multiprocessing - Process communication in Python

Question

What is the best way to establish communication between two processes in python? After some googling, I tried to do so:

parent_pipe, child_pipe = Pipe()
p = Process(target = instance_tuple.instance.run(), 
    args = (parent_pipe, child_pipe,))
p.start()

Sending data to the child process:

command = Command(command_name, args)
parent_pipe.send(command)

Process target function:

while True:
    if (self.parent_pipe.poll()):
        command = parent_pipe.recv()
        if (command.name == 'init_model'):
            self.init_model()
        elif (command.name == 'get_tree'):
            tree = self.get_fidesys_tree(*command.args)
            result = CommandResult(command.name, tree)
            self.child_pipe.send(result)
        elif(command.name == 'set_variable'):
            name = command.args[0]
            value = command.args[1]
            self.config[name] = value

But it doesn't seem to work (child process doesn't receive anything through parent_pipe). How can I fix it?

Thanks in advance.

Answer 1

You can have a look here : http://docs.python.org/library/multiprocessing.html#exchanging-objects-between-processes The solution is close to yours but seems easier.