6장: Go, Python, 기타 언어에서 Wasm

# 표준 Go 컴파일러 (WASI Preview 1)
GOOS=wasip1 GOARCH=wasm go build -o app.wasm main.go
 
# 결과: 약 5~15MB (런타임 포함)

package main
 
import (
    "fmt"
    "net/http"
    
    spinhttp "github.com/fermyon/spin-go-sdk/http"
)
 
func init() {
    spinhttp.Handle(func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("Content-Type", "application/json")
        
        name := r.URL.Query().Get("name")
        if name == "" {
            name = "World"
        }
        
        fmt.Fprintf(w, `{"message":"Hello, %s!"}`, name)
    })
}
 
func main() {}

# TinyGo로 WASI Preview 2 빌드
tinygo build -target=wasip2 -o app.wasm main.go
 
# 결과: 약 200KB ~ 1MB (표준 Go 대비 1/10 이하)

import json
from typing import Optional
 
# WIT에서 생성된 바인딩
from bindings.exports.example.api import handler
 
class Handler(handler.Handler):
    def handle_request(self, method: str, path: str, body: Optional[bytes]) -> handler.Response:
        if method == "GET" and path == "/api/status":
            return handler.Response(
                status=200,
                headers=[("content-type", "application/json")],
                body=json.dumps({
                    "status": "ok",
                    "language": "Python",
                    "runtime": "componentize-py"
                }).encode()
            )
        
        return handler.Response(
            status=404,
            headers=[("content-type", "application/json")],
            body=json.dumps({"error": "Not Found"}).encode()
        )

# componentize-py 설치
pip install componentize-py
 
# Wasm 컴포넌트로 빌드
componentize-py \
  -d wit/world.wit \
  -w api-handler \
  componentize app \
  -o app.wasm
 
# 결과: 약 10~20MB (CPython 인터프리터 포함)

use pyo3::prelude::*;
 
#[pyfunction]
fn process_data(data: Vec<f64>) -> PyResult<Vec<f64>> {
    // 성능 집약적 로직은 Rust로
    Ok(data.iter().map(|x| x * x + 2.0 * x + 1.0).collect())
}
 
#[pymodule]
fn rust_core(_py: Python, m: &PyModule) -> PyResult<()> {
    m.add_function(wrap_pyfunction!(process_data, m)?)?;
    Ok(())
}

#include <emscripten.h>
#include <stdint.h>
#include <stdlib.h>
 
// JavaScript에서 호출할 수 있도록 export
EMSCRIPTEN_KEEPALIVE
void apply_blur(uint8_t* pixels, int width, int height, int radius) {
    // 간단한 박스 블러 구현
    uint8_t* temp = (uint8_t*)malloc(width * height * 4);
    
    for (int y = 0; y < height; y++) {
        for (int x = 0; x < width; x++) {
            int r = 0, g = 0, b = 0, count = 0;
            
            for (int dy = -radius; dy <= radius; dy++) {
                for (int dx = -radius; dx <= radius; dx++) {
                    int nx = x + dx, ny = y + dy;
                    if (nx >= 0 && nx < width && ny >= 0 && ny < height) {
                        int idx = (ny * width + nx) * 4;
                        r += pixels[idx];
                        g += pixels[idx + 1];
                        b += pixels[idx + 2];
                        count++;
                    }
                }
            }
            
            int idx = (y * width + x) * 4;
            temp[idx] = r / count;
            temp[idx + 1] = g / count;
            temp[idx + 2] = b / count;
            temp[idx + 3] = pixels[idx + 3]; // alpha
        }
    }
    
    // 결과 복사
    for (int i = 0; i < width * height * 4; i++) {
        pixels[i] = temp[i];
    }
    
    free(temp);
}

# Emscripten으로 빌드
emcc image_filter.c \
  -O3 \
  -s EXPORTED_FUNCTIONS='["_apply_blur","_malloc","_free"]' \
  -s EXPORTED_RUNTIME_METHODS='["ccall","cwrap"]' \
  -o image_filter.js
 
# 생성 파일: image_filter.js + image_filter.wasm

// AssemblyScript — TypeScript와 유사하지만
// Wasm 타입에 직접 매핑됩니다
 
export function fibonacci(n: i32): i64 {
  if (n <= 1) return n as i64;
  
  let a: i64 = 0;
  let b: i64 = 1;
  
  for (let i: i32 = 2; i <= n; i++) {
    const temp = a + b;
    a = b;
    b = temp;
  }
  
  return b;
}
 
// 문자열 처리
export function greet(name: string): string {
  return "Hello, " + name + "!";
}

# 설치 및 빌드
npm install assemblyscript
npx asc assembly/index.ts -o build/app.wasm --optimize
 
# 결과: 수 KB ~ 수십 KB (매우 작은 바이너리)

@page "/counter"
 
<h1>Counter</h1>
 
<p>Current count: @currentCount</p>
 
<button @onclick="IncrementCount">Click me</button>
 
@code {
    private int currentCount = 0;
 
    private void IncrementCount()
    {
        currentCount++;
    }
}