我想使用ipdb（或其他python调试器）来调试使用Flask和Dash的应用程序。当我想使用函数将数据传递给Dash时，会出现问题（as mentioned here是一种在页面重新加载时提供更新的方法）。在多线程方面，Ipdb似乎有一些问题。有代码：
#!/usr/bin/env python
import json
import requests
from flask import Flask
from flask.globals import g
import dash
import dash_core_components as dcc
import dash_html_components as html
app = Flask(__name__)
dash_app = dash.Dash(server=app, url_base_pathname='/analytics/')
def get_analytics_data():
return json.loads(
requests.get('http://localhost:8000/api/').text
)
def graphs():
return (
dcc.Graph(
id='orders',
figure={
'data': [
{
'x': [key for key in get_analytics_data().keys()],
'y': [value for _, value in get_analytics_data().items()],
'name': 'restaurants',
'type': 'bar'
}
]
}
),
)
def serve_layout():
import ipdb; ipdb.set_trace()
return html.Div(children=[
html.H1(children='Hello, dash'),
*graphs()
])
dash_app.layout = serve_layout
if __name__ == '__main__':
app.run(debug=True)
注意：我希望保留此app = Flask(__name__)以便进一步开发。
有堆栈跟踪： 。当我在页面上重新加载时会发生这种情况：
* Debugger is active!
* Debugger PIN: 224-366-292
127.0.0.1 - - [07/Jun/2018 12:32:53] "GET /analytics/ HTTP/1.1" 200 -
127.0.0.1 - - [07/Jun/2018 12:32:54] "GET /analytics/_dash-layout HTTP/1.1" 500 -
Traceback (most recent call last):
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/app.py", line 2309, in __call__
return self.wsgi_app(environ, start_response)
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
response = self.full_dispatch_request()
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/app.py", line 1741, in handle_exception
reraise(exc_type, exc_value, tb)
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
raise value
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
response = self.full_dispatch_request()
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
rv = self.dispatch_request()
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
raise value
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
rv = self.dispatch_request()
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/dash/dash.py", line 160, in serve_layout
layout = self._layout_value()
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/dash/dash.py", line 131, in _layout_value
self._cached_layout = self._layout()
File "/home/gonczor/Projects/analytics/analytics/main.py", line 53, in serve_layout
return html.Div(children=[
File "/home/gonczor/Projects/analytics/analytics/main.py", line 53, in serve_layout
return html.Div(children=[
File "/usr/lib/python3.6/bdb.py", line 48, in trace_dispatch
return self.dispatch_line(frame)
File "/usr/lib/python3.6/bdb.py", line 66, in dispatch_line
self.user_line(frame)
File "/usr/lib/python3.6/pdb.py", line 261, in user_line
self.interaction(frame, None)
File "/home/gonczor/Projects/analytics/venv-analytics/lib/python3.6/site-packages/IPython/core/debugger.py", line 297, in interaction
OldPdb.interaction(self, frame, traceback)
File "/usr/lib/python3.6/pdb.py", line 344, in interaction
signal.signal(signal.SIGINT, Pdb._previous_sigint_handler)
File "/usr/lib/python3.6/signal.py", line 47, in signal
handler = _signal.signal(_enum_to_int(signalnum), _enum_to_int(handler))
ValueError: signal only works in main thread
我可以使用PyCharm的调试器成功调试应用程序，但它并不总是可用，所以我想要一些通用的控制台运行调试器。
修改
我已经完成了服务器创建过程，发现Falsk默认使用单线程服务器（并且单处理也是如此）。这在我的虚拟环境中run_simple()的{{1}}中进行处理。