Running D-tale in Jupyter notebook

Version:

This behaviour is present in all versions of Domino 

Issue:  

When running Dtale in a Jupyter Notebook workspace there is no visualisation presented. You can be seeing either
an empty response or "server IP address could not be found" message. 
Example: 

Cause:

This is caused due to the fact that Dtale is running it's own webserver and is using the run ID as a hostname and address to listen on.  Since Jupyter is running inside a workspace that address will not be reachable. 

Resolution:

The resolution is to use the "app_route" parameter. 

Source code: https://dtale.readthedocs.io/en/latest/_modules/dtale/app.html

:param app_root: Optional path to prepend to the routes of D-Tale. 
:This is used when making use of Jupyterhub server proxy :type app_root: str, optional

Example:

import dtale
import dtale.app as dtale_app
import pandas as pd

df = pd.DataFrame([dict(a=1, b=2), dict(a=2, b=3), dict(a=3, b=4)]).set_index('a')
dtale_app.JUPYTER_SERVER_PROXY = True
d = dtale.show(df, app_root='/domino-g/new-test-15/notebookSession/63242d8719b513588182def4/proxy/')
d

In this case we are setting dtale_app.JUPYTER_SERVER_PROXY to True and also providing the app_root as /<USER>/<PROJECT_NAME>/notebookSession/<SESSION_ID>/proxy . 
The session ID for your workspace can be found in the URL of the workspace as "runid="

Result: