在装饰器内使用多处理会产生错误:无法解决功能...它找不到

Question

我遇到了一个我无法解决的问题,它与多处理相关并在装饰器中使用它.

当我run_in_parallels使用多处理调用方法时,我收到错误:

Can't pickle <function run_testcase at 0x00000000027789C8>: it's not found as __main__.run_testcase

调用发生在装饰器内部,然后是上述问题.在run_in_parallels没有装饰器的情况下调用相同的方法时,所有工作正常.

这个问题的原因是什么？

---

file: w_PythonHelper.py

desc:函数'run_in_parallel'用于同时运行多个进程.第一种方法,即结束操作将停止其他操作.

from multiprocessing import Process,Event

class ExtProcess(Process):
    def __init__(self, event,*args,**kwargs):
        self.event=event
        Process.__init__(self,*args,**kwargs)

    def run(self):
        Process.run(self)
        self.event.set()

class PythonHelper(object):
    @staticmethod
    def run_in_parallel(*functions):
        event=Event()
        processes=dict()
        for function in functions:
            fname=function[0]
            try:fargs=function[1]
            except:fargs=list()
            try:fproc=function[2]
            except:fproc=1
            for i in range(fproc):
                process=ExtProcess(event,target=fname,args=fargs)
                process.start()
                processes[process.pid]=process
        event.wait()
        for process in processes.values():
            process.terminate()
        for process in processes.values():
            process.join()

file: w_Recorder.py

desc:函数'capture'用于获取截图

from PIL import ImageGrab
import time

class Recorder(object):
    def capture(self):
        ImageGrab.grab().save("{f}.{e}".format(f=time.time(),e="png"))

file: w_Decorators.py

desc:并行运行给定函数以及类'Recorder'的方法'capture'

from w_Recorder import Recorder
from w_PythonHelper import PythonHelper

def check(function):
    def wrapper(*args):
        try:
            recorder=Recorder()
            PythonHelper.run_in_parallel([function,args],[recorder.capture])
            print("success")
        except Exception as e:
            print("failure: {}".format(e))
        return function
    return wrapper

file: w_Logger.py

desc:主程序(生成错误)

from w_Decorators import check
import time

class Logger(object):

    @check
    def run_testcase(self):
        # example function (runtime: 20s)
        for i in range(20):
            print("number: {}".format(i))
            time.sleep(1)

    def run_logger(self):
        self.run_testcase()


if __name__=="__main__":
    logger=Logger()
    logger.run_logger()

file: w_Logger.py

desc:主程序(核心工作)

from w_PythonHelper import PythonHelper
from w_Recorder import Recorder
import time

class Logger(object):

    def run_testcase(self):
        # example function (runtime: 20s)
        for i in range(20):
            print("number: {}".format(i))
            time.sleep(1)

    def run_logger(self):
        recorder=Recorder()
        PythonHelper.run_in_parallel([self.run_testcase],[recorder.capture])

if __name__=="__main__":
    logger=Logger()
    logger.run_logger()

在这两种情况下,这些相同的方法有何不同？

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编辑:有没有人有想法解决这个问题(这是这个Python的错误)？如果没有,也许有人知道在应用程序运行时捕获屏幕截图的好方法？

实际上我发现了类似的问题:multiprocessing.Process子类适用于Linux而不适用于Windows

答案是:To fix this, you can remove the process member.,但我怎么能为我的例子做这件事.

在调试错误时调用发生process.start()在run_in_parallel(*functions)

---

EDIT2:像ivan_pozdeev写道:我可以使用包装器作为函数,但不能将它用作装饰器.我有很多由这个装饰器装饰的函数,最简单的方法是在装饰器里面使用多处理.但不幸的是我无法解决这个问题.也许有人已经解决了类似的问题.任何暗示我都会感激不尽.

'run_in_parallel'功能就像我想要的那样.两个或多个函数并行运行,第一个函数完成,强制终止第二个函数.当我调用包装器(函数,*args)然后函数工作正常,当我把这个机制放在装饰器里面时我得到'不能发痒的功能......它没有被发现'错误.细节可以在上面找到

我的追溯:

Traceback (most recent call last):
  File "C:\Interpreters\Python32\lib\pickle.py", line 679, in save_global
    klass = getattr(mod, name)
AttributeError: 'module' object has no attribute 'run_testcase'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\EskyTests\w_Logger.py", line 19, in <module>
    logger.run_logger()
  File "C:\EskyTests\w_Logger.py", line 14, in run_logger
    self.run_testcase()
  File "C:\EskyTests\w_Decorators.py", line 14, in wrapper
    PythonHelper.run_in_parallel([function,args],[recorder.capture])
  File "C:\EskyTests\w_PythonHelper.py", line 25, in run_in_parallel
    process.start()
  File "C:\Interpreters\Python32\lib\multiprocessing\process.py", line 130, in start
    self._popen = Popen(self)
  File "C:\Interpreters\Python32\lib\multiprocessing\forking.py", line 267, in __init__
    dump(process_obj, to_child, HIGHEST_PROTOCOL)
  File "C:\Interpreters\Python32\lib\multiprocessing\forking.py", line 190, in dump
    ForkingPickler(file, protocol).dump(obj)
  File "C:\Interpreters\Python32\lib\pickle.py", line 237, in dump
    self.save(obj)
  File "C:\Interpreters\Python32\lib\pickle.py", line 344, in save
    self.save_reduce(obj=obj, *rv)
  File "C:\Interpreters\Python32\lib\pickle.py", line 432, in save_reduce
    save(state)
  File "C:\Interpreters\Python32\lib\pickle.py", line 299, in save
    f(self, obj) # Call unbound method with explicit self
  File "C:\Interpreters\Python32\lib\pickle.py", line 623, in save_dict
    self._batch_setitems(obj.items())
  File "C:\Interpreters\Python32\lib\pickle.py", line 656, in _batch_setitems
    save(v)
  File "C:\Interpreters\Python32\lib\pickle.py", line 299, in save
    f(self, obj) # Call unbound method with explicit self
  File "C:\Interpreters\Python32\lib\pickle.py", line 683, in save_global
    (obj, module, name))
_pickle.PicklingError: Can't pickle <function run_testcase at 0x00000000027725C8>: it's not found as __main__.run_testcase

Answer 1

很棘手，但我认为发生的情况是check在定义类时存储对未绑定方法的引用。self.run_testcase当您调用 时，工作示例使用对绑定方法的引用run_logger。

我认为最好的办法是尝试创建run_testcase一个顶级函数，而不是一个类的方法。

此外，您的capture函数可能不会执行您期望的操作 - 定义函数时将存储当前时间，并且每个屏幕截图都将保存在前一个屏幕截图之上。您可能想time.time()在函数内部调用。