feat: shuttle-serenity initial commit poc (#429)

* feat: shuttle-serenity initial commit poc

* remove shuttle-service

* refactor: drop more shuttle_service stuff

* refactor: drop default serenity framework

* misc: add wasm32-wasi to nix shell

* refactor: cargo sort

* refactor: cargo fmt

Co-authored-by: chesedo <pieter@chesedo.me>

Cargo.toml

@@ -12,6 +12,7 @@ members = [
 exclude = [
   "e2e",
   "examples",
+  "plugins",
   "resources/aws-rds",
   "resources/persist",
   "resources/secrets",

plugins/Cargo.toml

@@ -0,0 +1,5 @@
+[workspace]
+members = [
+  "serenity/wasm",
+  "serenity/runtime"
+]

plugins/serenity/Makefile

@@ -0,0 +1,13 @@
+.PHONY: wasm runtime
+
+all: wasm runtime
+
+wasm:
+	cd wasm; cargo build --target wasm32-wasi
+	cp ../target/wasm32-wasi/debug/shuttle_serenity.wasm runtime/bot.wasm
+
+test: wasm
+	cd runtime; cargo test -- --nocapture
+
+runtime:
+	cd runtime; cargo build

plugins/serenity/runtime/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "shuttle-runtime"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[[bin]]
+name = "shuttle-runtime"
+
+[dependencies]
+async-trait = "0.1.58"
+
+tokio = { version = "1.20.1", features = [ "full" ] }
+
+cap-std = "*"
+wasmtime = "*"
+wasmtime-wasi = "*"
+wasi-common = "*"
+
+serenity = { version = "0.11.5", default-features = false, features = ["client", "gateway", "rustls_backend", "model"] }

plugins/serenity/runtime/README.md

@@ -0,0 +1,13 @@
+# `shuttle-runtime`
+
+## How to run
+
+```bash
+$ cd ..; make wasm
+$ DISCORD_TOKEN=xxx BOT_SRC=bot.wasm cargo run
+```
+
+## Running the tests
+```bash
+$ cd ..; make test
+```

plugins/serenity/runtime/src/lib.rs

@@ -0,0 +1,153 @@
+use std::fs::File;
+use std::io::{Read, Write};
+use std::os::unix::prelude::RawFd;
+use std::path::Path;
+use std::sync::Arc;
+
+use async_trait::async_trait;
+
+use serenity::{model::prelude::*, prelude::*};
+
+use cap_std::os::unix::net::UnixStream;
+use wasi_common::file::FileCaps;
+use wasmtime::{Engine, Linker, Module, Store};
+use wasmtime_wasi::sync::net::UnixStream as WasiUnixStream;
+use wasmtime_wasi::{WasiCtx, WasiCtxBuilder};
+
+pub struct BotBuilder {
+    engine: Engine,
+    store: Store<WasiCtx>,
+    linker: Linker<WasiCtx>,
+    src: Option<File>,
+}
+
+impl BotBuilder {
+    pub fn new() -> Self {
+        let engine = Engine::default();
+
+        let mut linker: Linker<WasiCtx> = Linker::new(&engine);
+        wasmtime_wasi::add_to_linker(&mut linker, |s| s).unwrap();
+
+        let wasi = WasiCtxBuilder::new()
+            .inherit_stdio()
+            .inherit_args()
+            .unwrap()
+            .build();
+
+        let store = Store::new(&engine, wasi);
+
+        Self {
+            engine,
+            store,
+            linker,
+            src: None,
+        }
+    }
+
+    pub fn src<P: AsRef<Path>>(mut self, src: P) -> Self {
+        self.src = Some(File::open(src).unwrap());
+        self
+    }
+
+    pub fn build(mut self) -> Bot {
+        let mut buf = Vec::new();
+        self.src.unwrap().read_to_end(&mut buf).unwrap();
+        let module = Module::new(&self.engine, buf).unwrap();
+
+        for export in module.exports() {
+            println!("export: {}", export.name());
+        }
+
+        self.linker.module(&mut self.store, "bot", &module).unwrap();
+        let inner = BotInner {
+            store: self.store,
+            linker: self.linker,
+        };
+        Bot {
+            inner: Arc::new(Mutex::new(inner)),
+        }
+    }
+}
+
+pub struct BotInner {
+    store: Store<WasiCtx>,
+    linker: Linker<WasiCtx>,
+}
+
+impl BotInner {
+    pub async fn message(&mut self, new_message: &str) -> Option<String> {
+        let (mut host, client) = UnixStream::pair().unwrap();
+        let client = WasiUnixStream::from_cap_std(client);
+
+        self.store
+            .data_mut()
+            .insert_file(3, Box::new(client), FileCaps::all());
+
+        host.write_all(new_message.as_bytes()).unwrap();
+        host.write(&[0]).unwrap();
+
+        println!("calling inner EventHandler message");
+        self.linker
+            .get(&mut self.store, "bot", "__SHUTTLE_EventHandler_message")
+            .unwrap()
+            .into_func()
+            .unwrap()
+            .typed::<RawFd, (), _>(&self.store)
+            .unwrap()
+            .call(&mut self.store, 3)
+            .unwrap();
+
+        let mut resp = String::new();
+        host.read_to_string(&mut resp).unwrap();
+
+        if resp.is_empty() {
+            None
+        } else {
+            Some(resp)
+        }
+    }
+}
+
+pub struct Bot {
+    inner: Arc<Mutex<BotInner>>,
+}
+
+impl Bot {
+    pub fn builder() -> BotBuilder {
+        BotBuilder::new()
+    }
+
+    pub fn new<P: AsRef<Path>>(src: P) -> Self {
+        Self::builder().src(src).build()
+    }
+
+    pub async fn into_client(self, token: &str, intents: GatewayIntents) -> Client {
+        Client::builder(&token, intents)
+            .event_handler(self)
+            .await
+            .unwrap()
+    }
+}
+
+#[async_trait]
+impl EventHandler for Bot {
+    async fn message(&self, ctx: Context, new_message: Message) {
+        let mut inner = self.inner.lock().await;
+        if let Some(resp) = inner.message(new_message.content.as_str()).await {
+            new_message.channel_id.say(&ctx.http, resp).await.unwrap();
+        }
+    }
+}
+
+#[cfg(test)]
+pub mod tests {
+    use super::*;
+
+    #[tokio::test]
+    async fn bot() {
+        let bot = Bot::new("bot.wasm");
+        let mut inner = bot.inner.lock().await;
+        assert_eq!(inner.message("not !hello").await, None);
+        assert_eq!(inner.message("!hello").await, Some("world!".to_string()));
+    }
+}

