Im trying to return a "snapshot" of information from a function running in a thread with python. I thought it would be easy, but google doesent make any sens.
import thread
import sys
import time
def counter():
count = 0
while 1:
count = count +1
# Hi screen
print('Welcome to thread example!\n')
# Avalibel commands
print('Enter [quit] to exit. enter [status] for count status')
C = thread.start_new_thread(counter ,())
while 1:
try:
command = raw_input('Command: ')
if command == 'quit':
sys.exit()
elif command == 'status':
print(time.ctime())
print(C.count + '\n')
else:
print('unknown command. [quit] or [satus]')
except KeyboardInterrupt:
print "\nKeybord interrupt, exiting gracefully anyway."
sys.exit()
This above example gives me AttributeError: 'int' object has no attribute 'count', but i have tried a few "solutions" with different no success.
In this example i want counter() to run until i enter quit. A little output example:
Welcome to thread example!
Enter [quit] to exit. enter [status] for count status
>>> Command: status
Thu Feb 25 09:42:43 2016
123567
>>> Command: status
Thu Feb 25 10:0:43 2016
5676785785768568795
Question:
How do i return a "snapshot" value from def counter?
If i let this run for a couple of hours, will i have a memory issue?
You can do it by creating your custom Thread class. But keep in mind this infinite loop will eat up your CPU core on which this thread will be running on.
class MyCounter(threading.Thread):
def __init__(self, *args, **kwargs):
super(MyCounter, self).__init__()
self.count = 0
self._running = True
def run(self):
while self._running:
self.count += 1
def quit(self):
self._running = False
C = MyCounter()
C.start()
while 1:
try:
command = raw_input('Command: ')
if command == 'quit':
C.quit()
sys.exit()
elif command == 'status':
print(time.ctime())
print(C.count + '\n')
else:
print('unknown command. [quit] or [satus]')
except KeyboardInterrupt:
print "\nKeybord interrupt, exiting gracefully anyway."
sys.exit()
Related
I am writing a program which constantly checks if certain IP adresses are connected to the network. If they are, nothing happens. If they are not connected for a certain time, an action is triggered.
My script works as intended as far as I can tell, however when I try to exit it using ctrl+c it simply doesnt stop.
I guess it has something to do with the threading that I am using, but I cant figure out what exactly it is.
This is my code so far:
import os
import time
from threading import Timer, Thread
import json
with open("ip_adresses.json", "r") as f:
ip_adresses_dict = json.load(f)
def timeout():
print("ACTION IS TRIGGERED")
# dummy Timer thread
print("dummy timer created")
t = Timer(999999999, timeout)
t.daemon = True
try:
while True:
ip_adress_reachable = []
for key, value in ip_adresses_dict.items():
if os.system(f"ping -c 1 -W 1 {value} > /dev/null") is 0: # this means its reachable
ip_adress_reachable.append(True)
else:
ip_adress_reachable.append(False)
print(ip_adress_reachable)
# if no ip adresses are reachable and no timer running, start a timer.
if any(ip_adress_reachable) == False and t.is_alive() == False:
print("starting a new thread")
t = Timer(15, timeout)
t.daemon = True
t.start()
# If in the meantime ip adress gets reachable cancel the timer.
elif any(ip_adress_reachable) == True and t.is_alive() == True:
# cancel the timer
print("timer was canceled")
t.cancel()
except KeyboardInterrupt:
print("quitting")
t.join(1)
I am kinda lost, because I though that deamon threads would stop after the main loop is done (i.e. after I press ctr+c)
If somebody could help me out, I would be very grateful.
After testing I found that all problem makes os.system() which catchs Ctrl+C to stop process running in os.system() - ping - and it doesn't send this information to Python.
