问题
Why is Flask hanging after importing the pandas lib or several other scientific libs? It still works, when running it locally via SSH, but when visiting the URL the browser loads and loads and nothing happens.
回答1:
After a long and painful exercise, I was able to finally get my app running .The issue is with the pandas 0.19.2 built when the application is getting imported in the .wsgi file
To resolve it Remove your imports from the global level and insert them at the function level
import pandas as pd
....
@app.route('/getFunction', methods=["GET"])
def sample_get_function():
movieData=pd.read_csv('someData.csv')
to
....
@app.route('/getFunction', methods=["GET"])
def sample_get_function():
import pandas as pd
movieData=pd.read_csv('someData.csv')
This is not a very good solution but it is working
回答2:
The solution is for Ubuntu with Apache2 server. You have to configure the following file:
/etc/apache2/sites-available/your-flask-app-file.conf
paste the following line below WSGIScriptAlias:
WSGIApplicationGroup %{GLOBAL}
回答3:
The other solution by @saitam was necessary, but not sufficient in my case.
As before edit:
/etc/apache2/sites-available/<your-flask-app>.conf
Add or update WSGIApplicationGroup with:
WSGIApplicationGroup %{GLOBAL}
and remove or edit WSGIProcessGroup such that you have:
WSGIProcessGroup %{GLOBAL}
When this was set to something else, the problem persisted.
Some people advocate setting the number of threads to 1, but this was not necessary for me. The following works fine:
WSGIDaemonProcess <...> processes=2 threads=6
Linux version: Ubuntu 14.04.3 LTS
Pandas version: 0.19.2
Python version: 3.4.3
Apache version: 2.4.7
来源：https://stackoverflow.com/questions/41099433/flask-hangs-after-importing-pandas-also-numpy-matplotlib-etc