1、初始版本:
#想法:計時器,說白了就是延時執行指定的程序,目前自己重構python裡面的定時器不太現實,能力達不到,所以延時操作時還得用到系統定時器,不過我們可以改一下規則;把所有要進行定時操作的程序添加到特定列表中,把列表中定時時間最短程序拿出來,進行threading.Timer(time,callback)綁定,等時間超時觸發自定義的callback,執行剛剛列表取出的程序;然後把時間更新,再次把列表中時間最短的程式拿出了,繼續threading.Timer綁定,不斷的迭代循環;當有新的定時任務加入到列表時,把當前的threading.Timer綁定取消,更新清單中的時間,再次取出最短時間,進行threading.Timer綁定......
#程式碼:
import threading import time class Timer(): '''单线程下的定时器''' def __init__(self): self.queues = [] self.timer = None self.last_time = time.time() def start(self): item = self.get() if item: self.timer = threading.Timer(item[0],self.execute) self.timer.start() def add(self,item): print('add',item) self.flush_time() self.queues.append(item) self.queues.sort(key=lambda x:x[0]) if self.timer: self.timer.cancel() self.timer = None self.start() def get(self): item = None if len(self.queues) > 0: item = self.queues[0] return item def pop(self): item = None if len(self.queues) > 0: item = self.queues.pop(0) return item def flush_time(self): curr_time = time.time() for i in self.queues: i[0] = i[0] - (curr_time - self.last_time) self.last_time = curr_time def execute(self): # if self.timer: # self.timer.cancel() # self.timer = None item = self.pop() self.flush_time() if item: callback = item[1] args = item[0] callback(args) self.start()
執行與輸出:
if __name__ == '__main__': # 检测线程数 def func(): while True: print(threading.active_count()) time.sleep(1) f1 = threading.Thread(target=func) f1.start() import logging logging.basicConfig(level=logging.INFO,format="%(asctime)s %(message)s", datefmt="%m/%d/%Y %H:%M:%S [%A]") def func1(*args): logging.info('func1 %s'%args) # time.sleep(5) def func2(*args): logging.info('func2 %s' % args) # time.sleep(5) def func3(*args): logging.info('func3 %s' % args) # time.sleep(5) def func4(*args): logging.info('func4 %s' % args) # time.sleep(5) def func5(*args): logging.info('func5 %s' % args) # time.sleep(5) # 测试 t1 = Timer() logging.info('start') t1.add([5,func1]) time.sleep(0.5) t1.add([4,func2]) time.sleep(0.5) t1.add([3,func3]) time.sleep(0.5) t1.add([2,func4]) time.sleep(0.5) t1.add([1,func5]) time.sleep(5) t1.add([1,func1]) t1.add([2,func2]) t1.add([3,func3]) t1.add([4,func4]) t1.add([5,func5]) # 输出 # 2 # 07/27/2017 10:36:47 [Thursday] start # add [5, <function func1 at 0x000000D79FC77E18>] # add [4, <function func2 at 0x000000D79FCA8488>] # 3 # add [3, <function func3 at 0x000000D79FCA8510>] # add [2, <function func4 at 0x000000D79FCA8598>] # 3 # add [1, <function func5 at 0x000000D79FCA8620>] # 3 # 07/27/2017 10:36:50 [Thursday] func5 1 # 07/27/2017 10:36:51 [Thursday] func4 0.498349666595459 # 3 # 07/27/2017 10:36:51 [Thursday] func3 0.49782633781433105 # 07/27/2017 10:36:52 [Thursday] func2 0.49848270416259766 # 3 # 07/27/2017 10:36:52 [Thursday] func1 0.48449039459228516 # 2 # 2 # add [1, <function func1 at 0x000000D79FC77E18>] # add [2, <function func2 at 0x000000D79FCA8488>] # add [3, <function func3 at 0x000000D79FCA8510>] # add [4, <function func4 at 0x000000D79FCA8598>] # add [5, <function func5 at 0x000000D79FCA8620>] # 3 # 07/27/2017 10:36:55 [Thursday] func1 0.9990766048431396 # 3 # 07/27/2017 10:36:56 [Thursday] func2 0.9988017082214355 # 3 # 07/27/2017 10:36:57 [Thursday] func3 0.99928879737854 # 07/27/2017 10:36:58 [Thursday] func4 0.9991350173950195 # 3 # 3 # 07/27/2017 10:36:59 [Thursday] func5 0.9988160133361816
執行程式碼
註:查看程式碼輸出,所有的計時器都按照標定的時間依次執行,非常完美,一切看起來很美好,只是看起來,呵呵噠,當你把func裡面的time.sleep(5)啟用後,線程數蹭蹭的上來了;原因是上個定時器callback還是執行中,下個定時器已經啟動了,這時就又新增了一個線程,哎,失敗
2、修訂版本
想法:利用生成者消費者模型,用到threading.Condition條件變數;強制永遠啟用的是一個Timer!
