• target, the callable object to be invoked by the run() method
• args, the argument tuple for the target invocation
• kwargs, a dictionary of keyword arguments for the target invocation
• start(), start thread
• run(), implement callable object
• join(), wait until the thread terminates
• getName(), get thread's name

• currentThreading(), get the current thread

#!/usr/bin/python

import threading

def worker(i):
    """thread worker function"""
    print 'Hello World!', i

threads = []

#Create threads
for i in range(5):
    threads.append(threading.Thread(target=worker, args = (i, )));

#Start theads
for t in threads:
    t.start()

#Join theads
for t in threads:
    print 'Join', t.ident, t.getName()
    t.join()

print 'End of program'
			

#!/usr/bin/python

import threading
import logging

def worker(i):
    """thread worker function"""
    logging.debug(str(threading.currentThread().getName()) + ' Start ...');
    print 'Hello World!', i
    logging.debug(threading.currentThread().getName() + ' End ...');

logging.basicConfig(format='[%(levelname)s] (%(threadName)-10s): %(message)s', level=logging.DEBUG);
threads = []

#Create threads
for i in range(5):
    threads.append(threading.Thread(target=worker, args = (i, )));

#Start theads
for t in threads:
    t.start()

#Join theads
for t in threads:
    print 'Join', t.ident, t.getName()
    t.join()

print 'End of program'
			

• daemon threads are terminated when the main program exits
• non-daemon threads are terminated only when they finish their tasks

#!/usr/bin/python

import threading
import logging

def daemon():
    logging.debug('Daemon thead starts ...');
    logging.debug('Daemon thead ends ...');

def nonDaemon():
    logging.debug('None-daemon thead starts ...');
    logging.debug('None-daemon thead ends ...');

logging.basicConfig(format='[%(levelname)s] (%(threadName)-10s): %(message)s', level=logging.DEBUG);

d = threading.Thread(target=daemon);
d.setDaemon(True)
nd = threading.Thread(target=nonDaemon);

d.start();
nd.start();

#d.join();
#nd.join();

print 'End of program'
			

#!/usr/bin/python

import threading
import logging
import time

def worker(i):
    """thread worker function"""
    print 'Hello World!', i
    time.sleep(1);

logging.basicConfig(level=logging.DEBUG)
threads = []

#Create threads
for i in range(5):
    threads.append(threading.Thread(target=worker, args = (i, )));

#Start theads
for t in threads:
    t.start()

#Enumerate threads
for t in threading.enumerate():
    logging.debug('Name: %s ...', t.getName());

#Join theads
for t in threads:
    print 'Join', t.ident, t.getName()
    t.join()

print 'End of program'
			

#!/usr/bin/python

import threading
import logging

def worker():
    """thread worker function"""
    logging.debug('Hello World! %s', threading.currentThread().getName())

logging.basicConfig(level=logging.DEBUG)
threads = []

#Create threads
t_1 = threading.Timer(1, worker);
t_2 = threading.Timer(1, worker);

t_1.start();
t_2.start();

#Join theads
for t in threading.enumerate():
    if t is threading.currentThread():
        continue
    logging.debug('Join %d %s', t.ident, t.getName())
    t.join()

print 'End of program'
			

• isSet()
• set()
• clear()
• wait()

#!/usr/bin/python

import threading
import logging

def event_1(e):
    logging.debug('Waiting for the event happens ...');
    e.wait();
    logging.debug('Hello World!');

def event_2(e):
    logging.debug('Start the event ...');
    e.set();

logging.basicConfig(level=logging.DEBUG);

e = threading.Event();

t_1 = threading.Thread(target=event_1, args=(e, ));
t_2 = threading.Thread(target=event_2, args=(e, ));

t_1.start();
t_2.start();
			

• acquire(), request lock, if not available, block the current thread until the lock is available
• acquire(0), request lock, if not available, do not block
• release(), release lock
• Python’s built-in data structures, such as lists, dictionaries, etc., are thread-safe
• Other data structures implemented in Python, such as integers and floats, don’t have that protection

#!/usr/bin/python

import threading
import logging

num = 0;

lock = threading.Lock();

def increase(lock):
    lock.acquire()
    logging.debug('Call increase() in %s ...', threading.currentThread().getName());
    global num;
    num += 1;
    logging.debug('End up thread %s ...', threading.currentThread().getName());
    lock.release()

logging.basicConfig(level=logging.DEBUG);

threads = []

for i in xrange(5):
    threads.append(threading.Thread(target=increase, args=(lock, )));

for t in threads:
    t.start();

for t in threads:
    t.join();

print num
			

• A reentrant lock is a synchronization primitive that may be acquired multiple times by the same thread

import threading

lock = threading.RLock()

print 'First try :', lock.acquire()
print 'Second try:', lock.acquire()
			

#!/usr/bin/python

import threading
import logging

num = 0;

lock = threading.Lock();

def increase(lock):
    with lock:
        logging.debug('Call increase() in %s ...', threading.currentThread().getName());
        global num;
        num += 1;
        logging.debug('End up thread %s ...', threading.currentThread().getName());

logging.basicConfig(level=logging.DEBUG);

threads = []

for i in xrange(5):
    threads.append(threading.Thread(target=increase, args=(lock, )));

for t in threads:
    t.start();

for t in threads:
    t.join();

print num
			

import logging
import threading
import time

logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s (%(threadName)-2s) %(message)s',
                    )

def consumer(cond, l):
    logging.debug('Starting consumer thread %s', threading.currentThread().getName())
    t = threading.currentThread()
    with cond:
        cond.wait()
        logging.debug('Resource is available to consumer')
        print l
        l[0] = 0;

def producer(cond, l):
    """set up the resource to be used by the consumer"""
    logging.debug('Starting producer thread')
    with cond:
        l[0] = 100;
        logging.debug('Making resource available')
        cond.notifyAll()

condition = threading.Condition()
l = range(10);
c1 = threading.Thread(name='c1', target=consumer, args=(condition, l))
c2 = threading.Thread(name='c2', target=consumer, args=(condition, l))
p = threading.Thread(name='p', target=producer, args=(condition, l))

c1.start()
c2.start()
time.sleep(2)
p.start()
			

• Limist the number of threads that are able to access the shared resource at the same time

import logging
import random
import threading
import time

logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s (%(threadName)-2s) %(message)s',
                    )

def worker(s):
    with s:
        logging.debug('Thread: %s ...', threading.currentThread().getName());
        time.sleep(1)

s = threading.Semaphore(2)
for i in range(4):
    t = threading.Thread(target=worker, name=str(i), args=(s, ))
    t.start()
			

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• Documentation