update

README.md

@@ -44,9 +44,7 @@ Prepend `publicaddr` wrapper to your `node` binary (or other interpreter like `t
 
 And [prebuild/prebuildify](https://github.com/prebuild/prebuildify) [prebuild/prebuildify-cross](https://github.com/prebuild/prebuildify-cross) [prebuild/node-gyp-build](https://github.com/prebuild/node-gyp-build/blob/master/node-gyp-build.js), they made shipping multiarch prebuilt native modules incredibly simple.
 
-## Demo
-
-### Simple usage
+## Demo: Rolling update between 2 versions without downtime
 
 Clone [this repo](https://github.com/jokester/publicaddr) and run multiple instances like:
 
@@ -55,22 +53,19 @@ git clone https://github.com/jokester/publicaddr
 
 cd publicaddr/demo
 
-npm install
+# run version a with 4 containers
+docker-compose up -d
 
-npm start &
-npm start &
-npm start &
-npm start &
+# start a HTTP benchmark
+wrk -t6 -c2000 -d120s http://127.0.0.1:3000 &
 
-wrk -t6 -c2000 -d10s http://127.0.0.1:3000 # or other HTTP benchmark tool
+# switch between version a / b, for a few times
+./switch-version.sh a b a b
 
-kill %1 %2 %3 %4
+# after benchmark ends
+docker-compose down
 ```
 
-### Inside containers
-
-Clone [this repo](https://github.com/jokester/publicaddr) and run `docker-compose up` in `demo/`
-
 ## License
 
 BSD

demo/demo-server.mjs

@@ -5,20 +5,34 @@ const waitRandom = (min, max) => wait(min + Math.random() * (max - min))
 const processTag = `demo-server-version-${process.env.VERSION ?? '?'}-${Math.random().toString(16).slice(2, 10)}`
 
 let reqCount = 0
+let onFlight = 0
 
 const server = http.createServer(async (req, res) => {
-    res.writeHead(200);
+    ++onFlight;
+    res.writeHead(200, undefined, { connection: 'Close' });
     await waitRandom(20, 100);
     res.end(`reqCount: ${++reqCount} from ${processTag}`)
+    --onFlight;
 })
 
+function log(...args) {
+    console.info(`${Date.now().toFixed(2)} ${processTag}:`, ...args)
+}
+
+async function waitRequestsEnd() {
+    while (onFlight > 0) {
+        await wait(1e3)
+    }
+}
+
 function startReportCount() {
     let lastReqCountReported = 0
     const interval = 10 // s
     const timer = setInterval(() => {
         const delta = reqCount - lastReqCountReported
         lastReqCountReported = reqCount
-        console.info(`PID ${process.pid} / ${processTag}: reqCount: ${reqCount} / delta: ${delta} in last ${interval}s`)
+        log(`reqCount: ${reqCount}`);
+        log(`mean RPS: ${(delta / interval).toFixed(2)}`);
     }, interval * 1e3)
     return () => clearInterval(timer)
 }
@@ -32,14 +46,15 @@ async function main() {
     const stopReportCount = startReportCount()
 
     server.listen(port, () => {
-        console.info(`PID ${process.pid} / ${processTag}: listening on port ${port}`)
+        log(`listening on port ${port}`)
     })
     await gotSignal
-    await new Promise(f => server.close(f))
+    const error = await new Promise(f => server.close(f))
+    if (error) {
+        console.error('server close error:', error)
+    }
     stopReportCount()
-    console.info(`PID ${process.pid} / ${processTag}: app closing. pretend to be cleaning up...`)
-    await wait(10e3);
-    console.info(`PID ${process.pid} / ${processTag}: app closed.`)
+    log(`app closing.`)
 }
 
 await main();

demo/docker-compose.yaml

@@ -14,7 +14,7 @@ services:
     environment:
       VERSION: 'a'
     deploy:
-      replicas: ${VERSION_A_REPLICA:-0}
+      replicas: ${VERSION_A_REPLICA:-4}
 
   demo-server-b: &demo-server
     build: .