I am having issues with my halt_listener thread. I can start import_1 but it will not spawn a halt_listener thread. I am patterning this after known good code, the only difference was in the last iteration the halt_listener got fed a pipe instead of a queue.
class test_imports:#Test classes remove
alive = {'import_1': True, 'import_2': True};
def halt_listener(self, control_Queue, thread_Name, kill_command):
while True:
print ("Checking queue for kill")
isAlive = control_queue.get()
print ("isAlive", isAlive)
if isAlive == kill_command:
print ("kill listener triggered")
self.alive[thread_Name] = False;
return
def import_1(self, control_Queue, thread_Number):
print ("Import_1 number %d started") % thread_Number
t = Thread(target=test_imports.halt_listener, args=(control_Queue, 'import_1', 't1kill'))
count = 0
global alive
run = test_imports.alive['import_1'];
while run:
print ("Thread type 1 number %d run count %d") % (thread_Number, count)
count = count + 1
print ("Test Import_1 ", run)
run = self.alive['import_1'];
print ("Killing thread type 1 number %d") % thread_Number
def import_2(self, control_queue, thread_number):
print ("Import_2 number %d started") % thread_number
count = 1
while True:
alive = control_queue.get()
count = count + 1
if alive == 't2kill':
print ("Killing thread type 2 number %d") % thread_number
return
else:
print ("Thread type 2 number %d run count %d") % (thread_number, count)
Anyone have any pointers to where I am going wrong.
You never call t.start() to actually start the thread.
everything is okay, you just have to add t.start() to start your thread
t = Thread(target=test_imports.halt_listener, args=(control_Queue, 'import_1', 't1kill'))
t.start()
Related
I have a python script that uses threading, here is my code:
def main():
ip_list = get_ip_list() #['ip1', 'ip2'..., 'ipn'] thousands
for x in ip_list:
q.put(x)
threads = []
threads_num = 50
for x in range(threads_num):
w = Worker(q, stantard_config_to_dict, id_dict, logger,ip_position)
threads.append(w)
w.start()
for w in threads:
w.join()
logger.debug('End of main thread, exit')
print 'End of main thread, exit'
def run(self):
while 1:
try:
ip = self.queue.get(False)
self.logger.debug('%s get %s from queue, left %s in queue' % (self.getName(), ip, self.queue.qsize()))
self.get_inter_conf(ip)
except Queue.Empty:
self.logger.debug('queue is empty, exit')
break
self.logger.info("%s finished" % (self.getName()))
The string 'End of main thread' doesn't get printed right now, only when I change the number of items in ip_list it gets printed.
Why does this happen?
I am having issues with this multiprocess script I modeled it after the one I found here
http://broadcast.oreilly.com/2009/04/pymotw-multiprocessing-part-2.html
class test_imports:#Test classes remove
def import_1(self, control_queue, thread_number):
print ("Import_1 number %d started") % thread_number
run = True
count = 1
while run:
alive = control_queue.get()
if alive == 't1kill':
print ("Killing thread type 1 number %d") % thread_number
run = False
break
print ("Thread type 1 number %d run count %d") % (thread_number, count)
count = count + 1
def worker_generator(control_queue, threadName, runNum):
if threadName == 'one':
print ("Starting import_1 number %d") % runNum
p = Process(target=test_import.import_1, args=(control_queue, runNum))
p.start()
if __name__ == '__main__':
# Establish communication queues
control = multiprocessing.Queue()
runNum = int(raw_input("Enter a number: "))
threadNum = int(raw_input("Enter number of threads: "))
threadName = raw_input("Enter number: ")
thread_Count = 0
print ("Starting threads")
for i in range(threadNum):
worker_generator(control, threadName, i)
thread_Count = thread_Count + 1
time.sleep(runNum)#let threads do their thing
print ("Terminating threads")
for i in range(thread_Count):
control.put("t1kill")
control.put("t2kill")
This is the error I get when I run it:
Traceback (most recent call last):
File "multiQueue.py", line 62, in <module>
worker_generator(control, threadName, i)
File "multiQueue.py", line 34, in worker_generator
p = Process(target=test_import.import_1, args=(control_queue, runNum))
NameError: global name 'Process' is not defined`
I know where it is, but I took that process call from known good code so I don't think it is a syntax error. Any help?
You probably did import multiprocessing. Which is fine, because in your code, you actually did:
multiprocessing.Queue()
But, when doing Process(), you forgot to put multiprocessing. before it.
However, you can also fix this by importing the classes directly:
from multiprocessing import Queue, Process
But then you would have to change multiprocessing.Queue() to just Queue()
Normally this is due to a missing module import.
