1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275
#![deny(missing_docs)] #![warn(missing_doc_code_examples)] //! Message Worker is a library for Rust for the creation of event-listeners using futures and //! streams. Notably, Message Worker supports non-sync and non-send (i.e. non-thread-safe) //! contexts within listeners. //! //! This is a fairly low-level library that can be used to build a wide-array of stream-processing //! and event-driven systems. It can even be used to build actor systems! //! //! This library must be used in a [tokio](https://tokio.rs/) runtime. //! //! # Examples //! ## Printer //! ``` //! use message_worker::non_blocking::listen; //! use message_worker::{Context, ThreadSafeContext}; //! use std::sync::Arc; //! use anyhow::Result; //! //! let mut rt = tokio::runtime::Runtime::new().unwrap(); //! rt.block_on(async { //! // We don't need any state for this example //! struct EmptyCtx; //! impl Context for EmptyCtx {} impl ThreadSafeContext for EmptyCtx {} //! //! // Create our stream //! let source = tokio_stream::iter(vec![42, 0xff6900, 1337]); //! //! // Create a listener that prints out each item in the stream //! async fn on_item(_ctx: Arc<EmptyCtx>, event: usize) -> Result<()> { //! eprintln!("{}", event); //! Ok(()) //! } //! //! // Start listening //! listen(source, move || EmptyCtx, on_item).await.unwrap(); //! //! /* Prints: //! 42 //! 0xff6900 //! 1337 //! */ //! }) //! ``` //! //! ## Two-way communication //! ``` //! use message_worker::non_blocking::listen; //! use message_worker::{Context, ThreadSafeContext}; //! use std::sync::Arc; //! use anyhow::Result; //! use tokio::sync::RwLock; //! use tokio_stream::StreamExt; //! use tokio_stream::wrappers::ReceiverStream; //! //! let mut rt = tokio::runtime::Runtime::new().unwrap(); //! rt.block_on(async { //! struct BiCtx { output: RwLock<tokio::sync::mpsc::Sender<usize>> } //! impl Context for BiCtx {} impl ThreadSafeContext for BiCtx {} //! //! // Create our stream //! let source = tokio_stream::iter(vec![42, 0xff6900, 1337]); //! //! // Create a listener that outputs each item in the stream multiplied by two //! async fn on_item(ctx: Arc<BiCtx>, event: usize) -> Result<()> { //! let mut output = ctx.output.write().await; //! output.send(event * 2).await?; // Send the output //! Ok(()) //! } //! //! // Connect the number stream to `on_item` //! let (tx, rx) = tokio::sync::mpsc::channel::<usize>(3); //! listen(source, move || BiCtx { //! output: RwLock::new(tx) //! }, on_item); //! //! let mut rx = ReceiverStream::new(rx); //! assert_eq!(rx.next().await, Some(84)); //! assert_eq!(rx.next().await, Some(0x1fed200)); //! assert_eq!(rx.next().await, Some(2674)); //! }) //! ``` //! //! ## Ping-pong (Actors) //! ``` //! use message_worker::non_blocking::listen; //! use message_worker::{Context, ThreadSafeContext}; //! use std::sync::Arc; //! use anyhow::{Result, bail, anyhow}; //! use tokio::sync::RwLock; //! use tokio_stream::wrappers::BroadcastStream; //! use tokio_stream::StreamExt; //! //! let mut rt = tokio::runtime::Runtime::new().unwrap(); //! rt.block_on(async { //! struct ActorCtx { output: RwLock<tokio::sync::broadcast::Sender<Message>> } //! impl Context for ActorCtx {} impl ThreadSafeContext for ActorCtx {} //! //! // Create our messages //! #[derive(Debug, Copy, Clone, Eq, PartialEq)] //! enum Message { Ping, Pong } //! //! //! // Create the ping actor //! async fn ping_actor(ctx: Arc<ActorCtx>, event: Message) -> Result<()> { //! match event { //! Message::Ping => bail!("I'm meant to be the pinger!"), //! Message::Pong => //! ctx.output //! .write().await //! .send(Message::Ping) //! .map_err(|err| anyhow!(err))? //! }; //! Ok(()) //! } //! //! // Create the pong actor //! async fn pong_actor(ctx: Arc<ActorCtx>, event: Message) -> Result<()> { //! match event { //! Message::Ping => //! ctx.output //! .write().await //! .send(Message::Pong) //! .map_err(|err| anyhow!(err))?, //! Message::Pong => bail!