线程 'Thread-1' 中没有当前事件循环

Question

我对python非常熟悉，我正在尝试实现一个API，用于从Interactive Brokers Trader Workstation请求一些数据。我正在使用Flask和ib_insync。

这是我的代码：

import configparser
import json
import logging.config
from flask import Flask
from ib_insync import IB
flask = Flask(__name__)
ib = IB()
config = configparser.ConfigParser()
config.read('settings.ini')
logging.config.fileConfig('logging.conf')
logger = logging.getLogger('ib-custom')

@flask.route('/health', methods=['GET'])
def health():
return 'OK'

@flask.route('/summary', methods=['GET'])
def account_summary():
logger.debug('account_summary called')
summary = ib.accountSummary()
return json.dumps([ob._asdict() for ob in summary])

if __name__ == '__main__':
ib.connect('127.0.0.1', 7497, clientId=1)
logger.info('Application started')
flask.run(debug=True, use_reloader=False)

当我尝试执行localhost:5000/summary时，它会引发错误。这是堆叠竞赛：

Traceback (most recent call last):
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/app.py", line 2464, in __call__
return self.wsgi_app(environ, start_response)
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/app.py", line 2450, in wsgi_app
response = self.handle_exception(e)
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/app.py", line 1867, in handle_exception
reraise(exc_type, exc_value, tb)
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
raise value
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app
response = self.full_dispatch_request()
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/app.py", line 1821, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
raise value
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request
rv = self.dispatch_request()
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/main.py", line 27, in account_summary
summary = ib.accountSummary()
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/ib_insync/ib.py", line 405, in accountSummary
return self._run(self.accountSummaryAsync(account))
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/ib_insync/ib.py", line 310, in _run
return util.run(*awaitables, timeout=self.RequestTimeout)
File "/Users/irusanov/Projects/PycharmProjects/ib-custom/venv/lib/python3.8/site-packages/ib_insync/util.py", line 291, in run
loop = asyncio.get_event_loop()
File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/asyncio/events.py", line 639, in get_event_loop
raise RuntimeError('There is no current event loop in thread %r.'
RuntimeError: There is no current event loop in thread 'Thread-1'.

为什么会出现此错误？如何修复？

Answer 1

Flask似乎使用了自己的内部阻塞/回调/线程模型，与该项目所基于的Asyncio不兼容。来源：https://github.com/erdewit/ib_insync/issues/266

可以使用另一个框架而不是Flask来实现所需的行为。例如Quart。

在使用Quart的情况下，可以重写此代码：

import asyncio
import configparser
import json
import logging.config
import nest_asyncio
from quart import Quart
from ib_insync import IB, util
nest_asyncio.apply()
qrt = Quart(__name__)
ib = IB()
config = configparser.ConfigParser()
config.read('settings.ini')
logging.config.fileConfig('logging.conf')
logger = logging.getLogger('ib-custom')

@qrt.route('/health', methods=['GET'])
def health():
return 'OK'

@qrt.route('/summary')
async def summary():
with await IB().connectAsync() as ibi:
acct = ibi.managedAccounts()[0]
summary = ibi.accountSummary(acct)
await ibi.accountSummaryEvent
resp = json.dumps(util.tree(summary))
return resp

@qrt.route('/pnl')
async def pnl():
with await IB().connectAsync() as ibi:
acct = ibi.managedAccounts()[0]
pnl = ibi.reqPnL(acct)
await ibi.pnlEvent
resp = json.dumps(util.tree(pnl))
return resp

if __name__ == '__main__':
# ib.connect('127.0.0.1', 7497, clientId=1)
logger.info('Application started')
qrt.run(debug=True)