entirely rewrite all (carcinization)

.gitignore

@@ -1,2 +1,6 @@
 node_modules
 db.level
+
+# Added by cargo
+
+/target

Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "incdec"
+version = "0.1.0"
+authors = ["osmarks <osmarks@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+lazy_static = "1.4"
+tide = { version = "0.16.0", default-features = false, features = ["h1-server"] }
+async-std = { version = "1.9.0", features = ["attributes", "unstable"], default-features = false }
+tide-websockets = "0.2"
+anyhow = "1.0"
+prometheus = { version = "0.11.0", features = ["process"] }
+memchr = "2"

incdec.js

@@ -35,10 +35,7 @@ app.get("/", (req, res) => {
     res.sendFile(__dirname + "/index.html")
 })
 
-const sendCounter = (ws, x) => ws.send(JSON.stringify({
-    type: "value",
-    value: x
-}))
+const sendCounter = (ws, x) => ws.send(x.toString())
 
 const transmitCounterUpdate = _.throttle(newValue => {
     wss.getWss().clients.forEach(ws => sendCounter(ws, newValue))
@@ -48,11 +45,10 @@ app.ws("/api", (ws, req) => {
     console.log("Connected")
     sendCounter(ws, counter)
     ws.on("message", async data => {
-        const msg = JSON.parse(data)
-        if (msg.type === "increment") {
+        if (data.includes("i")) {
             counter++
             transmitCounterUpdate(counter)
-        } else if (msg.type === "decrement") {
+        } else if (data.includes("d")) {
             counter--
             transmitCounterUpdate(counter)
         }

incdec.txt

@@ -0,0 +1 @@
+30

index.html

@@ -1,3 +1,6 @@
+<title>IncDec</title>
+<meta name="description" content="IncDec - the thrilling game of incrementing and decrementing.">
+<meta charset="utf-8">
 <meta name="viewport" content="user-scalable=0"> 
 <noscript>JavaScript is required for this.</noscript>
 <style>
@@ -35,9 +38,9 @@
     }
 </style>
 <div id="container">
-    <button id="up" onclick="increment()">+</button>
-    <div id="value">Loading...</div>
     <button id="down" onclick="decrement()">-</button>
+    <div id="value">Loading...</div>
+    <button id="up" onclick="increment()">+</button>
 </div>
 <script>
     var output = document.querySelector("#value")
@@ -54,26 +57,23 @@
         output.innerText = text
     }
 
-    function send(obj) {
-        socket.send(JSON.stringify(obj))
+    function send(s) {
+        socket.send(s)
     }
 
     socket.onmessage = function(ev) {
-        var msg = JSON.parse(ev.data)
-        if (msg.type === "value") {
-            display(msg.value.toString())
-        }
+        display(ev.data)
     }
 
     function increment() {
-        send({
-            type: "increment"
-        })
+        send("inc")
     }
 
     function decrement() {
-        send({
-            type: "decrement"
-        })
+        send("dec")
+    }
+
+    socket.onclose = function(ev) {
+        display("Disconnected!")
     }
 </script>

runner.js

@@ -0,0 +1,3 @@
+const ws = require("ws")
+const a = new ws("https://osmarks.net/incdec/api")
+a.onopen = () => setInterval(() => a.send("i"), 1)

