given worker, removing it from the
queues."""
try:
bcastlist = self.__broadcast_by_worker[worker]
if len(bcastlist) != 0:
return remove_first(bcastlist)
if len(self.__unicast) != 0:
return remove_first(self.__unicast)
except KeyError:
# No such worker.
pass
return None
def get_result(self, jid):
"""Get the next result for a given job id."""
if self.__results.has_key(jid):
queue = self.__results[jid]
result = remove_first(queue)
if len(queue) == 0:
del self.__results[jid]
return result
return None
def wake_one(self):
"""Wake any task waiter. This should be called any time a task is
submitted, in case there are any blocked clients ready to service the
request.
"""
if len(self.__blocked_clients) != 0:
client, request, handler = remove_first(self.__blocked_clients)
try:
val = self.workspace.task_queue_fetch(client, request)
except OperationFailure, fail:
handler(fail)
return
if val is not None:
handler(val)
else:
self.__blocked_clients.append((client, request, handler))
def wake_one(self, jid):
"""Wake one of the result waiters waiting for a given job id, if anyone
is waiting for the job.
"""
if self.__workspace.is_shutting_down:
self.kill_all()
return
if self.__blocked_clients.has_key(jid):
client = remove_first(self.__blocked_clients[jid])
try:
val = self.__workspace.result_queue_fetch(* client[0:2])
if val is None:
self.__blocked_clients[jid].append(client)
else:
client[2](val)
if len(self.__blocked_clients[jid]) == 0:
del self.__blocked_clients[jid]
except Exception:
self.__blocked_clients[jid].append(client)
raise
