我想问一下tornado.concurrent.run_on_executor(后面简称
我找到的所有使用
我想使用
这里有一个小应用程序,以演示我的困惑。
run_on_executor
)的工作原理,因为我可能不理解如何运行同步任务以避免阻塞主IOLoop。我找到的所有使用
run_on_executor
的示例都只是使用time
来阻塞循环。使用time
模块时效果很好,但是当我尝试使用run_on_executor
进行一些耗时的计算时,任务会阻塞IOLoop。虽然我可以看到应用程序使用了多个线程,但仍然会阻塞。我想使用
run_on_executor
来哈希密码,使用bcrypt
,但我用这个计算替换了它,以获得一些额外的测试时间。这里有一个小应用程序,以演示我的困惑。
from tornado.options import define, options
import tornado.web
import tornado.httpserver
from tornado import gen
from tornado.concurrent import run_on_executor
import tornado.httpclient
import tornado.escape
import time
import concurrent.futures
import urllib
executor = concurrent.futures.ThreadPoolExecutor(20)
define("port", default=8888, help="run on the given port", type=int)
# Should not be blocking ?
class ExpHandler(tornado.web.RequestHandler):
_thread_pool = executor
@gen.coroutine
def get(self, num):
i = int(num)
result = yield self.exp(2, i)
self.write(str(result))
self.finish()
@run_on_executor(executor="_thread_pool")
def exp(self, x, y):
result = x ** y
return(result)
class NonblockingHandler(tornado.web.RequestHandler):
@gen.coroutine
def get(self):
http_client = tornado.httpclient.AsyncHTTPClient()
try:
response = yield http_client.fetch("http://www.google.com/")
self.write(response.body)
except tornado.httpclient.HTTPError as e:
self.write(("Error: " + str(e)))
finally:
http_client.close()
self.finish()
class SleepHandler(tornado.web.RequestHandler):
_thread_pool = executor
@gen.coroutine
def get(self, sec):
sec = float(sec)
start = time.time()
res = yield self.sleep(sec)
self.write("Sleeped for {} s".format((time.time() - start)))
self.finish()
@run_on_executor(executor="_thread_pool")
def sleep(self, sec):
time.sleep(sec)
return(sec)
class Application(tornado.web.Application):
def __init__(self):
handlers = [
(r'/exp/(?P<num>[^\/]+)?', ExpHandler),
(r'/nonblocking/?', NonblockingHandler),
(r'/sleep/(?P<sec>[^\/]+)?',SleepHandler)
]
settings = dict(
debug=True,
logging="debug"
)
tornado.web.Application.__init__(self, handlers, **settings)
def main():
tornado.options.parse_command_line()
http_server = tornado.httpserver.HTTPServer(Application())
http_server.listen(options.port)
io_loop = tornado.ioloop.IOLoop.instance()
io_loop.start()
if __name__ == "__main__":
main()
如果您能解释为什么在 executor
中运行的 ExpHandler
会阻塞循环,我将非常感激。