Semaphore example in python

Semaphore in python

import threading

sem = threading.Semaphore() # or sem = threading.Semaphore(value=n)
sem.acquire()
# Your code here
sem.release()

Semaphore example in python

import threading
import time
import logging

logging.basicConfig(level=logging.DEBUG,
                    format='(%(threadName)-9s) %(message)s',)

class ThreadPool(object):
    def __init__(self):
        super(ThreadPool, self).__init__()
        self.active = []
        self.lock = threading.Lock()
    def makeActive(self, name):
        with self.lock:
            self.active.append(name)
            logging.debug('Running: %s', self.active)
    def makeInactive(self, name):
        with self.lock:
            self.active.remove(name)
            logging.debug('Running: %s', self.active)

def f(s, pool):
    logging.debug('Waiting to join the pool')
    with s:
        name = threading.currentThread().getName()
        pool.makeActive(name)
        time.sleep(0.5)
        pool.makeInactive(name)

if __name__ == '__main__':
    pool = ThreadPool()
    s = threading.Semaphore(3)
    for i in range(10):
        t = threading.Thread(target=f, name='thread_'+str(i), args=(s, pool))
        t.start()

Source: bogotobogo.com

Similar codes

6 votes260 views2 answers
Tkinter starter code
Python
0 vote212 views0 answer
Python
0 vote265 views3 answers
Find rules of decision tree python
Python
10 votes250 views6 answers
Progress bar python
Python
0 vote261 views1 answer
Print python reverse list
Python
0 vote275 views1 answer
Python matplotlib plot thickness
Python
1 vote260 views2 answers
Django client ip
Python Django
0 vote288 views1 answer
Django queryset to instance
Python Django
0 vote286 views1 answer
Check for strings as positive/negative - integer/float
Python
9 votes227 views3 answers
A value is trying to be set on a copy of a slice from a DataFrame.
Python