def ask_task():
# 节点请求任务，用json作为传递任务参数的媒介
# 包含：任务id，任务资源下载地址，任务结果上传地址，任务目标节点
from TaskQueue import TaskQueue
print("node is asking for task...")
test = TaskQueue()
# 这里需要写test=，不明原因
test = test.get()
_response = jsonify(test.to_json_dict())
return _response
class Bot(threading.Thread):
'''Producer/Consumer Bot utilising TaskQueue.'''
def __init__(self, id, buffer=5):
threading.Thread.__init__(self)
self.id = id
self.daemon = True
self.buffer_time = buffer
self.q = TaskQueue()
self.last_action_time = 0
self.new_task = threading.Event()
self.task_done = threading.Event()
def schedule(self, tasks):
'''Schedule a new task by starting an independent thread.
- tasks (list): tasks to be scheduled.'''
t = threading.Thread(target=self._add_tasks,
args=(tasks, ),
daemon=True)
t.start()
def _add_tasks(self, tasks):
'''Adding tasks from a list to task queue and waiting if queue is full.'''
for task in tasks:
if self.q.full():
print('Producer: Queue full - sleeping')
self.task_done.wait()
print('Producer: Queue not full now, adding task..')
self.task_done.clear()
self.q.put(task)
print(f'Producer: Scheduled {task}')
self.new_task.set()
def run(self):
'''Runs the thread which executes tasks.
- stay idle until scheduled task time'''
while True:
if self.q.empty():
self.new_task.wait()
print('Bot: Woke up')
self.new_task.clear()
task = self._idle()
print(f'Bot executing {task}')
task.execute()
self.last_action_time = time()
self.q.task_done()
self.task_done.set()
def _idle(self):
'''Wait for next scheduled task in queue.
- If tasks are added to queue, check next task again'''
next_task = self.q.peek()
time_until = self._time_until(next_task)
print(f'Bot: Time until next task {time_until}')
flag = self.new_task.wait(timeout=time_until)
if flag:
print('Bot: New task added to queue - checking next task')
self.new_task.clear()
return self._idle()
else:
return self.q.get()
def _time_until(self, task):
'''Calculate time in seconds until scheduled task.
- Convert task.time datetime to epoch time
- Add buffer delay if scheduled task is too close to last action time'''
now = time()
time_since = now - self.last_action_time
scheduled = int(task.time.strftime('%s'))
time_until = scheduled - now
if time_until < 0:
if time_since < self.buffer_time:
time_until = time_until + self.buffer_time
else:
time_until = 0
return time_until
