ZeroMQ and Dash on linux cause "Address already in use" error\ - julia

Question

Puzzled by this error message as nothing is running on the port for Dash (I run sudo netstat -nlp to make sure) and the ZMQ is working, on it’s own, perfectly as is the Dash functionality. Put them together, which doesn’t seem unreasonable, and they should work well. I don’t see how the bindings are causing the issue.
I’m using linux and I was told that ZMQ and Dash are using the same port. My problem is that I don’t know how to address this issue.
here’s the error
ave#deepthought:~/tontine_2022/just_messing$ julia 6_25_min_dash.jl
starting IN Socket 5555
Received request: END
dying
ERROR: LoadError: TaskFailedException
Stacktrace:
[1] wait
# ./task.jl:334 [inlined]
[2] hot_restart(func::Dash.var"#72#74"{Dash.DashApp, String, Int64}; check_interval::Float64, env_key::String, suppress_warn::Bool)
# Dash ~/.julia/packages/Dash/yscRy/src/utils/hot_restart.jl:23
[3] run_server(app::Dash.DashApp, host::String, port::Int64; debug::Bool, dev_tools_ui::Nothing, dev_tools_props_check::Nothing, dev_tools_serve_dev_bundles::Nothing, dev_tools_hot_reload::Nothing, dev_tools_hot_reload_interval::Nothing, dev_tools_hot_reload_watch_interval::Nothing, dev_tools_hot_reload_max_retry::Nothing, dev_tools_silence_routes_logging::Nothing, dev_tools_prune_errors::Nothing)
# Dash ~/.julia/packages/Dash/yscRy/src/server.jl:64
[4] build_dash()
# Main ~/tontine_2022/just_messing/6_25_min_dash.jl:46
[5] top-level scope
# ~/tontine_2022/just_messing/6_25_min_dash.jl:68
nested task error: LoadError: StateError("Address already in use")
Stacktrace:
[1] bind(socket::Socket, endpoint::String)
# ZMQ ~/.julia/packages/ZMQ/R3wSD/src/socket.jl:58
[2] top-level scope
# ~/tontine_2022/just_messing/6_25_min_dash.jl:10
[3] include(mod::Module, _path::String)
# Base ./Base.jl:418
[4] include(x::String)
# Main.##274 ~/.julia/packages/Dash/yscRy/src/utils/hot_restart.jl:21
[5] top-level scope
# ~/.julia/packages/Dash/yscRy/src/utils/hot_restart.jl:21
[6] eval
# ./boot.jl:373 [inlined]
[7] eval
# ./Base.jl:68 [inlined]
[8] (::Dash.var"#21#22"{String, Symbol})()
# Dash ./task.jl:423
in expression starting at /home/dave/tontine_2022/just_messing/6_25_min_dash.jl:10
in expression starting at /home/dave/tontine_2022/just_messing/6_25_min_dash.jl:68
dave#deepthought:~/tontine_2022/just_messing$
can someone look at my code to see what I am doing wrong please?
here’s the ZMQ pull code
using ZMQ
using Dash
using DataFrames
context = Context()
in_socket = Socket(context, PULL)
ZMQ.bind(in_socket, "tcp://*:5555")
println("starting IN Socket 5555")
dash_columns = ["sym","price","sdmove","hv20","hv10","hv5","iv","iv%ile","prc%ile","volume"]
df_dash_table = DataFrame([col => (col == "sym" ? String : Float64)[] for col in dash_columns ])
function build_dash()
app = dash()
app.layout = html_div() do
html_h1("tontine2"),
dash_datatable( id="table", columns=[Dict("name" =>i, "id" => i) for i in names(df_dash_table)],
data = Dict.(pairs.(eachrow(df_dash_table))),
editable=false,
filter_action="native",
sort_action="native",
sort_mode="multi",
row_selectable="multi",
row_deletable=false,
selected_rows=[],
## page_action="native",
## page_current= 0,
## page_size= 10,
)#end dash_datatable
end
run_server(app, "0.0.0.0", debug=true)
end
while true
message = String(ZMQ.recv(in_socket))
println("Received request: $message")
if message == "END"
println("dying")
break
end
end
build_dash()
and here’s the code to trigger the event
using ZMQ
context = Context()
stk_socket = Socket(context, PUSH)
ZMQ.connect(stk_socket, "tcp://localhost:5555")
ZMQ.send(stk_socket,"END")
ZMQ.close(stk_socket)
ZMQ.close(context)

Answer 1

This works here:
using ZMQ
using Dash
using Distributed
app = dash(external_stylesheets = ["https://codepen.io/chriddyp/pen/bWLwgP.css"])
app.layout = html_div() do
html_h1("Hello Dash"),
html_div("Dash.jl: Julia interface for Dash"),
dcc_graph(
id = "example-graph",
figure = (
data = [
(x = [1, 2, 3], y = [4, 1, 2], type = "bar", name = "SF"),
(x = [1, 2, 3], y = [2, 4, 5], type = "bar", name = "Montréal"),
],
layout = (title = "Dash Data Visualization",)
)
)
end
#spawn run_server(app, "0.0.0.0", 8080)
function testpush()
context = Context()
stk_socket = Socket(context, PUSH)
ZMQ.connect(stk_socket, "tcp://localhost:5555")
ZMQ.send(stk_socket,"END")
ZMQ.close(stk_socket)
ZMQ.close(context)
end
context = Context()
in_socket = Socket(context, PULL)
ZMQ.bind(in_socket, "tcp://*:5555")
sleep(1)
#spawn testpush()
sleep(5)
If you are running the program in an editor task, please note that the spawned process will now continue until you restart the editor. Perhaps a spawned process is clinging to the port?