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Show HN: WASM-powered codespaces for Python notebooks on GitHub

Show HN: WASM-powered codespaces for Python notebooks on GitHub

24 comments

·January 14, 2025

Hi HN!

Last year, we shared marimo [1], an open-source reactive notebook for Python with support for execution through WebAssembly [2].

We wanted to share something new: you can now run marimo and Jupyter notebooks directly from GitHub in a Wasm-powered, codespace-like environment. What makes this powerful is that we mount the GitHub repository's contents as a filesystem in the notebook, making it really easy to share notebooks with data.

All you need to do is prepend 'marimo.app' to any Python notebook on GitHub. Some examples:

- Jupyter Notebook: https://marimo.app/github.com/jakevdp/PythonDataScienceHandb...

- marimo notebook: https://marimo.app/github.com/marimo-team/marimo/blob/07e8d1...

Jupyter notebooks are automatically converted into marimo notebooks using basic static analysis and source code transformations. Our conversion logic assumes the notebook was meant to be run top-down, which is usually but not always true [3]. It can convert many notebooks, but there are still some edge cases.

We implemented the filesystem mount using our own FUSE-like adapter that links the GitHub repository’s contents to the Python filesystem, leveraging Emscripten’s filesystem API. The file tree is loaded on startup to avoid waterfall requests when reading many directories deep, but loading the file contents is lazy. For example, when you write Python that looks like

```python

with open("./data/cars.csv") as f: print(f.read())

# or

import pandas as pd pd.read_csv("./data/cars.csv")

```

behind the scenes, you make a request [4] to https://raw.githubusercontent.com/<org>/<repo>/main/data/car....

Docs: https://docs.marimo.io/guides/publishing/playground/#open-no...

[1] https://github.com/marimo-team/marimo

[2] https://news.ycombinator.com/item?id=39552882

[3] https://blog.jetbrains.com/datalore/2020/12/17/we-downloaded...

[4] We technically proxy it through the playground https://marimo.app to fix CORS issues and GitHub rate-limiting.

HanClinto

I absolutely love that this can be hosted on Github Pages. Am I correct in understanding that these notebooks will run independently, and will not need to proxy through marimo.app (in case the app goes down), or is that what the CORS thing is about in note 4, and it will still need to go through this domain?

mscolnick

Yea, this can be hosted on GitHub pages without any vendor infra (no marimo.app)

These are two separate features:

1) marimo.app + github.com/path/to/nb.ipynb does run on marimo.app infra. this is what the Show HN was about

2) separately, you can use the marimo CLI to export assets to deploy to GitHub page: `marimo export html-wasm notebook.py -o output_dir --mode run` which can then can be uploaded to GH pages. This does not find all the data in your repo, so you would need to stick any data you was to access in a /public folder for your site. More docs here: https://docs.marimo.io/guides/exporting/?h=marimo+export+htm...

wolfgangK

Nice ! Is it possible to connect to an in browser DB like WASM DuckDB https://duckdb.org/docs/api/wasm/overview.html or https://github.com/babycommando/entity-db ?

That would be most useful imho !

akshayka

duckdb works — just import duckdb. We also have built-in SQL cells, powered by duckdb, which should also work.

data-ottawa

I love seeing projects like this. When Pyiodide came out I was excited but it was a bit difficult to use, this looks and feels fantastic.

I really like Observable as well, but I've found it difficult to find robust and broad numerical libraries in javascript like what Python has.

I would love for this type of tool to redefine how we do science. It would be amazing if many scientific papers included both their data and the code in an interactive environment with zero installs and configuration. Plus when discussing a paper you could "fork" it and explore different analysis options live which for many fields would be totally feasible to do in the browser.

dmadisetti

I feel like pytomls and shared source are becoming standard, but yes-

notebooks vs research code are sometimes very separate, very difficult to directly reproduce. A big difficultly with "working out of the box, shared in browser" is that weights, training, inference, simulations- are all still very compute intensive.

BUT the nice thing about a stateless notebook, is that you can precompute values- and cache them. I've been really excited about expanding marimo's caching system, and would love to get to a point whether sharing a notebook means being able to run the research yourself without some big setup dance.

hzuo

Super cool to see a real use-case of WASM outside of just game dev and nerding out.

pjmlp

We also have Flash, Java Applets, ActiveX and Silverlight back, running on top of WebAssembly.

PKop

Blazor is another example

dhbradshaw

This is really cool -- going to show it off to my team. I love the fact that you opened it up so that it will work with Jupyter notebooks as well.

lordswork

The future is awesome. Thanks for building this!

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westurner

> CORS and GitHub

The Godot docs mention coi-serviceworker; https://github.com/orgs/community/discussions/13309 :

gzuidhof/coi-serviceworker: https://github.com/gzuidhof/coi-serviceworker :

> Cross-origin isolation (COOP and COEP) through a service worker for situations in which you can't control the headers (e.g. GH pages)

CF Pages' free unlimited bandwidth and gitops-style deploy might solve for apps that require more than the 100GB software cap of free bandwidth GH has for open source projects.

mscolnick

Thanks for sharing these resources

westurner

> [ FUSE to GitHub FS ]

> Notebooks created from GitHub links have the entire contents of the repository mounted into the notebook's filesystem. This lets you work with files using regular Python file I/O!

Could BusyBox sh compiled to WASM (maybe on emscripten-forge) work with files on this same filesystem?

"Opening a GitHub remote with vscode.dev requires GitHub login? #237371" ... but it works with Marimo and JupyterLite: https://github.com/microsoft/vscode/issues/237371

Does Marimo support local file system access?

jupyterlab-filesystem-access only works with Chrome?: https://github.com/jupyterlab-contrib/jupyterlab-filesystem-...

vscode-marimo: https://github.com/marimo-team/vscode-marimo

"Normalize and make Content frontends and backends extensible #315" https://github.com/jupyterlite/jupyterlite/issues/315

"ENH: Pluggable Cloud Storage provider API; git, jupyter/rtc" https://github.com/jupyterlite/jupyterlite/issues/464

Jupyterlite has read only access to GitHub repos without login, but vscode.dev does not.

Anyways, nbreproduce wraps repo2docker and there's also a repo2jupyterlite.

nbreproduce builds a container to run an .ipynb with: https://github.com/econ-ark/nbreproduce

container2wasm wraps vscode-container-wasm: https://github.com/ktock/vscode-container-wasm

container2wasm: https://github.com/ktock/container2wasm

ge96

wow a python interpreter is "only" 100MB not sure if that's what's happening here

mscolnick

It is much smaller than that, Pyodide is only 2.8mb and the Python stdlib is 2.3mb when zipped

miohtama

There is $300k in bounties if you create under 1MB WebAssembly CPython distribution

https://www.reddit.com/r/Python/comments/1huxrs6/python_runn...

palmfacehn

50k for the 1mb challenge. The rest is to build out the tooling. It looks like they want to run existing ML python libs from within the NEAR blockchain environment.

Wondering why they don't separate concerns here.

ge96

now that's a weissman score

ge96

Oh that's great

bagels

Is that too small or too large in your estimation?

ge96

Wrt web pages supposedly being a couple megabytes it's a big number but at the same time it seems expected with these kind of applications (usually when I see WASM it's a 3D video game)

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