If you run ping longer and you skip /dev/null
os.system(f"ping -c 5 -W 1 {value}")
then you will see that Ctrl+C stops ping
If I uses subprocess then I don't have this problem.
subprocess.call(f"ping -c 1 -W 1 {value} > /dev/null", shell=True)
Code which I used for test on Linux Mint 20 (based on Ubuntu 20.04)
#import os
import time
from threading import Timer, Thread
#import json
import subprocess
#with open("ip_adresses.json", "r") as f:
# ip_adresses_dict = json.load(f)
ip_adresses_dict = {
'x': '192.168.0.1',
'y': '192.168.0.2',
'z': '192.168.0.3',
}
def timeout():
print("ACTION IS TRIGGERED")
# dummy Timer thread
print("dummy timer created")
t = Timer(999999999, timeout)
t.daemon = True
try:
while True:
ip_adress_reachable = []
for key, value in ip_adresses_dict.items():
print('[DEBUG] start process')
#result = os.system(f"ping -c 1 -W 1 {value} > /dev/null")
#result = os.system(f"ping -c 5 -W 1 {value}")
result = subprocess.call(f"ping -c 1 -W 1 {value} > /dev/null", shell=True)
print('[DEBUG] end process')
ip_adress_reachable.append( result == 0 )
print(ip_adress_reachable)
# if no ip adresses are reachable and no timer running, start a timer.
if any(ip_adress_reachable) is False and t.is_alive() is False:
print("starting a new thread")
t = Timer(15, timeout)
t.daemon = True
t.start()
# If in the meantime ip adress gets reachable cancel the timer.
elif any(ip_adress_reachable) is True and t.is_alive() is True:
# cancel the timer
print("timer was canceled")
t.cancel()
except KeyboardInterrupt:
print("quitting")
if t.is_alive():
t.join(1)
Doc: Replacing os.system()
I have a program that is supposed to send a few data points over a serial connection to an arduino which will control some motors to move. I can send the control signals individually as well as by txt file which will run repeatedly until the file is complete. While running a txt file, I want to be able to exit the loop like a pause or stop button. I think the best way to do that is via a thread that I can close. I have never done any threading before and my rudimentary attempts have not worked. Here is the function that sends the file data.
def send_file():
# Global vars
global moto1pos
global motor2pos
# Set Ready value
global isready
# Get File location
program_file_name = file_list.get('active')
file_path = "/home/evan/Documents/bar_text_files/"
program_file = Path(file_path + program_file_name)
file = open(program_file)
pos1 = []
pos2 = []
speed1 = []
speed2 = []
accel1 = []
accel2 = []
for each in file:
vals = each.split()
pos1.append(int(vals[0]))
pos2.append(int(vals[1]))
speed1.append(int(vals[2]))
speed2.append(int(vals[3]))
accel1.append(int(vals[4]))
accel2.append(int(vals[5]))
# Send file values
try:
while isready == 1:
for i in range(len(pos1)):
print("Step: " + str(i+1))
data = struct.pack("!llhhhh", pos1[i], pos2[i], speed1[i], speed2[i], accel1[i], accel2[i])
ser.write(data)
try:
pos1time = abs(pos1[i]/speed1[i])
except:
pos1time = 0
try:
pos2time = abs(pos2[i]/speed2[i])
except:
pos2time = 0
time_array = (pos1time, pos2time)
time.sleep(max(time_array))
motor1pos = ser.readline()
motor2pos = ser.readline()
if i < (len(pos1)-1):
isready = ord(ser.read(1))
else:
isready = 0
except:
print("Error: data not sent. Check serial port is open")
Here is the threading command which I want the sendfile command to work from.
def thread():
try:
global isready
isready = 1
t = threading.Thread(name='sending_data', target=command)
t.start()
except:
print("Threading Error: you don't know what you are doing")
And here is the stop function I want the thread to be killed by:
def stop():
try:
global isready
isready = 0
t.kill()
except:
print("Error: thread wasn't killed")
I know you aren't supposed to kill a thread but the data isn't very important. Whats more important is to stop the motors before something breaks.
The button in tkinter is:
run_file_butt = tk.Button(master = file_frame, text = "Run File", command = thread)
When I click the button, the program runs but the stop function does nothing to stop the motion.
Question: run and kill a thread on a button press
There is no such a thing called .kill(....
Start making your def send_file(... a Thread object which is waiting your commands.
Note: As it stands, your inner while isready == 1: will not stop by using m.set_state('stop').
