Circular Callbacks in Julia for Dash 1.6?

Dash R, MATLAB, Julia Dash Julia
1

Can you do circular callbacks in Julia Dash?

It seems that this functionality was available in python’s dash 1.19…

But I can’t seem to replicate it in Julia… I do get an error message regarding circular callbacks though.

If its not implemented, any ideas on when it will be?

2

Hey @Wingmore this should work if it works in Python. Can you please post a small Julia code example here that’s not working?

3

Circular callbacks are documented in Advanced Callbacks | Dash for Julia Documentation | Plotly.

4

Code tried:

@time using Dash, DashHtmlComponents, DashCoreComponents, DashTable
@time using DashBootstrapComponents

external_stylesheets = ["https://codepen.io/chriddyp/pen/bWLwgP.css"]

app = dash(external_stylesheets=external_stylesheets)

app.layout = html_div() do
    [
        dcc_slider(
            id="slider-circular", min=0, max=20, 
            marks=[(i=string(i),) for i in 1:21], 
            value=3
        ),
        dcc_input(
            id="input-circular", type="number", min=0, max=20, value=3
        ),
    ]
end

callback!(
    app,
    Output("input-circular", "value"),
    Output("slider-circular", "value"),
    Input("input-circular", "value"),
    Input("slider-circular", "value"),
 ) do input_value, slider_value
    ctx = callback_context()
    trigger_id = ctx.triggered[0]["prop_id"].split(".")[0]
    trigger_id == "input-circular" ? value = input_value : slider_value
    return value, value
end

ERror:

ERROR: LoadError: Circular input and output arguments were found. Please verify that callback outputs are not also input arguments.
Stacktrace:
 [1] error(s::String)
   @ Base .\error.jl:33
 [2] check_callback(func::Function, app::Dash.DashApp, deps::Dash.CallbackDeps)
   @ Dash C:\Users\Wingmore\.julia\packages\Dash\Weukk\src\app\callbacks.jl:181
 [3] _callback!(func::var"#467#468", app::Dash.DashApp, deps::Dash.CallbackDeps; prevent_initial_call::Nothing)
   @ Dash C:\Users\Wingmore\.julia\packages\Dash\Weukk\src\app\callbacks.jl:129
 [4] callback!(::var"#467#468", ::Dash.DashApp, ::Output{String}, ::Vararg{Dash.Dependency, N} where N; prevent_initial_call::Nothing)
   @ Dash C:\Users\Wingmore\.julia\packages\Dash\Weukk\src\app\callbacks.jl:108
 [5] callback!(::var"#467#468", ::Dash.DashApp, ::Output{String}, ::Output{String}, ::Input{String}, ::Input{String})
   @ Dash C:\Users\Wingmore\.julia\packages\Dash\Weukk\src\app\callbacks.jl:104
 [6] top-level scope
   @ c:\Users\Wingmore\Desktop\everything\Julia tutorials\circular_callback_dash.jl:21
in expression starting at c:\Users\Wingmore\Desktop\everything\Julia tutorials\circular_callback_dash.jl:21
5

Your link redirects to the python one. Also I’ve noticed that the julia Advanced callback ends prematurely: theres some sections in python not in julia docu here:

https://dash-julia.plotly.com/advanced-callbacks

6

Hi all!
I added the possibility of circular callbacks in Dash.jl 1.1.0

P.S. Sorry, I should have answered earlier, but I was following julia’s resources and forgot about the fact that the discussion is also going on in the Plotly community

7

Circular callbacks still do not work for me :\

ERROR: LoadError: LoadError: Circular input and output arguments were found. Please verify that callback outputs are not also input arguments.