Did you import multiprocessing?
The code I have is:
import multiprocessing
import time
class test_imports:#Test classes remove
def import_1(self, control_queue, thread_number):
print ("Import_1 number %d started") % thread_number
run = True
count = 1
while run:
alive = control_queue.get()
if alive == 't1kill':
print ("Killing thread type 1 number %d") % thread_number
run = False
break
print ("Thread type 1 number %d run count %d") % (thread_number, count)
count = count + 1
def worker_generator(control_queue, threadName, runNum):
if threadName == 'one':
print ("Starting import_1 number %d") % runNum
p = multiprocessing.Process(target=test_imports.import_1, args=(control_queue, runNum))
p.start()
if __name__ == '__main__':
# Establish communication queues
control = multiprocessing.Queue()
runNum = int(raw_input("Enter a number: "))
threadNum = int(raw_input("Enter number of threads: "))
threadName = raw_input("Enter name: ")
thread_Count = 0
print ("Starting threads")
for i in range(threadNum):
worker_generator(control, threadName, i)
thread_Count = thread_Count + 1
time.sleep(runNum)#let threads do their thing
print ("Terminating threads")
for i in range(thread_Count):
control.put("t1kill")
control.put("t2kill")
This code is to start and stop multiple copies of various different thread types. I will preface this with saying I tried using pipes to control the threads but keep getting random memory errors to do with the pipes. This is a prototype of a factory to produce several copies of multiple thread types, so a queue method didn't seem practical to me either though if there is something I am missing I am all ears. So my newest plan is to use a global dictionary with a different entry for every thread and thread kill condition. ie sub[Alive] subKill["kill"]
Yet for some reason the control_listener thread spawned by the processes wont trigger the kill condition and wont read the global variable.
from multiprocessing import Process, Pipe
from threading import Thread
import time
alive = {'subAlive': True, 'subKill': "Alive", 'testAlive': True, 'testKill': "Alive"};
def control_listener(aliveFlag, threadAlive): #listens for kill from main
global alive
while True:
data = alive[aliveFlag];
print "Thread", alive[threadAlive];
print "Thread status", alive[aliveFlag];
if data == "kill":
print "Killing"
alive[threadAlive] = False; #value for kill
print "testListner alive %s" % threadAlive, alive[threadAlive];
print "deactivating %s" % threadAlive, alive['aliveFlag'];
break
def subprocess(aliveFlag, threadNum, threadAlive):
t = Thread(target=control_listener, args=(aliveFlag, threadAlive))
count = 0
threadVal = threadNum
t.start()
run = alive['subAlive'];
while run == True:
print "Thread alive %s" % alive['aliveFlag'];
print "Thread %d Run number = %d" % (threadVal, count), alive['subAlive'];
count = count + 1
run = alive['subAlive'];
def testprocess(aliveFlag, threadNum, threadAlive):
t = Thread(target=control_listener, args=(aliveFlag, threadAlive))
count = 0
threadVal = threadNum
t.start()
run = alive['testAlive'];
while run == True:
print "This is a different thread %d Run = %d" % (threadVal, count)
count = count + 1
run = alive['testAlive'];
runNum = int(raw_input("Enter a number: "))
threadNum = int(raw_input("Enter number of threads: "))
print "Starting threads"
for i in range(threadNum):
p = Process(target=subprocess, args=('subKill', i, 'subAlive'))
p.start()
print "Subprocess started"
for i in range(threadNum):
p2 = Process(target=testprocess, args=('subKill', i, 'testAlive'))
p2.start()
print "Testproccess started"
print "Starting run"
time.sleep(runNum)
print "Terminating Subprocess run"
for i in range(threadNum):
alive['subKill'] = "kill";
print "Subkill = %s" % alive['subKill'];
print "Testprocess termination alive", alive['subAlive'];
print "Terminating Testprocess run"
for i in range(threadNum):
alive['subKill'] = "kill";
print "Testprocess termination alive", alive['subAlive'];
p.join()
p2.join()
I have this script and it does work it has 2 separate processes that spawn listener threads to kill the process when kill is sent to the listener via a pipe.