It's mandatory to start the Thread object inside:
if __name__ == '__main__':
m = MotorControl()
import threading, time
class MotorControl(threading.Thread):
def __init__(self):
super().__init__()
self.state = {'is_alive'}
self.start()
def set_state(self, state):
if state == 'stop':
state = 'idle'
self.state.add(state)
def terminate(self):
self.state = {}
# main function in a Thread object
def run(self):
# Here goes your initalisation
# ...
while 'is_alive' in self.state:
if 'start' in self.state:
isready = 1
while isready == 1:
# Here goes your activity
# Simulate activity
print('running')
time.sleep(2)
isready = 0
self.state = self.state - {'start'}
self.state.add('idle')
elif 'idle' in self.state:
print('idle')
time.sleep(1)
if __name__ == '__main__':
m = MotorControl()
time.sleep(2)
m.set_state('start')
time.sleep(3)
m.set_state('stop')
time.sleep(3)
m.set_state('start')
time.sleep(4)
m.terminate()
print('EXIT __main__')
Your tk.Button should look like:
tk.Button(text = "Run File", command = lambda:m.set_state('start'))
tk.Button(text = "Stop File", command = lambda:m.set_state('stop'))
tk.Button(text = "Terminate", command = m.terminate)
The answer I have gone with is simple due to my simple understanding of threading and unique circumstances with which I am using the threading. Instead of terminating the thread in a way I was hoping, I added another conditional statement to the sending line of the send_file function.
while isready == 1:
for i in range(len(pos1)):
if motorstop == False:
print("Step: " + str(i+1))
#data = struct.pack('!llllhhhhhhhh', pos1[i], pos2[i], pos3[i], pos4[i], speed1[i], speed2[i], speed3[i], speed[4], accel1[i], accel2[i], accel3[i], accel4[i])
data = struct.pack("!llhhhh", pos1[i], pos2[i], speed1[i], speed2[i], accel1[i], accel2[i])
ser.write(data)
else:
isready = 0
break
and I have updated my stop() func to the following:
def stop():
try:
global motorstop
global t
motorstop = True
t.join()
except:
print("Error: thread wasn't killed")
I'm not exactly sure how it works but it is much simpler than what was mentioned by #stovefl.
With this code, since the function is mostly just sleeping, it can run but it won't send any new information and then will .join() after the next iteration.
is there any way for ask question by if statement and after afew sec if user didnot give any answer , if state use a default answer?
inp = input("change music(1) or close the app(2)")
if inp = '1':
print("Music changed)
elif inp = '2':
print("good by")
in this case if user dont give any answer after 30 sec by default if statement choose number 3
from threading import Timer
out_of_time = False
def time_ran_out():
print ('You didn\'t answer in time') # Default answer
out_of_time = True
seconds = 5 # waiting time in seconds
t = Timer(seconds,time_ran_out)
t.start()
inp = input("change music(1) or close the app(2):\n")
if inp != None and not out_of_time:
if inp == '1':
print("Music changed")
elif inp == '2':
print("good by")
else:
print ("Wrong input")
t.cancel()
Timer Objects
This class represents an action that should be run only after a certain amount of time has passed — a timer. Timer is a
subclass of Thread and as such also functions as an example of
creating custom threads.
Timers are started, as with threads, by calling their start() method.
The timer can be stopped (before its action has begun) by calling the
cancel() method. The interval the timer will wait before executing its
action may not be exactly the same as the interval specified by the
user.
For example:
def hello():
print("hello, world")
t = Timer(30.0, hello)
t.start() # after 30 seconds, "hello, world" will be printed
class threading.Timer(interval, function, args=None, kwargs=None)
Create a timer that will run function with arguments args and keyword
arguments kwargs, after interval seconds have passed. If args is None
(the default) then an empty list will be used. If kwargs is None (the
default) then an empty dict will be used.
cancel()
Stop the timer, and cancel the execution of the timer’s action. This will only work if the timer is still in its waiting
stage.
