How to design a complex Bokeh Application?

Question

I am programming a bokeh application. I want to split the functionalities into different files. But I want to have some attributes accesible from every class, these attributes should be shared and always updated. For example an attribute which stores a dataframe that all the plots are going to use. So I think I have at least two possible solutions:

Use a big class and include the attributes and methods of other files:

class Bigclass(object):

    from bk_plots import p1, p2, p3
    from bk_data import d1, d2, d3
    from bk_layout import ly1, ly2
    from bk_events import ev1, ev2
    # unfortunately, "from classdefn import *" is an error or warning

    num = 42   # add more members here if you like

Note: this solution was copied from here (partial classes)

Or I could use inheritance. The parent will have the shared attributes. The perk of this system is that I would need to send the rest of the object references to every subclass

class Parent():
    shared = 'parent'

class Plot(Parent):
    def __init__(self):
        Parent.shared = 'plots'   # update class variable from this class
                                # I would need to have references to the objects of other classes

class Data(Parent):
    def __init__(self):
        Parent.shared = 'second'

# [...]

Is there a better way to do this? Which option will bring me less problems?

Asked By: ChesuCR

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Answer 1

Finally I have created an my_bokeh_app folder. There I have an __init__.py file with this content for the initialization:

from my_bokeh_app.bokeh_data import BokehData
from my_bokeh_app.bokeh_plots import BokehPlots
from my_bokeh_app.bokeh_table import BokehDataTable
from my_bokeh_app.bokeh_events import BokehEvents
from my_bokeh_app.bokeh_layout import BokehLayout

BokehData()
BokehPlots()
BokehDataTable()
BokehEvents()
BokehLayout()

I have created a Class to share data among all the objects. This is the class:

class BokehSharedData(object):
    # ------------------- CLASS VARIABLES ---------------------- #
    # This variables are shared. So all the children can access them

    data_source = None

    bk_layout = None
    bk_data = None
    bk_plot = None
    bk_table = None
    bk_events = None

In every class I make a reference to the BokehSharedData class. I also inherit from that class to access to the class variables.

from my_bokeh_app.bokeh_shared_data import BokehSharedData

class BokehData(BokehSharedData):
    def __init__(self, **kwargs):
        self.env = BokehSharedData
        self.env.bk_data = self

        # If for example I want to access to the source attribute from the rest of objects
        # I could make this shortcut on the shared class
        self.env.data_source = ColumnDataSource(...)

    def update_data_source(self):

        # [...]

And I could read the shared attributes or execute methods from other object:

from my_bokeh_app.bokeh_shared_data import BokehSharedData

class BokehPlots(BokehSharedData):
    def __init__(self, **kwargs):
        self.env = BokehSharedData
        self.env.bk_plots = self

        # I could use self.env.data_source here or run some method of BokehData class like this

        self.env.bk_data.update_data_source()

The complete app where you can see all the classes working is here

Answered By: ChesuCR

How to design a complex Bokeh Application?

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