multithreading - Overriding python threading.Thread.run()

Question

Given the Python documentation for Thread.run():

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

I have constructed the following code:

class DestinationThread(threading.Thread):
    def run(self, name, config):
        print 'In thread'

thread = DestinationThread(args = (destination_name, destination_config))
thread.start()

But when I execute it, I receive the following error:

Exception in thread Thread-1:
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/threading.py", line 522, in __bootstrap_inner
    self.run()
TypeError: run() takes exactly 3 arguments (1 given)

It seems I am missing something obvious, but the various examples I have seen work with this methodology. Ultimately I am trying to just pass the string and dictionary into the thread, if the Constructor is not the right way, but rather to make a new function to set the values prior to starting the thread, I am open to that.

Any suggestions on how to best accomplish this?

Answer 1

You really don't need to subclass Thread. The only reason the API supports this is to make it more comfortable for people coming from Java where that's the only way to do it sanely.

The pattern that we recommend you use is to pass a method to the Thread constructor, and just call .start().

 def myfunc(arg1, arg2):
     print 'In thread'
     print 'args are', arg1, arg2

 thread = Thread(target=myfunc, args=(destination_name, destination_config))
 thread.start()