Here's an alternative way to do it (python 3), using multiprocessing. Note, to get the stdin to work in the child process, you have to re open it first. I'm also converting the input from string to int to use with the multiprocessing value, so you might want to error check there as well.
import multiprocessing as mp
import time
import sys
import os
TIMEOUT = 10
DEFAULT = 3
def get_input(resp: mp.Value, fn):
sys.stdin = os.fdopen(fn)
v = input('change music(1) or close the app (2)')
try:
resp.value = int(v)
except ValueError:
pass # bad input, maybe print error message, try again in loop.
# could also use another mp.Value to signal main to restart the timer
if __name__ == '__main__':
now = time.time()
end = now + TIMEOUT
inp = 0
resp = mp.Value('i', 0)
fn = sys.stdin.fileno()
p = mp.Process(name='Get Input', target=get_input, args=(resp, fn))
p.start()
while True:
t = end - time.time()
print('Checking for timeout: Time = {:.2f}, Resp = {}'.format(t, resp.value))
if t <= 0:
print('Timeout occurred')
p.terminate()
inp = DEFAULT
break
elif resp.value > 0:
print('Response received:', resp.value)
inp = resp.value
break
else:
time.sleep(1)
print()
if inp == 1:
print('Music Changed')
elif inp == 2:
print('Good Bye')
else:
print('Other value:', inp)
I'm new to Python and have been googling for a couple of days and read all I can find on this forum. Might be that I don't understand it all but I haven't found a solution to my problem yet. Ask for forgiveness already if there's an answer already to my problem, then I haven't understood it.
I want to make a Pause function for my program Tennismatch. The program will when it's being run print the score of a tennis match like this: "15-0, 15-15 etc ongoing till the match ends. It will print the score line by line.
I want the user to be able to pause after x number of balls, games, etc. So I don't know when the user wants to pause and after the user has paused I want the user to be able to resume the tennismatch where it was.
Have seen the time.sleep() but as I have understood it you must know when you want to pause to use this and it also ain't an indefinetie pause like I want. With input() it's the same.
Am going to make a GUI later on when the code is finished. Happy for anything that leads me to solving my problem.
I use Windows and Python 3.42 and run the program in Shell.
A piece of the code (haven't written it all yet, it's more of a general situation when something is being printed line after line for some time and want to be able do pause in the CIL:
#self.__points = [0,0]
def playGame(self):
if self.server == True: #self.server is either True or False when someone calls playGame()
server = self.player_1.get_win_serve() #self.player_1 = an object of a class Player():
else:
server = self.player_2.get_win_serve() #get_win_serve() method returns the probability to win his serv (1-0)
while (0 < self.__points[0] - self.__points[1] >= 2 or 0 < self.__points[1] - self.__points[0] >= 2) and (self.__points[1] >= 4 or self.__points[0] >= 4):
x = random.uniform(0,1)
if x > 0 and x < server:
self.__points[0] += 1
else:
self.__points[1] += 1
# print('The score, by calling a score() function that I haven't written yet')
For dealing with events in main loop you need to make a separated thread which capture input or any other event.
import sys
from sys import stdin
from time import sleep
from threading import Thread
from Queue import Queue, Empty
def do_something():
sleep(1)
print 42
def enqueue_output(queue):
while True:
# reading line from stdin and pushing to shared queue
input = stdin.readline()
print "got input ", input
queue.put(input)
queue = Queue()
t = Thread(target=enqueue_output, args=(queue,))
t.daemon = True
t.start()
pause = False
try:
while True:
try:
command = queue.get_nowait().strip()
print 'got from queue ', command
except Empty:
print "queue is empty"
command = None
if command:
if command == 'p':
pause = True
if command == 'u':
pause = False
if not pause:
print pause
do_something()
except KeyboardInterrupt:
sys.exit(0)
I came up with the following.
while True:
try:
## Keep doing something here
## your regular code
print '.',
except KeyboardInterrupt:
## write or call pause function which could be time.sleep()
print '\nPausing... (Hit ENTER to continue, type quit to exit.)'
try:
response = raw_input()
if response.lower() == 'quit':
break
print 'Quitting...'
except KeyboardInterrupt:
print 'Resuming...'
continue
The Event loop might as well be the code I wrote with.
