hello-wasm-world

To create the wasm:

py2wasm hello-wasm-world.py -o hello-wasm-world.wasm

To run the wasm:

wasmer run hello-wasm-world.wasm

Instructions for installing wasmer: https://docs.wasmer.io/install

Docker

Why?
Docker and WASM are different layers of abstraction. If Docker is a "container for the OS", then WASM would be a "container for the application". That leads to the conclusion that you can prescind from Docker altogether, theoretically. However, in the real world, there are more factors at play: orchestration and scaling (there's still no k8s equivalent for wasm, afaik), developer experience, maturity (the wasm ecosystem is relatively young), cost of change, and "politics". So, I think as of now, if some organization, that is already running microservices, were to use WASM, it would do it with Docker.

How does Docker work with WASM?
cli <-> dockerd <-> containerd <-> shim <-> wasm rt (replacing runc) <-> registry

To create the wasm docker image:

docker build -t kcandidate/hello-wasm-world:v1 --platform wasi/wasm32 .

To use a wasm runtime for docker, follow these instructions: https://docs.docker.com/engine/daemon/alternative-runtimes/. But those instructions are incomplete (as of 2024/12/13).
The daemon configuration file is /etc/docker/daemon.json:

{
  "features": {
    "containerd-snapshotter": true
  }
}

To build the wasmtime binary, you'll need protobuf-compiler and libseccomp-dev which are not present in the build stage image used in the Docker docs. Alternatively, you can just get the precompiled binary from https://github.com/containerd/runwasi/releases

docker build --output . - <<EOF
FROM rust:latest as build
RUN apt update && apt install -y protobuf-compiler libseccomp-dev
RUN cargo install \
    --git https://github.com/containerd/runwasi.git \
    --bin containerd-shim-wasmtime-v1 \
    --root /out \
    containerd-shim-wasmtime
FROM scratch
COPY --from=build /out/bin /
EOF

To run the wasm docker image:

docker run --runtime=io.containerd.wasmtime.v1 --platform=wasi/wasm kcandidate/hello-wasm-world:v1

Results

Running python hello-wasm-world.py:

Elapsed time for range sum: 0.001385 seconds
Pystone(1.1) time for 50000 passes = 0.124373
This machine benchmarks at 402016 pystones/second

Running wasmer run hello-wasm-world.wasm:

Elapsed time for range sum: 0.000775 seconds
Pystone(1.1) time for 50000 passes = 0.227372
This machine benchmarks at 219904 pystones/second

Running docker run --runtime=io.con tainerd.wasmtime.v1 --platform=wasi/wasm32 kcandidate/hello-wasm-world:v1:

Elapsed time for range sum: 0.000921 seconds
Pystone(1.1) time for 50000 passes = 0.238069
This machine benchmarks at 210023 pystones/second