是否可以在没有服务器回调的情况下更新散景图? [英] Can I update a bokeh plot without callbacks from the server?

问题描述

我希望当在python中运行的单独算法的结果返回结果时，Bokeh定期且任意地更新，而不是基于Bokeh接口的任何输入.

I want Bokeh to update periodically and arbitrarily when the results from a separate algorithm running in python returns results, not based on any input from the Bokeh interface.

我尝试了各种解决方案，但是它们都依赖于某些UI事件的回调或定期回调，如下面的代码所示.

I've tried various solutions but they all depend on a callback to a some UI event or a periodic callback as in the code below.

import numpy as np
from bokeh.plotting import figure, curdoc
from bokeh.models import ColumnDataSource, Plot, LinearAxis, Grid
from bokeh.models.glyphs import MultiLine
from time import sleep
from random import randint


def getData():  # simulate data acquisition
    # run slow algorith
    sleep(randint(2,7)) #simulate slowness of algorithm
    return dict(xs=np.random.rand(50, 2).tolist(), ys=np.random.rand(50, 2).tolist())


# init plot
source = ColumnDataSource(data=getData())

plot = Plot(
    title=None, plot_width=600, plot_height=600,
    min_border=0, toolbar_location=None)

glyph = MultiLine(xs="xs", ys="ys", line_color="#8073ac", line_width=0.1)
plot.add_glyph(source, glyph)

xaxis = LinearAxis()
plot.add_layout(xaxis, 'below')

yaxis = LinearAxis()
plot.add_layout(yaxis, 'left')

plot.add_layout(Grid(dimension=0, ticker=xaxis.ticker))
plot.add_layout(Grid(dimension=1, ticker=yaxis.ticker))
curdoc().add_root(plot)


# update plot
def update():
    bokeh_source = getData()
    source.stream(bokeh_source, rollover=50)

curdoc().add_periodic_callback(update, 100)

这似乎可行，但这是处理事情的最佳方法吗?除了让Bokeh尝试每100毫秒进行更新之外，我还可以在数据可用时将新数据推送到其中吗?

This does seem to work, but is this the best way to go about things? Rather than having Bokeh try to update every 100 milliseconds can I just push new data to it when it becomes available?

谢谢

推荐答案

您可以使用zmq和asyncio来做到这一点.这是bokeh服务器的代码，它在异步协程中等待数据:

You can use zmq and asyncio to do it. Here is the code for the bokeh server, it wait data in an async coroutine:

from bokeh.models import ColumnDataSource
from bokeh.plotting import figure, curdoc
from functools import partial
from tornado.ioloop import IOLoop
import zmq.asyncio

doc = curdoc()

context = zmq.asyncio.Context.instance()
socket = context.socket(zmq.SUB)
socket.connect("tcp://127.0.0.1:1234")
socket.setsockopt(zmq.SUBSCRIBE, b"")

def update(new_data):
    source.stream(new_data, rollover=50)

async def loop():
    while True:
        new_data = await socket.recv_pyobj()
        doc.add_next_tick_callback(partial(update, new_data))

source = ColumnDataSource(data=dict(x=[0], y=[0]))

plot = figure(height=300)
plot.line(x='x', y='y', source=source)

doc.add_root(plot)
IOLoop.current().spawn_callback(loop)

要发送数据，只需在另一个python进程中运行以下代码即可:

to send the data just run following code in another python process:

import time
import random
import zmq

context = zmq.Context.instance()
pub_socket = context.socket(zmq.PUB)
pub_socket.bind("tcp://127.0.0.1:1234")

t = 0
y = 0

while True:
    time.sleep(1.0)
    t += 1
    y += random.normalvariate(0, 1)
    pub_socket.send_pyobj(dict(x=[t], y=[y]))

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