sched — 定时消息调度器

Running Events With a Delay

# sched_basic.py
import sched
import time

scheduler = sched.scheduler(time.time, time.sleep)


def print_event(name, start):
    now = time.time()
    elapsed = int(now - start)
    print('EVENT: {} elapsed={} name={}'.format(
        time.ctime(now), elapsed, name))


start = time.time()
print('START:', time.ctime(start))
scheduler.enter(2, 1, print_event, ('first', start))
scheduler.enter(3, 1, print_event, ('second', start))

scheduler.run()

Overlapping Events

# sched_overlap.py
import sched
import time

scheduler = sched.scheduler(time.time, time.sleep)


def long_event(name):
    print('BEGIN EVENT :', time.ctime(time.time()), name)
    time.sleep(2)
    print('FINISH EVENT:', time.ctime(time.time()), name)


print('START:', time.ctime(time.time()))
scheduler.enter(2, 1, long_event, ('first',))
scheduler.enter(3, 1, long_event, ('second',))

scheduler.run()

Event Priorities

# sched_priority.py
import sched
import time

scheduler = sched.scheduler(time.time, time.sleep)


def print_event(name):
    print('EVENT:', time.ctime(time.time()), name)


now = time.time()
print('START:', time.ctime(now))
scheduler.enterabs(now + 2, 2, print_event, ('first',))
scheduler.enterabs(now + 2, 1, print_event, ('second',))

scheduler.run()

Canceling Events

# sched_cancel.py
import sched
import threading
import time

scheduler = sched.scheduler(time.time, time.sleep)

# Set up a global to be modified by the threads
counter = 0


def increment_counter(name):
    global counter
    print('EVENT:', time.ctime(time.time()), name)
    counter += 1
    print('NOW:', counter)


print('START:', time.ctime(time.time()))
e1 = scheduler.enter(2, 1, increment_counter, ('E1',))
e2 = scheduler.enter(3, 1, increment_counter, ('E2',))

# Start a thread to run the events
t = threading.Thread(target=scheduler.run)
t.start()

# Back in the main thread, cancel the first scheduled event.
scheduler.cancel(e1)

# Wait for the scheduler to finish running in the thread
t.join()

print('FINAL:', counter)