Creating Plugins

This guide covers how to build, package, and install a Windshift plugin.

Prerequisites

• An Extism-compatible language SDK (Rust, Go, JavaScript, C, etc.)
• Basic understanding of WebAssembly

Extism provides PDKs (Plugin Development Kits) for multiple languages. See extism.org for the full list.

Project Structure

my-plugin/
├── manifest.json      # Plugin metadata and extensions
├── src/               # Plugin source code
├── plugin.wasm        # Compiled WASM binary
└── index.html         # Optional UI (for iframe extensions)

Manifest

Every plugin requires a manifest.json:

{
  "name": "my-plugin",
  "version": "1.0.0",
  "description": "What this plugin does",
  "entryPoint": "plugin.wasm",
  "extensions": []
}

Fields

Extensions

To add a UI tab in the admin panel:

{
  "extensions": [
    {
      "point": "admin.tab",
      "id": "my-plugin-tab",
      "label": "My Plugin",
      "displayMode": "iframe",
      "component": "index.html",
      "group": "Tools"
    }
  ]
}

Writing Plugin Code

Plugins export functions that Windshift calls, and import host functions to interact with the platform.

Example (Go with Extism PDK)

package main

import (
    "github.com/extism/go-pdk"
)

//export run
func run() int32 {
    // Call a host function
    pdk.Log(pdk.LogInfo, "Plugin executing")

    // Read input
    input := pdk.Input()

    // Do work...

    // Write output
    pdk.OutputString("done")
    return 0
}

func main() {}

Example (JavaScript with Extism PDK)

function run() {
  Host.log("info", "Plugin executing");

  const input = Host.inputString();

  // Do work...

  Host.outputString("done");
  return 0;
}

module.exports = { run };

Building

Compile your plugin to a WASM binary using the Extism toolchain for your language:

# Go
tinygo build -o plugin.wasm -target wasi .

# Rust
cargo build --target wasm32-wasi --release
cp target/wasm32-wasi/release/my_plugin.wasm plugin.wasm

# JavaScript (using Extism JS PDK)
extism-js src/index.js -o plugin.wasm

Installing

Place the plugin directory (containing manifest.json and plugin.wasm) in Windshift's plugin directory. Windshift scans for plugins at startup.

Plugins can be enabled/disabled from the admin panel without restarting the server.

Resource Limits

Plugins run with these default constraints:

Plugins that exceed these limits are terminated automatically.