I am having two issues with the @app.long_callback feature.
-
Locally everything is working I make use of the diskcache long call back manager and my long callbacks and normal callbacks work completely fine. However a normal callback that only originally took a couple of seconds to get the response now can take up to two minutes when I have replaced @app.callback for @app.long_callback, the app seems to keep calling the URL many times, eventually the data comes but not as fast as before.
-
Once I uploaded to the server my celery worker is ok/redis setup ok everything is ok, however when I click a button to get my results I get thrown a 502 error like so:
Callback error updating ..accordion-summary.children...analyze-output.data...analyze-output-download.data...graph-components.data..._long_callback_interval_1.disabled...analysis-button.disabled...cancel-button.disabled..._long_callback_store_1.data.
But if I change it back to a @app.callback and the redeploy it works completely fine. Once deployed with @app.long_callback I also still see the issue of it taking a long time for callbacks that should only take a few seconds (I thought redis would have sorted the issue out). There seems to be some sort of issue with @app.long_callback.
My code is set up like so:
app.py imports results.py and other content
# Callback Manager
if os.getenv("IS_SERVER"):
# Create celery object
celery_app = Celery(
__name__,
backend=BE_URL,
broker=BR_URL,
)
# Cache expires weekly - can increase or decrease this amount.
long_callback_manager = CeleryLongCallbackManager(celery_app, cache_by=[lambda: launch_uid], expire=604800)
else:
# For use locally in Windows environment
disk_cache = diskcache.Cache("./cache")
long_callback_manager = DiskcacheLongCallbackManager(disk_cache, cache_by=[lambda: launch_uid], expire=604800)
celery_app = None
inner_layout = html.Div(
[
html.Div(id="hidden-div", style={"display": "none"}),
html.H1("Define path", className="text-center my-5"),
select_nodes,
results,
footer,
],
style={"padding": 20},
)
app.layout = html.Div(children=[header, inner_layout])
app.validation_layout = html.Div([
header,
inner_layout
])
app.run_server(debug=False)
results.py
results = html.Div(
[
dbc.Row(
[
html.Div(
[
dcc.Loading(
[
dbc.Button(
"Analyze",
color="primary",
id="analysis-button",
style={"backgroundColor": colors["green1"], 'margin-right': "100px"},
),
dbc.Button(
"Cancel",
color="primary",
id="cancel-button",
style={"backgroundColor": colors["red1"]},
),
], color=colors["green2"]
)
]),
dcc.Store(id="analyze-output", storage_type="session"),
dcc.Store(id="analyze-output-download", storage_type="session"),
dcc.Store(id="graph-components", storage_type="session"),
],
class_name="text-center",
),
html.Hr(),
dbc.Fade(
[
accordion,
],
appear=False,
id="div-body",
is_in=False,
),
]
)
@app.long_callback(
Output("accordion-summary", "children"),
Output("analyze-output", "data"),
Output("analyze-output-download", "data"),
Output("graph-components", "data"),
Input("analysis-button", "n_clicks"),
State("select-PBG-start", "value"),
State("select-BP-start", "value"),
State("select-COCD-start", "value"),
State("select-PBG-end", "value"),
State("select-BP-end", "value"),
State("select-COCD-end", "value"),
running=[
(Output("analysis-button", "disabled"), True, False),
(Output("cancel-button", "disabled"), False, True),
],
cancel=[Input("cancel-button", "n_clicks")],
prevent_initial_call=True,
)
def update_output_data(
n_clicks: bool,
pbg_start: str,
bp_start: str,
cocd_start: str,
pbg_end: str,
bp_end: str,
cocd_end: str,
):
# my code to query db here