from multiprocessing import Process, Pipe
from threading import Thread
import time
subAlive = True
testAlive = True
def sub_listener(conn): #listens for kill from main
global subAlive
while True:
data = conn.recv()
if data == "kill":
subAlive = False #value for kill
break
def test_listener(conn): #listens for kill from main
global testAlive
while True:
data = conn.recv()
if data == "kill":
testAlive = False #value for kill
break
def subprocess(conn, threadNum):
t = Thread(target=sub_listener, args=(conn,))
count = 0
threadVal = threadNum
t.start()
while subAlive:
print "Thread %d Run number = %d" % (threadVal, count)
count = count + 1
def testprocess(conn, threadNum):
t = Thread(target=test_listener, args=(conn,))
count = 0
threadVal = threadNum
t.start()
while testAlive:
print "This is a different thread %d Run = %d" % (threadVal, count)
count = count + 1
sub_parent, sub_child = Pipe()
test_parent, test_child = Pipe()
runNum = int(raw_input("Enter a number: "))
threadNum = int(raw_input("Enter number of threads: "))
print "Starting threads"
for i in range(threadNum):
p = Process(target=subprocess, args=(sub_child, i))
p.start()
print "Subprocess started"
for i in range(threadNum):
p2 = Process(target=testprocess, args=(test_child, i))
p2.start()
print "Testproccess started"
print "Starting run"
time.sleep(runNum)
print "Terminating Subprocess run"
for i in range(threadNum):
sub_parent.send("kill") #sends kill to listener
print "Terminating Testprocess run"
for i in range(threadNum):
test_parent.send("kill") #sends kill to listener
p.join()
p2.join()
Id like to not need a separate listener function hard coded for every process I call. I was thinking about passing global variables when the thread is spawned. The global variables are really the only differences between the listener functions. Thanks guys!
You can access globals through the globals() dictionary.
>>> foo = 'value'
>>> def change(name):
... globals()[name] = 'changed'
...
>>> change('foo')
>>> foo
'changed'
but I would suggest:
alive = {}
def sub_listener(conn, key): #listens for kill from main
while True:
data = conn.recv()
if data == "kill":
alive[key] = False #value for kill
break
e.g.
from multiprocessing import Process, Pipe
from threading import Thread
import time
alive = {
'sub': 1,
'test': 1,
}
def listener_factory(key):
def listener(conn): #listens for kill from main
while True:
data = conn.recv()
if data == "kill":
alive[key] = False #value for kill
break
return listener
def process_factory(key):
listener = listener_factory(key)
def subprocess(conn, threadNum):
t = Thread(target=listener, args=(conn,))
count = 0
threadVal = threadNum
t.start()
while alive[key]:
print "Thread[%s] %d Run number = %d" % (key, threadVal, count)
count = count + 1
return subprocess
def main():
sub_parent, sub_child = Pipe()
test_parent, test_child = Pipe()
runNum = int(raw_input("Enter a number: "))
threadNum = int(raw_input("Enter number of threads: "))
print "Starting threads"
for i in range(threadNum):
p = Process(target=process_factory('sub'), args=(sub_child, i))
p.start()
print "Subprocess started"
for i in range(threadNum):
p2 = Process(target=process_factory('test'), args=(test_child, i))
p2.start()
print "Testproccess started"
print "Starting run"
time.sleep(runNum)
print "Terminating Subprocess run"
for i in range(threadNum):
sub_parent.send("kill") #sends kill to listener
print "Terminating Testprocess run"
for i in range(threadNum):
test_parent.send("kill") #sends kill to listener
p.join()
p2.join()
if __name__ == '__main__':
main()
I'm working on a script, which will print a timer and was trying to reuse a function like this:
def timer(m,x):
for i in range(1,x):
sys.stdout.write('\r%s\b%d' % (m,i))
sys.stdout.flush()
sleep(1)
sys.stdout.write('\r \b')
Now, the part of the script, where I want a timer to be displayed is like this:
host_alive = "ping -c1 myServer"
cmdStat, cmdOut = commands.getstatusoutput(host_alive)
while True:
if cmdStat != 0:
(cmdStat,cmdOut) = commands.getstatusoutput(host_alive)
print "Still NOT ready!!"
else:
break
How can I print a timer without specifying a range()? Is there any workaround?
Cheers!!
def timer(m):
i = 0
while True:
sys.stdout.write('\r%s\b%d' % (m,i))
sys.stdout.flush()
sleep(1)
sys.stdout.write('\r \b')
i = i + 1
First of all commands module is deprecated and replaced by subprocess module.
Secondly, to represent infinity in python you can use float('inf'). Its symbolic that you are referring to infinity.
def timer(m):
i = 0
while i<float('inf'): #this is symbolic and in essence similar to while True
sys.stdout.write('\r%s\b%d' % (m,i))
sys.stdout.flush()
sleep(1)
sys.stdout.write('\r \b')
i += 1
A while loop would probably be a better option here. Ex:
def timer(max):
while counter > 0:
print '%d seconds remain' % max
sleep(1)
max -= 1