Can't get Bokeh server running with DirectoryHandler - python-3.x

Question

I'm trying to get a bokeh server running with a DirectoryHandler.
The server seems to start but when I load the page in my browser it shows a blank page.
When I use a ScriptHandler and call the main.py directly everything works fine. The problem is that in this case the static directory is not recognized.
This does not work (DirectoryHandler):
from bokeh.application import Application
from bokeh.application.handlers import DirectoryHandler
from bokeh.server.server import Server
from tornado.ioloop import IOLoop
io_loop = IOLoop.current()
def create_bokeh_server(io_loop, file, port):
"""Start bokeh server with applications paths"""
bokeh_app = Application(DirectoryHandler(filename=file))
# kwargs lifted from bokeh serve call to Server, with created io_loop
kwargs = {
'io_loop': io_loop,
'port': port,
}
server = Server(bokeh_app,**kwargs)
return server
if __name__ == '__main__':
# create server
print('Create server')
bokeh_server = create_bokeh_server(io_loop=io_loop, file='C:/bokeh_app_dir/', port=8080)
# start bokeh server
print('Start bokeh server')
bokeh_server.start()
# start web server
print('Start Localhost')
io_loop.start()
This does work(ScriptHandler)
from bokeh.application import Application
from bokeh.application.handlers.script import ScriptHandler
from bokeh.server.server import Server
from tornado.ioloop import IOLoop
io_loop = IOLoop.current()
def create_bokeh_server(io_loop, file, port):
"""Start bokeh server with applications paths"""
bokeh_app = Application(ScriptHandler(filename=file))
# kwargs lifted from bokeh serve call to Server, with created io_loop
kwargs = {
'io_loop': io_loop,
'port': port,
}
server = Server(bokeh_app,**kwargs)
return server
if __name__ == '__main__':
# create server
print('Create server')
bokeh_server = create_bokeh_server(io_loop=io_loop, file='C:/bokeh_app_dir/main.py', port=8080)
# start bokeh server
print('Start bokeh server')
bokeh_server.start()
# start web server
print('Start Localhost')
io_loop.start()
where main.py is:
rom random import random
from bokeh.layouts import column
from bokeh.models import Button
from bokeh.models.widgets import CheckboxGroup, RadioGroup
from bokeh.palettes import RdYlBu3
from bokeh.plotting import figure, curdoc
# create a plot and style its properties
p = figure(x_range=(0, 100), y_range=(0, 100), toolbar_location=None)
p.border_fill_color = 'black'
p.background_fill_color = 'black'
p.outline_line_color = None
p.grid.grid_line_color = None
# add a text renderer to our plot (no data yet)
r = p.text(x=[], y=[], text=[], text_color=[], text_font_size="20pt",
text_baseline="middle", text_align="center")
i = 0
ds = r.data_source
# create a callback that will add a number in a random location
def callback():
global i
# BEST PRACTICE --- update .data in one step with a new dict
new_data = dict()
new_data['x'] = ds.data['x'] + [random()*70 + 15]
new_data['y'] = ds.data['y'] + [random()*70 + 15]
new_data['text_color'] = ds.data['text_color'] + [RdYlBu3[i%3]]
new_data['text'] = ds.data['text'] + [str(i)]
ds.data = new_data
i = i + 1
def update():
"""Example of updating plot on radio button change"""
if radio_group.active == 0:
p.border_fill_color = 'black'
p.background_fill_color = 'black'
elif radio_group.active == 1:
p.border_fill_color = 'white'
p.background_fill_color = 'white'
else:
p.border_fill_color = 'blue'
p.background_fill_color = 'blue'
# add a button widget and configure with the call back
button = Button(label="Press Me")
button.on_click(callback)
# add group of radio butt
radio_group = RadioGroup(
labels=['black', 'white', 'blue'],
active=0
)
radio_group.on_change('active', lambda attr, old, new: update())
# put the button and plot in a layout and add to the document
curdoc().add_root(column(radio_group, button, p))
What am I missing here?
I need the static directory for images I want to load.

Answer 1

Good working example! I am struggling to recreate though. I ran your code exactly on Windows, Python3.7 and bokeh 1.3.1 and bokeh server launches the app on http://localhost:8080/.
Some things to try:
Where and how are you executing the calling script (the scripts where the only difference is DirectoryHandler or ScriptHandler)? I put mine in a separate run.py and just ran it with "python run.py". run.py can but doesn't have to be in the top level app folder. It runs with main.py as the only file in my top level app folder.
What are outputs of python console logging?
What are outputs of your browsers developer tab (usually F12)? I do get an error that Tornado can't find the favicon.ico file (lil browser thumbnail image)
If you take a look at the Bokeh library code for the DirectoryHandler it doesn't do much beyond decorating the ScriptHandler!
https://docs.bokeh.org/en/latest/_modules/bokeh/application/handlers/directory.html#DirectoryHandler