Add logging, graceful shutdown, webserver with websockets

Cargo.toml

@@ -5,4 +5,12 @@ authors = ["Sam Willcocks <sam@wlcx.cc>"]
 edition = "2018"
 
 [dependencies]
-    rand = "0.6.5"
+    rand = "0.6.5"
+    typed-html = "0.1.1"
+    warp = "0.1.13"
+    futures = "0.1.25"
+    log = "0.4.6"
+    simplelog = "0.5.3"
+    crossbeam-channel = "0.3.8"
+    ctrlc = "3.1.1"
+    tokio = "0.1.15"

src/adaptors.rs

@@ -1,49 +1,60 @@
-use crate::{TallyState, Channel};
-use std::sync::mpsc;
-use std::sync::mpsc::{Sender, Receiver};
-use std::thread;
-use std::time::Duration;
+use crate::common::Waitable;
+use crate::{Channel, TallyState};
+use crossbeam_channel::{Receiver, Sender};
 use rand::prelude::*;
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::Duration;
 
 /// An Adaptor interfaces to a system providing tally information, e.g. a BlackMagic ATEM
-pub trait Adaptor {
+pub trait Adaptor: Waitable {
     /// Run the adaptor, returning a channel receiver which receives TallyStates
     fn run(&mut self) -> Receiver<TallyState>;
 }
 
 pub struct FakeAdaptor {
     numchannels: u8,
-    thread: Option<thread::JoinHandle<()>>
+    thread: Option<thread::JoinHandle<()>>,
 }
+
 impl FakeAdaptor {
     pub fn new(numchannels: u8) -> FakeAdaptor {
-        return FakeAdaptor{
+        return FakeAdaptor {
             numchannels: numchannels,
-            thread: None
-        }
+            thread: None,
+        };
     }
 
     fn _run(numchannels: u8, sender: Sender<TallyState>) {
         println!("Hello, I have {} channels", numchannels);
         loop {
-            let state = TallyState{
+            let state = TallyState {
                 on_air: Channel(Some(rand::thread_rng().gen_range(0, numchannels))),
                 preview: Channel(Some(rand::thread_rng().gen_range(0, numchannels))),
             };
-            sender.send(state).unwrap();
-            thread::sleep(Duration::new(rand::thread_rng().gen_range(0,5), 0));
+            if let Err(_) = sender.send(state) {
+                log::info!("Fakeadaptor shutting down!");
+                break;
+            };
+            thread::sleep(Duration::new(rand::thread_rng().gen_range(0, 5), 0));
         }
     }
 }
 
+impl Waitable for FakeAdaptor {
+    fn get_joinhandle(self) -> Option<JoinHandle<()>> {
+        self.thread
+    }
+}
+
 impl Adaptor for FakeAdaptor {
     fn run(&mut self) -> Receiver<TallyState> {
         println!("arse");
-        let (tx, rx): (Sender<TallyState>, Receiver<TallyState>) = mpsc::channel();
+        let (tx, rx) = crossbeam_channel::unbounded::<TallyState>();
         let thread_numchannels = self.numchannels.clone();
         self.thread = Some(thread::spawn(move || {
             FakeAdaptor::_run(thread_numchannels, tx);
         }));
         return rx;
     }
-}
+}

src/common.rs

@@ -0,0 +1,13 @@
+use std::thread;
+
+pub trait Waitable: Sized {
+    fn get_joinhandle(self) -> Option<thread::JoinHandle<()>>;
+
+    fn wait(self) {
+        if let Some(handle) = self.get_joinhandle() {
+            handle.join().expect("Couldn't join on thread!");
+        } else {
+            log::warn!("Tried to wait on non-existent thread!");
+        }
+    }
+}

src/drivers.rs

@@ -1,22 +1,27 @@
+use crate::common::Waitable;
 use crate::TallyState;
 
-use std::sync::mpsc;
-use std::sync::mpsc::{Sender, Receiver};
+use crossbeam_channel::{Receiver, Sender};
 use std::thread;
 
 /// A Driver displays the Tallies on a physical tally system.
-pub trait Driver {
+pub trait Driver: Waitable {
     /// Run the driver, returning a channel sender which takes TallyStates
     fn run(&mut self) -> Sender<TallyState>;
 }
 
 pub struct FakeDriver {
-    thread: Option<thread::JoinHandle<()>>
+    thread: Option<thread::JoinHandle<()>>,
 }
 
+impl Waitable for FakeDriver {
+    fn get_joinhandle(self) -> Option<thread::JoinHandle<()>> {
+        self.thread
+    }
+}
 impl Driver for FakeDriver {
     fn run(&mut self) -> Sender<TallyState> {
-        let (tx, rx): (Sender<TallyState>, Receiver<TallyState>) = mpsc::channel();
+        let (tx, rx) = crossbeam_channel::bounded::<TallyState>(1);
         self.thread = Some(thread::spawn(move || {
             FakeDriver::_run(rx);
         }));
@@ -26,15 +31,18 @@ impl Driver for FakeDriver {
 
 impl FakeDriver {
     pub fn new() -> FakeDriver {
-        FakeDriver{
-            thread: None
-        }
+        FakeDriver { thread: None }
     }
 
     fn _run(rx: Receiver<TallyState>) {
         loop {
-            let state = rx.recv().unwrap();
-            println!("{}", state);
+            if let Ok(state) = rx.recv() {
+                println!("{}", state);
+            } else {
+                // channel has been disconnected, shutdown.
+                log::info!("Fakedriver shutting down...");
+                return;
+            }
         }
     }
-}
+}

src/main.rs

@@ -1,8 +1,13 @@
 mod adaptors;
+mod common;
 mod drivers;
+mod web;
 use crate::adaptors::{Adaptor, FakeAdaptor};
 use crate::drivers::{Driver, FakeDriver};
+use crossbeam_channel::{select, Receiver};
+use simplelog::{Config, LevelFilter, TermLogger};
 use std::fmt;
+use web::WebServer;
 
