What is dolo?

Dolo is something I put together over a weekend or two. Its a way to create web-based dashboards by writing a simple python script. The programming model is declarative and very similar to that of React. The API is pretty much a copy of streamlit's, but feature set is smaller and implementation is simpler.

I was blown away by streamlit's design and simplicity (and valuation) when I first used it, so decided to hack together a smaller working copy. Compared to streamlit, dolo only has a handful of components, and is more of a toy rather than a polished, production-ready thing.

How to use

• Call dolo.write to render markup
• dolo.button(...) creates a button and returns the state of the button (True or False)
• dolo.dropdown(...) creates a dropdown and returns the selected option as a string
• dolo.filter(...) creates a filter and returns the active filter as a string
• dolo.plot(...) plots a matplotlib figure
• You can cache the outputs of expensive functions using the dolo.cache decorator
• Put the code in lit.py and use flask run to run the app

How it works

• The output of the script is used to generate the markup
• For every incoming request dolo re-runs the script with the updated component state and re-renders the webpage based on the script's output.
• The state is stored in a python dictionary.
• All rendering is done server-side, which means even a button press refreshes the entire page. This is different from streamlit which is more of an SPA and changes are streamed over a websocket.

Bugs / Possible Bugs

• state dictionary isn't thread-safe
• UI breaks if a state update happens while the page is refreshing
• using matplotlib.plt isn't recommended in a multi-threaded environment