I have written a service that reads from the file system in order to determine state, and holds that state for a while instead of constantly updating the file system. Therefore it's paramount that there is only one instance of that service. Now it seems Web Apps instantiates two instances of a Flask service by default.
Is this a documented thing, or have I understood some configuration wrong? Are they in fact replicas or some other mechanism? And most importantly, how can I disable this feature?
My application factory:
from flask import Flask
def create():
app = Flask(__name__)
d = {'t': 0}
@app.route('/', methods=['GET'])
def main():
d['t'] += 1
return 'Calls: %d' % d['t'], 200
return app
And web.config:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<appSettings>
<add key="PYTHONPATH" value="D:\home\site\wwwroot" />
<add key="WSGI_HANDLER" value="app.create()" />
<add key="WSGI_LOG" value="D:\home\site\wwwroot\wsgi.log" />
</appSettings>
<system.webServer>
<handlers>
<add name="PythonHandler" path="*" verb="*" modules="FastCgiModule"
scriptProcessor="D:\home\python364x64\python.exe|D:\home\python364x64\wfastcgi.py"
resourceType="Unspecified" requireAccess="Script"/>
</handlers>
</system.webServer>
</configuration>
After startup, these calls return a sequence like 1, 1, 2, 2, 3, 3... which to me indicates that there are two instances running and a balancer round-robining the two. The pattern seems to be fairly regular, not skipping the other service for example.