 #[derive(Clone)]
 pub struct Channel(Option<u8>);
@@ -34,20 +39,51 @@ struct Server<T: Adaptor, U: Driver> {
 }
 
 impl<T: Adaptor, U: Driver> Server<T, U> {
-    fn run(&mut self) {
+    fn run(mut self, signal_rx: Receiver<()>) {
         let rx = self.adaptor.run();
         let tx = self.driver.run();
+        let webaddr = ([127, 0, 0, 1], 3000).into();
+        log::info!("Webserver starting on: {}", webaddr);
+        let web = WebServer::run(webaddr);
         loop {
-            tx.send(rx.recv().unwrap()).unwrap();
+            select! {
+                recv(signal_rx) -> _ => {
+                    log::info!("Signal received, quitting!");
+                    // signal webserver to shutdown and wait for exit..
+                    web.shutdown();
+                    // Drop the driver channel, and wait for it to shutdown...
+                    drop(tx);
+                    self.driver.wait();
+
+                    // ...and do the same for the adaptor.
+                    drop(rx);
+                    self.adaptor.wait();
+
+                    // We're done, break loop and return.
+                    break;
+                },
+                recv(rx) -> state => {
+                    tx.send(state.unwrap()).unwrap();
+                }
+            }
         }
     }
 }
 
 fn main() {
-    let mut s = Server {
+    TermLogger::init(LevelFilter::Debug, Config::default()).unwrap();
+
+    let (signal_tx, signal_rx) = crossbeam_channel::bounded::<()>(1);
+    ctrlc::set_handler(move || {
+        log::info!("Received interrupt. Shutting down...");
+        signal_tx.send(()).expect("Error sending to signal channel");
+    })
+    .expect("Error setting signal handler");
+
+    let s = Server {
         adaptor: FakeAdaptor::new(8),
         driver: FakeDriver::new(),
     };
 
-    s.run();
+    s.run(signal_rx);
 }

src/web.rs

@@ -0,0 +1,78 @@
+use futures::stream;
+use futures::sync::oneshot::{channel, Sender};
+use std::sync::{Arc, Mutex};
+use std::thread;
+use typed_html::dom::DOMTree;
+use typed_html::html;
+use warp::filters::ws::Message;
+use warp::{Filter, Future, Stream};
+
+fn build_template() -> DOMTree<String> {
+    html!(
+        <html>
+            <head>
+                <title>"OpenTally Control"</title>
+                <script src="/script.js" type="text/javascript"></script>
+            </head>
+            <body>
+                <h1>"OpenTally Control"</h1>
+            </body>
+        </html>
+    )
+}
+
+pub struct WebServer {
+    shutdown_chan: Sender<()>,
+    shutdown_mutex: Arc<Mutex<()>>,
+}
+
+impl WebServer {
+    pub fn run(addr: std::net::SocketAddr) -> WebServer {
+        // todo: not have the damn js inline in the func
+        const JS: &'static str = r#"
+var sock = new WebSocket("ws://" + window.location.host + "/ws");
+sock.onmessage = function (e) {
+    console.log(e);
+}
+sock.onopen = function (e) {
+    sock.send("Hello!");
+}"#;
+        let (shutdown_tx, shutdown_rx) = channel::<()>();
+
+        let shutdown_mutex = Arc::new(Mutex::new(()));
+        let thread_shutdown_mutex = Arc::clone(&shutdown_mutex);
+        thread::spawn(move || {
+            // N.B! Despite the fact we never use the value inside the mutex (it's () after all..) we need to bind
+            // it to a variable so that it lives until the end of the thread, else it would unlock immediately.
+            let _lock = thread_shutdown_mutex.lock().unwrap();
+
+            let websocket = warp::path("ws").and(warp::ws2()).map(|ws: warp::ws::Ws2| {
+                ws.on_upgrade(|websocket| {
+                    let (tx, rx) = websocket.split();
+                    //stream::once::<Message, _>(Ok(Message::text("Hello")))
+                    rx.forward(tx).map(|_| ()).map_err(|e| {
+                        log::error!("Websocket error: {}", e);
+                    })
+                })
+            });
+            let script = warp::path("script.js").map(|| JS);
+            let home = warp::path::end().map(|| warp::reply::html(build_template().to_string()));
+            let routes = warp::get2().and(websocket.or(script).or(home));
+
+            let (_addr, server) =
+                warp::serve(routes).bind_with_graceful_shutdown(addr, shutdown_rx);
+            tokio::run(server);
+        });
+        WebServer {
+            shutdown_chan: shutdown_tx,
+            shutdown_mutex,
+        }
+    }
+
+    pub fn shutdown(self) {
+        log::debug!("Web server shutting down...");
+        self.shutdown_chan.send(()).unwrap();
+        let _lock = self.shutdown_mutex.lock().unwrap();
+        log::info!("Web server shutdown");
+    }
+}