所以,似乎解决我的问题的简单方法是使用threading.local
来存储每个线程的“会话”(在下面的模拟中,仅为随机整数)。也许不是最干净的方法,但现在可以用它。这是一个模拟(Python 3.5.1):
import time
import threading
import concurrent.futures
import random
import logging
logging.basicConfig(level=logging.DEBUG, format='(%(threadName)-0s) %(relativeCreated)d - %(message)s')
x = [0.1, 0.1, 0.2, 0.4, 1.0, 0.1, 0.0]
mydata = threading.local()
def do_work(secs):
if 'session' in mydata.__dict__:
logging.debug('re-using session "{}"'.format(mydata.session))
else:
mydata.session = random.randint(0,1000)
logging.debug('created new session: "{}"'.format(mydata.session))
time.sleep(secs)
logging.debug('slept for {} seconds'.format(secs))
return secs
with concurrent.futures.ThreadPoolExecutor(max_workers=3) as executor:
y = executor.map(do_work, x)
print(list(y))
产生以下输出,显示 “sessions” 确实是每个线程本地的并且被重复使用:
(Thread-1) 29 - created new session: "855"
(Thread-2) 29 - created new session: "58"
(Thread-3) 30 - created new session: "210"
(Thread-1) 129 - slept for 0.1 seconds
(Thread-1) 130 - re-using session "855"
(Thread-2) 130 - slept for 0.1 seconds
(Thread-2) 130 - re-using session "58"
(Thread-3) 230 - slept for 0.2 seconds
(Thread-3) 230 - re-using session "210"
(Thread-3) 331 - slept for 0.1 seconds
(Thread-3) 331 - re-using session "210"
(Thread-3) 331 - slept for 0.0 seconds
(Thread-1) 530 - slept for 0.4 seconds
(Thread-2) 1131 - slept for 1.0 seconds
[0.1, 0.1, 0.2, 0.4, 1.0, 0.1, 0.0]
关于日志记录的小提示:为了在IPython笔记本中使用它,需要稍微修改日志设置(因为IPython已经设置了根记录器)。更健壮的日志设置应该是:
IN_IPYNB = 'get_ipython' in vars()
if IN_IPYNB:
logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
for h in logger.handlers:
h.setFormatter(logging.Formatter(
'(%(threadName)-0s) %(relativeCreated)d - %(message)s'))
else:
logging.basicConfig(level=logging.DEBUG, format='(%(threadName)-0s) %(relativeCreated)d - %(message)s')