This example illustrates how to use a wasi:http component as an application for nginx unit. nginx unit is able to directly instantiate WASM components which adhere to the wasi:http specification and utilizes a WASM runtime to server requests.

Installation

You need wasm-tools, nginx unit and the nginx unit wasm support. On Mac OS X simply do:

brew install wasm-tools
brew install nginx/unit/unit nginx/unit/unit-wasm

Instead of using curl to communicate with nginx unit, httpie can be useful as it has built-in support for json.

brew install httpie

You also need to install the wit-bindgen utilities with support for moonbit.

The best way is to get them is probably:

cargo install --git https://github.com/peter-jerry-ye/wit-bindgen.git\#moonbit wit-bindgen-cli

Running

There is a Makefile which fetches the WIT dependencies, builds the WIT bindings, builds the moonbit WASM and converts it to a component.

You need to start nginx unit:

unitd --control 127.0.0.1:9090 --no-daemon --log $(pwd)/unit.log

and build the WASM component:

make build
make component

When that succeeded you can configure nginx unit (unit.config.json contains a hard coded path to your WASM file, please adopt it accordingly):

# update the configuration
cat unit.conf.json | http PUT :9090/config
# restart the app
http :9090/control/applications/demo/restart

and when that is done you can finally do:

http :8091/

HTTP/1.1 200 OK
Date: Sun, 19 Jan 2025 19:39:29 GMT
Server: Unit/1.34.1
Transfer-Encoding: chunked

Hello, World

The last steps can also be achieved by issuing:

make restart-unit