Notebook as a REST Server with voila possible?

[joshy]

I am using voila for deploying small applications as jupyter notebooks. Some times I don't need a frontend but just some services which can be accessed via http. The nice thing about jupyter and its eco-system is, that I can change the notebook, save it and it is immediately deployed in production with voila. Is there a way to run a jupyter notebook with voila which acts as a REST server? Maybe it is a stupid question but especially for microservices it would be great. Thanks for your time and keep up the great work!

Best regards,
Joshy

[jtpio]

@joshy depending on what you would like to achieve, maybe using ipywidgets in the Voila dashboard would be enough to produce something like a minimal "REST server"?

Technically it would not really be REST, but with ipywidgets you could have your main logic written in Python in the notebook, and react on user input such as clicking on a button or submitting some text.

[joshy]

@jtpio thanks for your answer. Maybe a specific examples makes it clearer what I am searching for. I have a small flask app where users can upload an excel and it searches a database for each row (patientid) some values and gives back an excel. This can be done also with ipywidgets + voila. On the same flask app I also have a http route like .../query?patid= which give back a json for a single case. If this can be somehow done with ipywidgets, I can get rid of the flask app and replace it with a notebook + voila. I have no idea how ipywidgets can 'act' like a REST-like server, if you have any example I am more than happy to try it out.

[jtpio]

Sure, there are a couple of examples on the Voila Gallery: https://voila-gallery.org/

It wouldn't be a real REST-like application. It's more that performing actions with widgets in the browser would then trigger some Python callbacks to be executed in the kernel started by Voila to run the notebook.

You should also be able to get the query string parameters following this approach: https://github.com/voila-dashboards/voila/blob/main/notebooks/query-strings.ipynb

[joshy]

I found a solution at least for writing the http handler in a notebook. It is the Jupyter Kernel Gateway with notebook-http mode. It let's me write http handlers in cells and I can run it with jupyter.

# GET /hello/world
print("hello world")

Can I run voila with jupyter_kernel_gateway?