I have an application which, for convenience (I am reusing existing code) has been split into two different threads:
One of the things I want to perform from the interactive menu is to interact with the reactor. Once the user gives a specific command, I want to trigger a twisted event. Here is a very simplified version of my code:
from twisted.spread import pb
from twisted.internet import reactor
import threading
class TaskGatewaySupport():
def __init__(self):
self.object = None
self.factory = pb.PBClientFactory()
self.connector = None
def gotObject(self, object):
print 'gotObject > %s' % object
self.object = object
return object
def gotData(self, data):
return data
def gotNoObject(self, reason):
print 'gotNoObject > no object: %s' % reason
def connect(self, task_gateway_host = '127.0.0.1', task_gateway_pb_port = 8889):
print 'Connecting to %s:%s' % (task_gateway_host, task_gateway_pb_port)
self.connector=reactor.connectTCP(task_gateway_host, task_gateway_pb_port, self.factory)
d = self.factory.getRootObject()
d.addCallbacks(self.gotObject, self.gotNoObject)
return d
def Menu(task_gateway_support):
while True:
print '''
A) Connect
'''
choice = raw_input('Option > ')
if choice == 'A' : task_gateway_support.connect()
else : print "ERR: command not yet supported"
def version1():
task_gateway_support = TaskGatewaySupport()
thread = threading.Thread(target = Menu, args = (task_gateway_support,))
thread.start()
reactor.run()
def version2():
task_gateway_support = TaskGatewaySupport()
d = task_gateway_support.connect()
reactor.run()
if __name__ == '__main__':
version1()
As you can see, I am showing two different versions:
Running version2 will give this result:
Connecting to 127.0.0.1:8889
gotObject > <twisted.spread.pb.RemoteReference instance at 0x88e734c>
Which is what I was expecting.
Running version1 will give this:
A) Connect
Option > A
Connecting to 127.0.0.1:8889
A) Connect
Option > ^CgotNoObject > no object: [Failure instance: Traceback (failure with no frames): <class 'twisted.internet.error.ConnectError'>: An error occurred while connecting: [Failure instance: Traceback (failure with no frames): <class 'twisted.internet.error.ConnectionLost'>: Connection to the other side was lost in a non-clean fashion: Connection lost.
].
]
What I am doing here is selecting option A, and since nothing happens, I press ^C, which shows the error message.
I think the problems appear because I am sharing an object in two different threads, and I am trying to trigger the twisted events from the non-twisted thread. I was hoping that, since the object is shared, the reactor would be aware of anything hapening to the object.
So my main question is: how can I trigger twisted events from another thread?
You should avoid using threads for this. See User interaction in twisted process for information about how to accept user input in a single thread.
Apart from that, use reactor.callFromThread any time you want to call any Twisted API from a non-reactor thread.