wasm-builder

Extism builder

Helper to build Extism plug-ins

Installed components	Version
Extism CLI	0.3.3
Go	1.21.3
TinyGo	0.30.0
Rustc / Cargo	1.74.1
Wasm-pack	0.12.1
Extism-js	1.0.0-rc1

Create a TinyGo plug-in

Generate the project

mkdir hello
cd hello
go mod init hello
go get github.com/extism/go-sdk
touch main.go

Add this source code to main.go:

package main

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

//export hello
func hello() {
    input := pdk.Input()

    message := "🤗 Hello " + string(input)
    
    mem := pdk.AllocateString(message)
    pdk.OutputMemory(mem)
}

func main() {}

Build the wasm plug-in

tinygo build -scheduler=none --no-debug \
-o hello.wasm \
-target wasi main.go

Call the function with the Extism CLI

extism call hello.wasm hello --input "Bob Morane" --wasi
# you should get: 🤗 Hello Bob Morane

Create a Rust plug-in

Generate the project

cargo new --lib hello_demo --name hello
cd hello_demo
cargo add extism-pdk@1.0.0-rc1

Add this section to the Cargo.toml file:

[lib]
crate_type = ["cdylib"]

Replace the source code of srg/lib.rs by this content:

use extism_pdk::*;

#[plugin_fn]
pub fn hello(name: String) -> FnResult<String> {
    Ok(format!("👋 Hello, {}!", name))
}

Build the wasm plug-in

cargo clean
cargo build --release --target wasm32-wasi

Call the function with the Extism CLI

extism call ./target/wasm32-wasi/release/hello.wasm hello --input "Bob Morane" --wasi
# you should get: 👋 Hello, Bob Morane!