I have a program, which needs to continuously run in the background, but be able to receive instructions to change. I have this thread running, which sends data to an Arduino and receives data back:
class receiveTemp (threading.Thread):
def __init__(self, out):
threading.Thread.__init__(self)
self.out = out
def run(self):
self.alive = True
try:
while self.alive:
rec = send("command")
self.out.write(rec)
except BaseException as Error:
print(Error)
pass
Now I need to change the command I send with an external program.
I tried using Pyro4, but I can not seem to get a Thread running on the server and then controlling it with the client.
Any ideas?
Scott Mermelstein's advice is good, I hope you will look into interprocess communications. But as a quick example to get you started, I would suggest modifying your code like this:
import threading
import queue
import sys
import time
class receiveTemp (threading.Thread):
def __init__(self, out, stop, q):
threading.Thread.__init__(self)
self.out = out
self.q = q
self.stop = stop
def run(self):
while not self.stop.is_set():
try:
cmd = self.q.get(timeout=1)
except queue.Empty:
continue
try:
rec = send(cmd)
self.out.write(rec)
except BaseException as Error:
print(Error)
pass
stop = threading.Event()
q = queue.Queue()
rt = receiveTemp(sys.stdout, stop, q)
rt.start()
# Everything below here is an example of how this could be used.
# Replace with your own code.
time.sleep(1)
# Send commands using put.
q.put('command0')
q.put('command1')
q.put('command2')
time.sleep(3)
q.put('command3')
time.sleep(2)
q.put('command4')
time.sleep(1)
# Tell the thread to stop by asserting the event.
stop.set()
rt.join()
print('Done')
This code uses a threading.Event as a signal to the thread that it should stop. It then uses a queue.Queue as a way to send commands to the thread from outside. You will need to use q.put(command) to add commands to the queue from outside the thread.
I didn't test this with an Arduino, I created my own version of send for testing that just returned the command.
