Exception happened during processing of request

Dash Python
1

Hi all,
I’m new to Dash and Plotly and currently I’m facing this issue.
My goal is to plot live data on the app. I’m using REST based calls to obtain my data.

My app runs for a while and then starts throwing this error:

Exception happened during processing of request from ('127.0.0.1', 6600)
Traceback (most recent call last):
  File "C:\Users\ _________\AppData\Local\Programs\Python\Python37-32\lib\socketserver.py", line 316, in _handle_request_noblock
    self.process_request(request, client_address)
  File "C:\Users\ _________\AppData\Local\Programs\Python\Python37-32\lib\socketserver.py", line 665, in process_request
    t.start()
  File "C:\Users\ _________\AppData\Local\Programs\Python\Python37-32\lib\threading.py", line 852, in start
    _start_new_thread(self._bootstrap, ())
RuntimeError: can't start new thread

Here is my Current Code:

import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output
import plotly
import time
import requests
import warnings
import json
from datetime import datetime
import collections

app = dash.Dash()

#Boostrap CSS.
app.css.append_css({'external_url': 'https://codepen.io/amyoshino/pen/jzXypZ.css'}) 

colors = {
    'background': '#111111',
    'text1': '#7FDBFF',
    'text': '#000000'
}

data={}

G1 = collections.deque(maxlen=10)
G2 = collections.deque(maxlen=10)
G3 = collections.deque(maxlen=10)
G4 = collections.deque(maxlen=10)
T = collections.deque(maxlen=10)

auth1 = ("..............",".......................")
def rValRESTLatest(param, mode, item = 'None'):
    url = "https://" + "11.111.11.111" + ":" + "1111" + "/DataStoreValueLatest/" + param + ':' + item
    warnings.filterwarnings("ignore")
    r1 = requests.get(url, auth = auth1, verify = False)
    for line1 in r1.iter_lines(decode_unicode=True):
      if line1:
        var1 = json.loads(line1)
    a = var1[0]
    if mode == 1:
        b = float(a['value'])
        return(b)
    elif mode == 2:
        b = str(a['value'])
        return(b)
 
def dataManipulation(data):
    for i in range(0,10):
        G1.append(rValRESTLatest('TransVel',1,'R2D2'))
        G2.append(rValRESTLatest('RotVel',1,'R2D2'))
        G3.append(rValRESTLatest('BatteryStateOfCharge',1,'R2D2'))
        G4.append(rValRESTLatest('CPUUse',1,'R2D2'))
        T.append(datetime.now())
        time.sleep(0.5)
    data['g1']=list(G1)
    data['g2']=list(G2)
    data['g3']=list(G3)
    data['g4']=list(G4)
    data['t']=list(T)
    return(data)

app.layout = html.Div(
    html.Div([
        html.H4('Graphing Interface'),
        html.Div(id='live-update-text'),
        dcc.Graph(id='live-update-graph'),
        dcc.Interval(
            id='interval-component',
            interval=10*1000, # in milliseconds
            n_intervals=0
        )
    ])
)

@app.callback(Output('live-update-graph', 'figure'),
              [Input('interval-component', 'n_intervals')])


def update_graph_live(n):
    f_data = dataManipulation(data)
    # Create the graph with subplots
    fig = plotly.tools.make_subplots(rows=4, cols=1, vertical_spacing=0.2)
    fig['layout']['margin'] = {
        'l': 30, 'r': 10, 'b': 30, 't': 10
    }
    fig['layout']['legend'] = {'x': 0, 'y': 1, 'xanchor': 'right'}

    fig.append_trace({
        'x': f_data['t'],
        'y': f_data['g1'],
        'name': 'Graph1',
        'mode': 'lines+markers',
        'type': 'scatter'
    }, 1, 1)
    fig.append_trace({
        'x': f_data['t'],
        'y': f_data['g2'],
        'name': 'Graph2',
        'mode': 'lines+markers',
        'type': 'scatter'
    }, 2, 1)
    fig.append_trace({
        'x': f_data['t'],
        'y': f_data['g3'],
        'name': 'Graph3',
        'mode': 'lines+markers',
        'type': 'scatter'
    }, 3, 1)
    fig.append_trace({
        'x': f_data['t'],
        'y': f_data['g4'],
        'name': 'Graph4',
        'mode': 'lines+markers',
        'type': 'scatter'
    }, 4, 1)

    return fig

`if __name__ == '__main__':`
    app.run_server(debug=True)
  1. I don’t understand why this is happening?
  2. Is there any documentation on dcc.Interval? I do not understand how n_intervals works.

Any help is appreciated. Thank you for the support in advance!