Example 3 - Caching and Signalling from Sharing Data Between Callbacks page does not work as written

Dash Python
1

I’m trying to run example 3 exactly as posted here: Part 5. Sharing Data Between Callbacks | Dash for Python Documentation | Plotly except for changing from redis to filesystem:

CACHE_CONFIG = {
‘CACHE_TYPE’: ‘filesystem’,
‘CACHE_DIR’: os.getcwd()
}

When run from the terminal in IntelliJ IDEA I get the following error:

Exception in thread Thread-2:
Traceback (most recent call last):
File “/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/threading.py”, line 932, in _bootstrap_inner
self.run()
File “/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/threading.py”, line 870, in run
self._target(*self._args, **self._kwargs)
File “/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/werkzeug/serving.py”, line 996, in inner
srv = make_server(
File “/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/werkzeug/serving.py”, line 845, in make_server
raise ValueError(“cannot have a multithreaded and multi process server.”)
t

Removing ‘processes=6’ from: app.run_server(debug=True, processes=6) fixes the issue. Is the only way to simulate parallel callbacks to run on a WSGI? Or has parallel behavior become a default setting in dash? Thanks for your help.

2

same problem, have you fixed it?