Struggling with Bokeh and Flask to graph data from streaming.
Data source update is scheduled and not managed by Bokeh (I see it is done every second).
How to force a refresh of the graph (possibly not of all the page as there are multiple graphs around in the final version)?
Here is a stripped down and runnable version of the faulty code. Any idea is welcome.
# -*- coding: utf-8 -*-
import numpy as np
import pandas as pd
from bokeh.embed import components
from bokeh.plotting import figure
from bokeh.resources import INLINE
from bokeh.models.sources import ColumnDataSource
from flask import Flask, render_template_string
from flask_apscheduler import APScheduler
from apscheduler.triggers.interval import IntervalTrigger
html_template = """
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
{{ js_resources | safe }}
{{ css_resources | safe }}
</head>
<body>
<div>
{{ plot_div.graph_1 | safe }}
</div>
{{ plot_script | safe }}
</body>
</html>
"""
resources = INLINE
js_resources = resources.render_js()
css_resources = resources.render_css()
app = Flask(__name__)
@app.route("/")
def main_graph():
script, div = components({'graph_1': graph_1.figure,})
return render_template_string(html_template,
js_resources=js_resources,
css_resources=css_resources,
plot_script=script,
plot_div=div)
# -------------------------------------------------------------------------------------------------------------------
class Generic3Lines:
def __init__(self, scheduler):
self.data_source = ColumnDataSource()
self.figure = figure()
self.figure.axis.visible = True
self.update_data()
line1 = self.figure.line(y="value_1", line_color="red", x="date_time", source=self.data_source)
line2 = self.figure.line(y="value_2", line_color="blue", x="date_time", source=self.data_source)
line3 = self.figure.line(y="value_3", line_color="green", x="date_time", source=self.data_source)
scheduler.add_job(id="scheduled_update", func=self.update_data, trigger=IntervalTrigger(seconds=1))
def update_data(self):
df = pd.DataFrame(dict(
date_time = range(180),
"value_1" = np.random.random(size=180)*5+5,
"value_2" = np.random.random(size=180)*5+10,
"value_3" = np.random.random(size=180)*5+15,
))
print(df.head(1))
self.data_source = dict(date_time=df["date_time"],
value_1=df["value_1"],
value_2=df["value_2"],
value_3=df["value_3"],
)
scheduler = APScheduler()
scheduler.start()
graph_1 = Generic3Lines(scheduler=scheduler)
if __name__ == "__main__":
app.run(host="0.0.0.0", port=5050)