("I'm meant to be the ponger!") //! }; //! Ok(()) //! } //! //! // Create our initial stream //! let initial_ping = tokio_stream::iter(vec![Message::Ping]); //! //! // Connect everything together //! let (tx_ping, mut rx_ping) = tokio::sync::broadcast::channel::<Message>(128); //! let (tx_pong, mut rx_pong) = tokio::sync::broadcast::channel::<Message>(128); //! let mut watch_pongs = BroadcastStream::new(tx_ping.clone().subscribe()).map(|msg| msg.unwrap()); //! let mut watch_pings = BroadcastStream::new(tx_pong.clone().subscribe()).map(|msg| msg.unwrap()); //! //! // Start the ping actor //! listen( //! BroadcastStream::new(rx_ping).map(|msg| msg.unwrap()), //! move || ActorCtx { output: RwLock::new(tx_pong) }, //! ping_actor //! ); //! //! // Start the pong actor //! listen( //! initial_ping.chain(BroadcastStream::new(rx_pong).map(|msg| msg.unwrap())), //! move || ActorCtx { output: RwLock::new(tx_ping) }, //! pong_actor //! ); //! //! assert_eq!(watch_pings.next().await, Some(Message::Ping)); //! assert_eq!(watch_pongs.next().await, Some(Message::Pong)); //! assert_eq!(watch_pings.next().await, Some(Message::Ping)); //! assert_eq!(watch_pongs.next().await, Some(Message::Pong)); //! }) //! ``` //! //! ## The Wild Example (calling V8's C++ via Deno within an event listener to run JS) //! ``` //! use message_worker::blocking::listen; //! use message_worker::Context; //! use std::cell::RefCell; //! use deno_core::{JsRuntime, RuntimeOptions}; //! use std::rc::Rc; //! use anyhow::Result; //! use tokio_stream::StreamExt; //! use tokio_stream::wrappers::ReceiverStream; //! //! let mut rt = tokio::runtime::Runtime::new().unwrap(); //! rt.block_on(async { //! struct MockCtx { //! test_res: RefCell<tokio::sync::mpsc::Sender<()>>, //! runtime: RefCell<JsRuntime> //! } //! impl Context for MockCtx {} //! //! let (mut tx, rx) = tokio::sync::mpsc::channel::<()>(1); //! let stream = ReceiverStream::new(rx); //! //! let (test_res_tx, mut test_res) = { //! let (tx, rx) = tokio::sync::mpsc::channel::<()>(1); //! (tx, ReceiverStream::new(rx)) //! }; //! //! async fn mock_handle(ctx: Rc<MockCtx>, _event: ()) -> Result<()> { //! let mut runtime = ctx.runtime.borrow_mut(); //! //! runtime.execute( //! "<test>", //! r#"Deno.core.print(`Got a message!\n`);"# //! )?; //! runtime.run_event_loop().await?; //! //! ctx.test_res.borrow_mut().send(()).await?; //! Ok(()) //! } //! //! listen(stream, move || { //! let runtime: JsRuntime = { //! let tokio_rt = tokio::runtime::Handle::current(); //! tokio_rt.block_on(async { //! let local = tokio::task::LocalSet::new(); //! local.run_until(async { //! let mut runtime = JsRuntime::new(RuntimeOptions { //! module_loader: Some(Rc::new(deno_core::FsModuleLoader)), //! will_snapshot: false, //! ..RuntimeOptions::default() //! }); //! //! runtime.execute( //! "<test>", //! r#"Deno.core.print(`Starting up the JS runtime via C++ FFI and Deno 🤯\n`);"# //! ).unwrap(); //! runtime.run_event_loop().await.unwrap(); //! //! runtime //! }).await //! }) //! }; //! //! MockCtx { //! test_res: RefCell::new(test_res_tx), //! runtime: RefCell::new(runtime) //! } //! }, mock_handle); //! tx.send(()).await.unwrap(); //! //! /* Prints: //! Starting up the JS runtime via C++ FFI and Deno 🤯 //! Got a message! //! */ //! assert_eq!(test_res.next().await, Some(())); //! }) //! ``` //! /// Listeners that perform CPU intensive/blocking tasks or work with non-threadsafe data pub mod blocking; /// Listeners that don't block and work with threadsafe (`Sync` + `Send`) data. pub mod non_blocking; /// This trait needs to be implemented by the item you're using as the state for the listener. /// /// For example, if the listener has no state you can simply go: /// ``` /// use message_worker::Context; /// struct EmptyCtx; /// impl Context for EmptyCtx {} /// ``` /// /// `EmptyCtx` can now be used as the context for your listeners. For mutability inside a `Context` /// you can use [RefCell](https://doc.rust-lang.org/std/cell/struct.RefCell.html)s. The Message Worker /// runtime guarantees that it will never attempt to access your context in parallel from one listener. pub trait Context: 'static {} /// If you are using a [`non_blocking`](non_blocking) listener, this implementation is required /// alongside `Context`. /// /// For mutability inside a `Context` /// you can use [Mutex](https://doc.rust-lang.org/std/sync/struct.Mutex.html)es /// or [RwLock](https://docs.rs/tokio/0.2/tokio/sync/struct.RwLock.html)s. /// The Message Worker runtime guarantees that it will never attempt to access your context /// in parallel from one listener. pub trait ThreadSafeContext: Context + Send + Sync {} /// A predefined context for listeners that don't need any state. pub struct EmptyCtx; impl Context for EmptyCtx {} impl ThreadSafeContext for EmptyCtx {} #[cfg(test)] mod tests {}