plugins/serenity/runtime/src/main.rs

@@ -0,0 +1,19 @@
+use std::env;
+use std::io;
+
+use serenity::prelude::*;
+
+use shuttle_runtime::Bot;
+
+#[tokio::main]
+async fn main() -> io::Result<()> {
+    let intents = GatewayIntents::GUILD_MESSAGES | GatewayIntents::MESSAGE_CONTENT;
+
+    let token = env::var("DISCORD_TOKEN").unwrap();
+    let src = env::var("BOT_SRC").unwrap();
+
+    let mut client = Bot::new(src).into_client(token.as_str(), intents).await;
+    client.start().await.unwrap();
+
+    Ok(())
+}

plugins/serenity/wasm/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "shuttle-serenity"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[lib]
+crate-type = [ "cdylib" ]
+
+[dependencies]

plugins/serenity/wasm/src/lib.rs

@@ -0,0 +1,37 @@
+use std::fs::File;
+use std::io::{Read, Write};
+use std::os::wasi::prelude::*;
+
+pub fn handle_message(message: &str) -> Option<String> {
+    if message == "!hello" {
+        Some("world!".to_string())
+    } else {
+        None
+    }
+}
+
+#[no_mangle]
+#[allow(non_snake_case)]
+pub extern "C" fn __SHUTTLE_EventHandler_message(fd: RawFd) {
+    println!("inner handler awoken; interacting with fd={fd}");
+
+    let mut f = unsafe { File::from_raw_fd(fd) };
+
+    let mut buf = Vec::new();
+    let mut c_buf = [0; 1];
+    loop {
+        f.read(&mut c_buf).unwrap();
+        if c_buf[0] == 0 {
+            break;
+        } else {
+            buf.push(c_buf[0]);
+        }
+    }
+
+    let msg = String::from_utf8(buf).unwrap();
+    println!("got message: {msg}");
+
+    if let Some(resp) = handle_message(msg.as_str()) {
+        f.write_all(resp.as_bytes()).unwrap();
+    }
+}

shell.nix

@@ -11,7 +11,9 @@ in
       pkg-config
     ];
     buildInputs = with nixpkgs; [
-      (rustChannelOf{ channel = "1.63.0"; }).rust
+      ((rustChannelOf{ channel = "1.63.0"; }).rust.override {
+        targets = ["wasm32-wasi"];
+      })
       rust-analyzer
       cargo-watch
       terraform