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Dash Long Callbacks Not Working
Added on February 11, 2025 5:08PM
Likes: 0
Replies: 2
kev
Registered Posts: 2 ✭
Hi all,
I'm struggling to get long callbacks to work in Dataiku. When I initalize the app = dash.Dash() instance, the application does not run at all. When I remove it, the application runs but the callback does not work at all. Currently, it only works with a regular callback but I need it to work with a long callback. Thanks in advance!
Best,
import time
import dash
from dash import html, Input, Output, callback
from dash.long_callback import DiskcacheLongCallbackManager
# import dataiku
## Diskcache
import diskcache
import logging
### python-lib function
from long_callback_function import long_callback_function
# logger = logging.getLogger(__name__)
cache = diskcache.Cache("./cache")
long_callback_manager = DiskcacheLongCallbackManager(cache) app = dash.Dash(__name__, long_callback_manager=long_callback_manager)
app.layout = html.Div(
[
html.Div([html.P(id="paragraph_id", children=["Button not clicked"])]),
html.Button(id="button_id", children="Run Job!"),
html.Button(id="cancel_button_id",children="Cancel Running Job")
]
)
@app.long_callback(
Output("paragraph_id", "children"),
Input("button_id", "n_clicks"),
manager=long_callback_manager,
running = [
(Output("button_id","disabled"),True,False),
(Output("cancel_button_id","disabled"),False,True),
],
cancel=[Input("cancel_button_id","n_clicks")],
)
def long_callback(n_clicks):
return long_callback_function(n_clicks) ######################### Long callback function import time
def long_callback_function(n_clicks):
time.sleep(10)
return [f"Clicked {n_clicks} times PLEASE"]
Comments
-
Sarina Dataiker, Dataiku DSS Core Designer, Dataiku DSS Adv Designer, Registered Posts: 319 DataikerHi @kev,
Thank you for your question about using long callbacks within a dash app! You'll want to use the following structure utilizing project libraries to define your long callbacks.
So in your webapp, you'll define your diskcache like so:import diskcache
cache = diskcache.Cache(".")
long_callback_manager = DiskcacheLongCallbackManager(cache)Now, in your project library you'll define your callback code instead of in your webapp code (as Python self-inspection capabilities require the code to be in a full-fledged file) like so:
Then, in your webapp you can call the project library callback code. Here's a full example.
[webapp code]
import time
import dash
from dash import html, Input, Output
from dash.long_callback import DiskcacheLongCallbackManager
from my_dash.callbacks import define_callbackimport diskcache
cache = diskcache.Cache(".")
long_callback_manager = DiskcacheLongCallbackManager(cache)app.layout = html.Div(
[
html.Div([html.P(id="paragraph_id", children=["Button not clicked"])]),
html.Button(id="button_id", children="Run Job!"),
]
)define_callback(app, long_callback_manager)
Project library code stored in a folder namedmy_dashand a file named callbacks.py [project library (lib > python > my_dash > callbacks.py)]
import time
import dash
from dash import Input, Outputdef define_callback(app, long_callback_manager):
@app.long_callback(
output=Output("paragraph_id", "children"),
inputs=Input("button_id", "n_clicks"),
manager=long_callback_manager,
)
def callback(n_clicks):
time.sleep(20)
return [f"Clicked {n_clicks} times"]
I hope that's helpful!
Thank you,
Sarina -
It works, thank you Sarina!
