simple_wasi_app.md

WASI standalone app

In this example, we demonstrate how to build a standalone WASM application from the rust application.

Prerequisites

If you simply want a wasm bytecode file to test as a container image, you can skip the building process and just download the wasm file here.

If you have not done so already, follow these simple instructions to install Rust and rustwasmc toolchain.

Download example code

git clone git@github.com:second-state/wasm-learning.git
cd cli/wasi

Build the WASM bytecode

rustwasmc build

The wasm bytecode application is in pkg/wasi_example_main.wasm file. You can now publish and use it as a container image.

Apply executable permission on the Wasm bytecode

chmod +x pkg/wasi_example_main.wasm

Create Dockerfile

Create a file called Dockerfile in the pkg folder with the following content:

FROM scratch
ADD wasi_example_main.wasm .
CMD ["wasi_example_main.wasm"]

Create container image

This example uses docker to build image. You can use any other tools to create container image.

Here is an example of creating container image and publishing the wasm bytecode file to the public Docker hub.

sudo docker build -f Dockerfile -t hydai/wasm-wasi-example:latest .
sudo docker push hydai/wasm-wasi-example:latest

Run an instance with created container images

Please refer to the section Create container config.