overlord/plugin-sample-go/README.md

Sample Go WASM Plugin (sample)

This sample lives at the repo root and builds a WASI-compatible Go plugin.

Files to include in the plugin zip

At the root of the zip:

• sample.wasm
• sample.html
• sample.css
• sample.js

Build the WASM

Recommended: Go WASI (most compatible with wazero)

1. Build the WASM with Go 1.21+:

   GOOS=wasip1 GOARCH=wasm go build -o sample.wasm ./wasm

2. Optional TinyGo fallback:

   tinygo build -o sample.wasm -target wasi -scheduler=none -gc=leaking ./wasm

Create the zip

Create a zip named sample.zip containing:

• sample.wasm
• sample.html
• sample.css
• sample.js

Then place sample.zip in Overlord-Server/plugins.

Open the UI

Navigate to:

• /plugins/sample?clientId=<CLIENT_ID>

Click "Send event" and the WASM plugin will echo back to the server logs.

OS detection (Windows-only logic)

The plugin receives host metadata in the init payload. The sample plugin shows how to detect the host OS and branch logic (see plugin-sample-go/wasm/main.go). For example:

• If host.os == "windows", you can safely run Windows-only flows (e.g., WinAPI-backed behavior).
• Otherwise, skip or provide a fallback path.