#!/usr/bin/env python
# -*- coding: iso-8859-1 -*-
################################################################################
#
# Decorator @threadmethod(sec), makes decorated method calls to always
# execute in a separate new thread with a specified timeout, propagating
# exceptions, as well as a result.
# Dmitry Dvoinikov <dmitry@targeted.org>
#
# from threadmethod import *
#
# class NetworkedSomething(object):
# @threadmethod(10.0)
# def connect(self, host, port):
# ... this could take long long time ...
#
# # the following call throws ThreadMethodTimeoutError upon a 10 sec. timeout
# NetworkedSomething().connect("123.45.67.89", 1234). Similarly,
#
# @threadmethod()
# def foo():
# ...
#
# makes foo() an async method, which just executes in a new separate thread
# each time, but that thread is not waited for, it's just launched to execute
# in parallel. Besides, in the latter case foo() returns a reference to the
# created thread, so that it can be join()ed.
#
################################################################################
__all__ = [ "threadmethod", "ThreadMethodTimeoutError" ]
################################################################################
class ThreadMethodTimeoutError(Exception): pass
################################################################################
from threading import Thread
class ThreadMethodThread(Thread):
"ThreadMethodThread, daemonic descendant class of threading.Thread which " \
"simply runs the specified target method with the specified arguments."
def __init__(self, target, args, kwargs):
Thread.__init__(self)
self.setDaemon(True)
self.target, self.args, self.kwargs = target, args, kwargs
self.start()
def run(self):
try:
self.result = self.target(*self.args, **self.kwargs)
except Exception, e:
self.exception = e
except:
self.exception = Exception()
else:
self.exception = None
################################################################################
def threadmethod(timeout = None):
"@threadmethod(timeout), decorator function, returns a method wrapper " \
"which runs the wrapped method in a separate new thread."
def threadmethod_proxy(method):
if hasattr(method, "__name__"):
method_name = method.__name__
else:
method_name = "unknown"
def threadmethod_invocation_proxy(*args, **kwargs):
worker = ThreadMethodThread(method, args, kwargs)
if timeout is None:
return worker
worker.join(timeout)
if worker.isAlive():
raise ThreadMethodTimeoutError("A call to %s() has timed out"
% method_name)
elif worker.exception is not None:
raise worker.exception
else:
return worker.result
threadmethod_invocation_proxy.__name__ = method_name
return threadmethod_invocation_proxy
return threadmethod_proxy
################################################################################
if __name__ == "__main__": # run self-tests
print "self-testing module threadmethod.py:"
from threading import currentThread
mainthread = currentThread()
@threadmethod(5)
def tryme():
assert currentThread() is not mainthread
tryme()
@threadmethod(5)
def foo(a, b, c):
return a + b + c
assert foo(1, 2, 3) == 6
@threadmethod(5)
def foo(*args):
assert args == ("foo", )
return args[0]
assert foo("foo") == "foo"
@threadmethod(5)
def foo(**kwargs):
assert kwargs == { "foo" : "bar" }
return kwargs["foo"]
assert foo(foo = "bar") == "bar"
@threadmethod(5)
def foo(a, b, *args, **kwargs):
assert a == 1 and b == "foo" and args == ("bar", ) and kwargs == { "biz" : "baz" }
assert foo(1, "foo", "bar", biz = "baz") is None
from time import sleep
class bar(object):
@threadmethod(3)
def __init__(self, timeout):
sleep(timeout)
@threadmethod(1)
def throw(self, e):
raise e
try:
bar(5)
except ThreadMethodTimeoutError:
pass
else:
assert False, "Constructor should have timed out"
try:
bar(1).throw(IOError("fatal"))
except IOError, e:
assert str(e) == "fatal"
else:
assert False, "Expected IOError(\"fatal\")"
x = 0
@threadmethod()
def async():
global x
sleep(0.25)
x += 1
async()
while x == 0:
pass
@threadmethod()
def foo():
sleep(1.0)
foo().join()
print "ok"
################################################################################