I don't see any user input so I assume that x emulates it. To pause the game if x < 0.1 and to unpause(/resume) it if x > 0.9, you could:
while your_condition(self.__points):
x = random.random()
if x < 0.1: # pause
self.pause()
elif x > 0.9: # resume
self.resume()
if self.is_paused:
continue # do nothing else only wait for input (`x`)
# assume your_condition() has no side-effects
# here's what the resumed version does:
print("...")
# change self.__points, etc
where pause(), resume(), is_paused() methods could be implemented as:
def __init__(self):
self.is_paused = False
def pause(self):
self.is_paused = True
def resume(self):
self.is_paused = False
as you can see the implementation is very simple.
I've made this little alarm clock with a little help from my brother. I tried it last night, with out the nonBlockingRawInput and that worked fine, but with the nonBlockingRawInput it didn't work. Today I've tried it but neither of them work! I will post the code with the nonBlockingRawInput and the "non" file. If you want the code without nonBlockingRawInput, just ask.
Thanks in advance.
alarm rpi.py:
import time
import os
from non import nonBlockingRawInput
name = input("Enter your name.")
print("Hello, " + name)
alarm_HH = input("Enter the hour you want to wake up at")
alarm_MM = input("Enter the minute you want to wake up at")
print("You want to wake up at " + alarm_HH + ":" + alarm_MM)
while True:
now = time.localtime()
if now.tm_hour == int(alarm_HH) and now.tm_min == int(alarm_MM):
print("ALARM NOW!")
os.popen("open mpg321 /home/pi/voltage.mp3")
break
else:
print("no alarm")
timeout = 60 - now.tm_sec
if nonBlockingRawInput('', timeout) == 'stop':
break
non.py:
import signal
class AlarmException(Exception):
pass
def alarmHandler(signum, frame):
raise AlarmException
def nonBlockingRawInput(prompt='', timeout=20):
signal.signal(signal.SIGALRM, alarmHandler)
signal.alarm(timeout)
try:
text = input(prompt)
signal.alarm(0)
return text
except AlarmException:
pass
signal.signal(signal.SIGALRM, signal.SIG_IGN)
return ''
I've been looking at your code for a while now. As far as I can understand you want to be able to run an alarm while also being able to type "stop" in the shell to end the program, to this end you can make the alarm a thread. The thread will check if its time to say "ALARM!" and open the mp3. If the user hasn't typed stop in the shell, the thread will sleep and check again later.
I essentially used your code and just put it into an alarm thread class:
import time
import os
import threading
class Alarm(threading.Thread):
def __init__(self, hours, minutes):
super(Alarm, self).__init__()
self.hours = int(hours)
self.minutes = int(minutes)
self.keep_running = True
def run(self):
try:
while self.keep_running:
now = time.localtime()
if (now.tm_hour == self.hours and now.tm_min == self.minutes):
print("ALARM NOW!")
os.popen("voltage.mp3")
return
time.sleep(60)
except:
return
def just_die(self):
self.keep_running = False
name = raw_input("Enter your name: ")
print("Hello, " + name)
alarm_HH = input("Enter the hour you want to wake up at: ")
alarm_MM = input("Enter the minute you want to wake up at: ")
print("You want to wake up at: {0:02}:{1:02}").format(alarm_HH, alarm_MM)
alarm = Alarm(alarm_HH, alarm_MM)
alarm.start()
try:
while True:
text = str(raw_input())
if text == "stop":
alarm.just_die()
break
except:
print("Yikes lets get out of here")
alarm.just_die()
It is worth noting, that when the thread is sleeping, with:
time.sleep(60)
And you typed stop in the shell the thread would have to wake up before it realised it was dead, so you could at worst end up waiting a minute for the program to close!
import winsound,time
a= int(input("Enter how many times I have beep :"))
b= int(input("Enter when to wake up (in seconds) :"))
time.sleep(b)
for i in range(a):
winsound.Beep(3000,100)
winsound.Beep(2500,100)
winsound.Beep(2000,100)
winsound.Beep(1000,100)
winsound.Beep(500,100)