how to query/setting variable in one python process form another python process?

Question

Python snippet A :

import time
class task:
 def __init__(self): 
 self.progress_percent = 0
 def working(self):
 self.progress_percent = self.progress_percent + 1 
task1 = task()
task2 = task()
while True:
 time.sleep(1)
 task1.working()
 task2.working() 
 print task1.progress_percent
 print task2.progress_percent

How to query or even setting task1.progress_percent or task2.progress_percent runtime from another individual python process? (not pdb)

Thank you.

Answer 1

You can use multiprocessing.Process and Condition to do that. Please, try this code:

import multiprocessing
import time
class Task(multiprocessing.Process):
 counter = 0
 name = None
 event = None
 another_tasks = set()
 def __init__(self, mgr_dict, cond): 
 super(Task, self).__init__()
 self.mgr_dict = mgr_dict
 self.cond = cond
 cls = self.__class__
 cls.counter += 1
 self.name = '{} {}'.format(cls.__name__, cls.counter)
 self.mgr_dict[self.name] = 0
 def value(self):
 return self.mgr_dict[self.name]
 def run(self):
 while True:
 with self.cond:
 self.cond.wait()
 self.mgr_dict[self.name] += 1
class SubTask(Task):
 pass
class MainTask(Task):
 subtasks = set()
 def working(self):
 with self.cond:
 self.cond.notify_all()
 def start(self):
 super(MainTask, self).start()
 for subtask in self.subtasks:
 subtask.start()
 def create_subtask(self):
 subtask = SubTask(self.mgr_dict, condition)
 self.subtasks.add(subtask)
 def join(self):
 self.mgr_dict[self.name]
 def shutdown(self):
 self.exit.set()
event = multiprocessing.Event()
if __name__ == '__main__':
 mgr = multiprocessing.Manager()
 mgr_dict = mgr.dict()
 condition = multiprocessing.Condition()
 task1 = MainTask(mgr_dict, condition)
 subtask1 = task1.create_subtask()
 subtask2 = task1.create_subtask()
 subtask3 = task1.create_subtask()
 subtask4 = task1.create_subtask()
 subtask5 = task1.create_subtask()
 task1.start()
 while task1.value() < 100:
 time.sleep(1)
 task1.working()
 print mgr_dict

The result:

{'MainTask 1': 0, 'SubTask 1': 0, 'SubTask 2': 0, 'SubTask 3': 0, 'SubTask 4': 0, 'SubTask 5': 0}
{'MainTask 1': 1, 'SubTask 1': 1, 'SubTask 2': 1, 'SubTask 3': 1, 'SubTask 4': 1, 'SubTask 5': 1}
.
.
.
{'MainTask 1': 100, 'SubTask 1': 100, 'SubTask 2': 100, 'SubTask 3': 100, 'SubTask 4': 100, 'SubTask 5': 100}

• K. C: thanks for the reply, however what I want to know whether I can query task.progress_percent from another individual "python process", sort of "IPC" between processes
• arkadyzalko: Ops.. Sorry =) You can do that with Shared Namespaces. I can make a example if you want.
• K. C: appreciated if you can show an example, more, can 'Shared Namespaces' working for the different python process not spawned by progress A?
• arkadyzalko: You should have main process. But all progress can be inside Process. Just a moment, I'm going to finish the example =)
• K. C: thank you. And I find module 'rpyc' or 'pyro' can be useful to handle both RPC and IPC access problem.