程式碼:
##
import time import threading import logging class NewTimer(threading.Thread): '''单线程下的定时器''' def __init__(self): super().__init__() self.queues = [] self.timer = None self.cond = threading.Condition() def run(self): while True: # print('NewTimer',self.queues) self.cond.acquire() item = self.get() callback = None if not item: logging.info('NewTimer wait') self.cond.wait() elif item[0] <= time.time(): new_item = self.pop() callback = new_item[1] else: logging.info('NewTimer start sys timer and wait') self.timer = threading.Timer(item[0]-time.time(),self.execute) self.timer.start() self.cond.wait() self.cond.release() if callback: callback(item[0]) def add(self, item): # print('add', item) self.cond.acquire() item[0] = item[0] + time.time() self.queues.append(item) self.queues.sort(key=lambda x: x[0]) logging.info('NewTimer add notify') if self.timer: self.timer.cancel() self.timer = None self.cond.notify() self.cond.release() def pop(self): item = None if len(self.queues) > 0: item = self.queues.pop(0) return item def get(self): item = None if len(self.queues) > 0: item = self.queues[0] return item def execute(self): logging.info('NewTimer execute notify') self.cond.acquire() self.cond.notify() self.cond.release()
#執行與輸出:
if __name__ == '__main__': def func(): while True: print(threading.active_count()) time.sleep(1) f1 = threading.Thread(target=func) f1.start() logging.basicConfig(level=logging.INFO,format="%(asctime)s %(message)s", datefmt="%m/%d/%Y %H:%M:%S [%A]") newtimer = NewTimer() newtimer.start() def func1(*args): logging.info('func1 %s'%args) time.sleep(5) def func2(*args): logging.info('func2 %s' % args) time.sleep(5) def func3(*args): logging.info('func3 %s' % args) time.sleep(5) def func4(*args): logging.info('func4 %s' % args) time.sleep(5) def func5(*args): logging.info('func5 %s' % args) time.sleep(5) newtimer.add([5,func1]) newtimer.add([4,func2]) newtimer.add([3,func3]) newtimer.add([2,func4]) newtimer.add([1,func5]) time.sleep(1) newtimer.add([1,func1]) newtimer.add([2,func2]) newtimer.add([3,func3]) newtimer.add([4,func4]) newtimer.add([5,func5])# 输出# 2# 07/27/2017 11:26:19 [Thursday] NewTimer wait# 07/27/2017 11:26:19 [Thursday] NewTimer add notify# 07/27/2017 11:26:19 [Thursday] NewTimer add notify# 07/27/2017 11:26:19 [Thursday] NewTimer add notify# 07/27/2017 11:26:19 [Thursday] NewTimer add notify# 07/27/2017 11:26:19 [Thursday] NewTimer add notify# 07/27/2017 11:26:19 [Thursday] NewTimer start sys timer and wait# 07/27/2017 11:26:20 [Thursday] NewTimer execute notify# 4# 07/27/2017 11:26:20 [Thursday] func5 1501125980.2175007# 07/27/2017 11:26:20 [Thursday] NewTimer add notify# 07/27/2017 11:26:20 [Thursday] NewTimer add notify# 07/27/2017 11:26:20 [Thursday] NewTimer add notify# 07/27/2017 11:26:20 [Thursday] NewTimer add notify# 07/27/2017 11:26:20 [Thursday] NewTimer add notify# 3# 3# 3# 3# 3# 07/27/2017 11:26:25 [Thursday] func4 1501125981.2175007# 3# 3# 3# 3# 07/27/2017 11:26:30 [Thursday] func1 1501125981.218279# 3# 3# 3# 3# 3# 3# 07/27/2017 11:26:35 [Thursday] func3 1501125982.2175007# 3# 3# 3# 3# 07/27/2017 11:26:40 [Thursday] func2 1501125982.218279# 3# 3# 3# 3# 3# 07/27/2017 11:26:45 [Thursday] func2 1501125983.2175007# 3# 3# 3# 3# 3# 07/27/2017 11:26:50 [Thursday] func3 1501125983.218279# 3# 3# 3# 3# 3# 07/27/2017 11:26:55 [Thursday] func1 1501125984.2175007# 3# 3# 3# 3# 3# 07/27/2017 11:27:00 [Thursday] func4 1501125984.218279# 3# 3# 3# 3# 3# 07/27/2017 11:27:05 [Thursday] func5 1501125985.218279# 3# 3# 3# 3# 3# 07/27/2017 11:27:10 [Thursday] NewTimer wait
輸出
###rrreee############### ###註:這次無論如何測試線程數也不會蹭蹭的上漲,同時可以實現多定時器任務要求;缺點:用到了兩線程,沒有用到單線程去實現,第二時間精準度問題,需要等待上個定時程式執行完畢,程式才能繼續執行#######
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