Python 异步函数调用
我想学习如何在Python3中异步调用函数。我想我能做到。当前,我的代码在命令行上不返回任何内容:Python 异步函数调用,python,tornado,Python,Tornado,我想学习如何在Python3中异步调用函数。我想我能做到。当前,我的代码在命令行上不返回任何内容: #!/usr/bin/env python3 # -*- coding: utf-8 -*- async def count(end): """Print message when start equals end.""" start = 0 while True: if start == end: print('start = {
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
async def count(end):
"""Print message when start equals end."""
start = 0
while True:
if start == end:
print('start = {0}, end = {1}'.format(start, end))
break
start = start + 1
def main():
# Start counting.
yield count(1000000000)
# This should print while count is running.
print('Count is running. Async!')
if __name__ == '__main__':
main()
感谢调用异步函数,您需要提供一个事件循环来处理它。如果您有Tornado应用程序,它会提供这样一个循环,允许您使处理程序异步:
from tornado.web import RequestHandler, url
from tornado.httpserver import HTTPServer
from tornado.ioloop import IOLoop
async def do_something_asynchronous():
# e.g. call another service, read from database etc
return {'something': 'something'}
class YourAsyncHandler(RequestHandler):
async def get(self):
payload = await do_something_asynchronous()
self.write(payload)
application = web.Application([
url(r'/your_url', YourAsyncHandler, name='your_url')
])
http_server = HTTPServer(application)
http_server.listen(8000, address='0.0.0.0')
IOLoop.instance().start()
在Tornado应用程序之外,您可以从任意数量的提供者(包括内置库)获取事件循环:
import asyncio
event_loop = asyncio.get_event_loop()
try:
event_loop.run_until_complete(do_something_asynchronous())
finally:
event_loop.close()