After some work ... I've taken Laszlo's suggestion of using Value
(shared memory) objects
to share state between the -pseudo- Process (manager) object and it's
underlying multiprocessing.Process
instance (and subsequent process):
Here is the code:
----------------------------------------
#!/usr/bin/env python
import os
from time import sleep
from threading import activeCount as threads
from threading import Thread as _Thread
from multiprocessing import Value
from multiprocessing import Process as _Process
from multiprocessing import active_children as processes
class Process(object):
def __init__(self, *args, **kwargs):
super(Process, self).__init__(*args, **kwargs)
self.running = Value("b", False)
self.thread = _Thread(target=self.run)
self.process = _Process(target=self._run, args=(self.running,))
def _run(self, running):
self.thread.start()
try:
while running.value:
try:
sleep(1)
print "!"
except SystemExit:
running.acquire()
running.value = False
running.release()
break
except KeyboardInterrupt:
running.acquire()
running.value = False
running.release()
break
finally:
running.acquire()
running.value = False
running.release()
self.thread.join()
def start(self):
self.running.acquire()
self.running.value = True
self.running.release()
self.process.start()
def run(self):
pass
def stop(self):
print "%s: Stopping ..." % self
self.running.acquire()
self.running.value = False
self.running.release()
def isAlive(self):
return self.running.value
class A(Process):
def run(self):
while self.isAlive():
sleep(5)
self.stop()
a = A()
a.start()
N = 0
while a.isAlive():
sleep(1)
print "."
print "threads: %d" % threads()
print "processes: %d" % len(processes())
print "DONE"
----------------------------------------
Here is the result of running this:
----------------------------------------
$ python test3.py
!
.
threads: 1
processes: 1
.
threads: 1
processes: 1
!
!
.
threads: 1
processes: 1
.
threads: 1
processes: 1
!
.
threads: 1
processes: 1
!
<__main__.A object at 0x80de42c>: Stopping ...
!
.
threads: 1
processes: 0
DONE
----------------------------------------
This appears to work as I intended.
Thoughts / Comments ?
cheers
James
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