run the cpython interpreter inside gabagool

Author: friendlymatthew

.gitignore

@@ -8,3 +8,5 @@ programs/*.wat
 !programs/fibonacci.wat
 !programs/add.wat
 !programs/stair_climb.wat
+examples/python/python.wasm
+examples/python/lib/

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 members = ["gabagool", "gabagool-debug-adapter", "gabagool-wasip1"]
-exclude = ["programs-wasi"]
+exclude = ["programs-wasi", "examples/game-of-life", "examples/python"]
 resolver = "2"
 
 [workspace.package]

examples/python/Cargo.lock

@@ -0,0 +1,8 @@
+[package]
+name = "python"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+gabagool = { path = "../../gabagool" }
+gabagool-wasip1 = { path = "../../gabagool-wasip1" }

examples/python/Cargo.toml

@@ -0,0 +1,13 @@
+# python
+
+This demo runs the CPython 3.13 interpreter compiled to wasm inside `gabagool`. It executes Python scripts by loading `python.wasm` with WASI P1 support.
+
+# Usage
+
+```sh
+# fetch the interpreter and stdlib
+uv run download_python.py
+
+# pass in any python script
+cargo r --release hello.py
+```

examples/python/README.md

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+import io
+import sys
+import zipfile
+from pathlib import Path
+from urllib.request import urlopen
+
+VERSION = "3.13.12"
+WASI_SDK = "24"
+URL = f"https://github.com/brettcannon/cpython-wasi-build/releases/download/v{VERSION}/python-{VERSION}-wasi_sdk-{WASI_SDK}.zip"
+
+script_dir = Path(__file__).resolve().parent
+
+if (script_dir / "python.wasm").exists() and (script_dir / "lib").exists():
+    sys.exit(0)
+
+with urlopen(URL) as resp:
+    data = resp.read()
+
+with zipfile.ZipFile(io.BytesIO(data)) as zf:
+    zf.extractall(script_dir)

examples/python/download_python.py

@@ -0,0 +1 @@
+print("hello world")

examples/python/hello.py

@@ -0,0 +1,31 @@
+use std::env;
+use std::fs;
+
+use gabagool::{Module, Store};
+use gabagool_wasip1::WasiCtx;
+
+fn run() {
+    let manifest_dir = env!("CARGO_MANIFEST_DIR");
+    let script = env::args().nth(1).unwrap_or_else(|| "hello.py".into());
+
+    let wasm = fs::read(format!("{manifest_dir}/python.wasm")).unwrap();
+    let module = Module::new(&wasm).unwrap();
+    let mut store = Store::new();
+
+    let mut wasi = WasiCtx::new()
+        .with_args(&["python", &script])
+        .preopen("/", manifest_dir);
+
+    let imports = wasi.imports(&mut store, &module);
+    let instance = store.instantiate(&module, imports).unwrap();
+    let exit_code = wasi.run(&mut store, instance).unwrap();
+
+    if exit_code != 0 {
+        eprintln!("python exited with code {exit_code}");
+    }
+}
+
+fn main() {
+    let builder = std::thread::Builder::new().stack_size(64 * 1024 * 1024);
+    builder.spawn(run).unwrap().join().unwrap();
+}