ImportError with NumPy when running matrix_math example

[erlingto]

ImportError with NumPy when running matrix_math example

[dicej]

Ohh, does this mean I will only be able to use "modified" packages with this?

Pure Python packages should work straight from e.g. pypi.org. Packages which contain native extensions (such as NumPy) must be built for WASI (i.e. the Mac, Windows, and Linux builds won't work). Some day, package maintainers will be able to publish WASI builds to pypi.org alongside the existing Mac, Windows, and Linux builds, but we're not there yet. Hence the wasi-wheels repo linked to in the instructions.

These are the steps im doing (From the "\examples\matrix-math" directory):

* cargo install --version 18.0.0 wasmtime-cli

* pip install componentize-py==0.13.3

* curl -o numpy-wasi.tar.gz https://github.com/dicej/wasi-wheels/releases/download/v0.0.1/numpy-wasi.tar.gz  (my terminal wont accept -OL for some reason, but these two steps should just be downloading and unpacking the file right?)

* tar xf numpy-wasi.tar.gz

Then when im running: "componentize-py -d ../../wit -w matrix-math componentize app -o matrix-math.wasm"

That all looks reasonable to me. I don't have a Windows machine handy at the moment, but I'll give it a try when I have a chance.

[dicej]

Assuming you've followed the directions in https://github.com/bytecodealliance/componentize-py/blob/main/examples/matrix-math/README.md, it actually makes sense you'd get that error when running python app.py directly, because numpy-wasi.tar.gz only has .so files built for WASI, and your native python won't be able to load them.

I just tried following the directions in that README.md and it worked for me. What platform are you using? Does it help to use a virtual environment (e.g. python3 -m venv .venv && source .venv/bin/activate before running the other instructions)?

[erlingto]

Ohh, does this mean I will only be able to use "modified" packages with this?

I just reinstalled Python and attempted the example again.

These are the steps im doing (From the "\examples\matrix-math" directory):

• cargo install --version 18.0.0 wasmtime-cli
• pip install componentize-py==0.13.3
• curl -o numpy-wasi.tar.gz https://github.com/dicej/wasi-wheels/releases/download/v0.0.1/numpy-wasi.tar.gz (my terminal wont accept -OL for some reason, but these two steps should just be downloading and unpacking the file right?)
• tar xf numpy-wasi.tar.gz

Then when im running:
"componentize-py -d ../../wit -w matrix-math componentize app -o matrix-math.wasm"

I get the same error as before, im on a windows computer at the moment running the commands from Command Prompt . Might try to test the example on a different computer tomorrow.

[dicej]

Okay, I managed to reproduce this on Windows; I'll dig into it.

[dicej]

Ugh, looks like a back-slash-vs-forward-slash issue in the paths wit-component is generating to populate the dlopen table. I guess this has probably never worked right on Windows 🤦

Thanks for reporting this. I'll start working on a fix.

[dicej]

This should be fixed in #93. I'll be releasing v0.13.4 once that's merged and CI finishes.

[dicej]

I've released v0.13.4 with the fix; please let me know if you still have any issues.

[erlingto]

Great, Thanks! I will test it tommorow :)