Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

WebAssembly: Adding Python support to WASM language runtimes

wasmlabs.dev

Post reply on HN
Print view View original

1–10 of 88 posts

Re: WebAssembly: Adding Python support to WASM language runtimes

#3

Post by simonw »

This looks very promising!

The thing I most want to solve right now is this: I want to write a regular Python application that can safely execute untrusted Python code in a WASM sandbox as part of its execution.

I want to do this so I can let end users customize my web applications in weird and interesting ways by pasting their own Python code into a textarea - think features like "run this Python code to transform my stored data" - without them being able to break my system.

This feels like it should be pretty easy with WebAssembly! It's the classic code sandboxing problem - long a big challenge in Python world - finally solved in a robust way.

I've been finding it surprisingly hard to get a proof-of-concept of this working though.

Essentially I want to be able to do this, in my regular Python code:

    import some_webassembly_engine

    python = some_webassembly_engine.load(
        "python.wasm",
        max_cpu_time_in_seconds=3.0,
        max_allowed_memory_in_bytes=32000000
    )
    result = python.execute("3 + 5")
I've not yet figured out the incantations I need to actually do this - in particular the limits on CPU and memory time.

I posed this question on Mastodon recently and Jim Kring put together this demo, which gets most of the way there (albeit using an old Python 3.6 build): https://github.com/jimkring/python-sandbox-wasm

It doesn't feel like this should be as hard to figure out as it is!

Re: WebAssembly: Adding Python support to WASM language runtimes

#5

Post by brrrrrm »

the issue right now with Python support in WASM (at least for machine learning, the main driver of the language) is that Python is largely a wrapper language and none the utilities that make it so powerful (numpy, PyTorch, JAX) work particularly well in wasm, since it's so limited performance-wise (no FMA, no GPU support).

I'm excited for pairing wasm with WebGPU, which will likely unblock these projects from building support for the web/untrusted ecosystem. A useful project would be one that makes this integration really easy to build today and a flip of the switch to turn on in the future.

Re: WebAssembly: Adding Python support to WASM language runtimes

#6

Post by m00dy »

brrrrrm wrote: post #5

the issue right now with Python support in WASM (at least for machine learning, the main driver of the language) is that Python is largely a wrapper language and none the utilities that make it so powerful (numpy, PyTorch, JAX) work particularly well in wasm, since it's so limited performance-wise (no FMA, no GPU support). I'm excited for pairing wasm with WebGPU, which will likely unblock these projects from buildin…

I have integrated pyodide + webgpu recently. (you can do matmul using webgpu's compute pipeline). The real problem is that browser tabs have 4gb max memory size. So, training neural networks on this stack is almost impossible. ( I don't even want to mention pyTorch's dependency hell).

Re: WebAssembly: Adding Python support to WASM language runtimes

#7

Post by chc »

c120 wrote: post #4

So for someone who has python installed locally, what's the point? Is it just the sandbox or is there anything else I'm missing?

If you're just looking to run trusted scripts locally, there isn't much point. If you're running a system that uses wasm, this means you can now easily support Python.

Re: WebAssembly: Adding Python support to WASM language runtimes

#8

Post by samsquire »

simonw wrote: post #3

This looks very promising! The thing I most want to solve right now is this: I want to write a regular Python application that can safely execute untrusted Python code in a WASM sandbox as part of its execution. I want to do this so I can let end users customize my web applications in weird and interesting ways by pasting their own Python code into a textarea - think features like "run this Python code to transform m…

This would be great. And with an exposeable API for safety a memory safe API that could be exposed to wasm applications. And rate limited.

Re: WebAssembly: Adding Python support to WASM language runtimes

#10

Post by mike_hearn »

simonw wrote: post #3

This looks very promising! The thing I most want to solve right now is this: I want to write a regular Python application that can safely execute untrusted Python code in a WASM sandbox as part of its execution. I want to do this so I can let end users customize my web applications in weird and interesting ways by pasting their own Python code into a textarea - think features like "run this Python code to transform m…

FWIW although it's not WebAssembly based, you can do that with GraalVM. It has a concept of language contexts which can be sandboxed including those constraints. There are two caveats:

1. Sandboxing for CPU time and max allowed memory requires the enterprise edition, so you'd have to pay for it.

2. The Python engine isn't 100% compatible with regular Python, although that may not matter for your use case as the compatibility is pretty good and issues mostly show up around extension modules.

Post reply on HN