src/main.rs

@@ -0,0 +1,124 @@
+use std::env;
+use tide_websockets::{WebSocket, Message};
+use prometheus::{TextEncoder, Encoder, register_int_counter, IntCounter, register_int_gauge, IntGauge};
+use anyhow::Result;
+use tide::Body;
+use std::sync::{atomic::{AtomicI64, Ordering}, Arc};
+use tide_websockets::WebSocketConnection;
+use async_std::prelude::*;
+use memchr::memchr;
+use std::time::Duration;
+use async_std::task;
+use async_std::fs::{read_to_string, write};
+use lazy_static::lazy_static;
+
+lazy_static! {
+    static ref OPS_COUNTER: IntCounter = register_int_counter!("incdec_ops", "IncDec operations executed").unwrap();
+    static ref COUNTER_GAUGE: IntGauge = register_int_gauge!("incdec_counter", "Current counter value").unwrap();
+    static ref CONNECTIONS_COUNTER: IntCounter = register_int_counter!("incdec_total_conns", "Total client connections made").unwrap();
+}
+
+fn set_mime_str(s: &'static str, mime: &'static str) -> Body {
+    let mut b: Body = s.into();
+    b.set_mime(mime);
+    b
+}
+
+type Counter = Arc<AtomicI64>;
+
+fn update_counter(ctr: &Counter, by: i64) -> i64 {
+    let new_val = ctr.fetch_add(by, Ordering::Relaxed);
+    OPS_COUNTER.inc();
+    COUNTER_GAUGE.set(new_val);
+    new_val
+}
+
+async fn handle_connection(ws: WebSocketConnection, ctr: Counter) -> Result<()> {
+    CONNECTIONS_COUNTER.inc();
+    let mut counter_val = ctr.load(Ordering::Relaxed);
+    ws.send_string(format!("{}", counter_val)).await?;
+    let ctr_ = ctr.clone();
+    let mut ws_ = ws.clone();
+    let ws_link = async move {
+        while let Some(Ok(Message::Text(txt))) = ws_.next().await {
+            if let Some(_) = memchr(b'i', txt.as_bytes()) {
+                // increment
+                update_counter(&ctr_, 1);
+            }
+            else if let Some(_) = memchr(b'd', txt.as_bytes()) {
+                // decrement
+                update_counter(&ctr_, -1);
+            }
+        }
+        let r: Result<()> = Ok(());
+        r
+    };
+    let poll_value = async move {
+        loop {
+            task::sleep(Duration::from_millis(50)).await;
+            let new = ctr.load(Ordering::Relaxed);
+            if counter_val != new {
+                ws.send_string(format!("{}", new)).await?;
+                counter_val = new;
+            }
+        }
+    };
+    ws_link.race(poll_value).await?;
+    Ok(())
+}
+
+#[async_std::main]
+async fn main() -> Result<()> {
+    let args: Vec<String> = env::args().collect();
+    let save_path = args[1].clone();
+    let port = args[2].parse::<u16>()?;
+
+    let counter = Arc::new(AtomicI64::new({
+        match read_to_string(&save_path).await {
+            Ok(s) => s.parse::<i64>()?,
+            Err(_) => 0
+        }
+    }));
+    let counter_ = counter.clone();
+
+    let mut app = tide::with_state(counter);
+    app.at("/api").get(WebSocket::new(|req: tide::Request<Counter>, stream| {
+        let state = req.state().clone();
+        async move { 
+            handle_connection(stream, state).await.map_err(|_| tide::Error::from_str(tide::StatusCode::InternalServerError, "should not occur"))
+        }
+    }));
+    app.at("/metrics").get(|_req| async {
+        let mut buffer = Vec::new();
+        let encoder = TextEncoder::new();
+        let metric_families = prometheus::gather();
+        encoder.encode(&metric_families, &mut buffer)?;
+        let mut b = Body::from_bytes(buffer);
+        b.set_mime("text/plain");
+        Ok(b)
+    });
+    app.at("/inc").post(|req: tide::Request<Counter>| async move {
+        let mut b: Body = update_counter(req.state(), 1).to_string().into();
+        b.set_mime("text/plain");
+        Ok(b)
+    });
+    app.at("/dec").post(|req: tide::Request<Counter>| async move {
+        let mut b: Body = update_counter(req.state(), -1).to_string().into();
+        b.set_mime("text/plain");
+        Ok(b)
+    });
+    app.at("/").get(|_req| async { Ok(set_mime_str(include_str!("../index.html"), "text/html")) });
+
+    println!("Running on port {}", port);
+
+    task::spawn(async move {
+        loop {
+            write(&save_path, format!("{}", counter_.load(Ordering::Relaxed))).await.unwrap();
+            task::sleep(Duration::from_secs(10)).await;
+        }
+    });
+
+    app.listen(("0.0.0.0", port)).await?;
+
+    Ok(())
+}