From 996822b04634f75690d6f5874355026b69701a87 Mon Sep 17 00:00:00 2001
From: Zutatensuppe <oo.para@gmail.com>
Date: Fri, 4 Dec 2020 00:04:47 +0100
Subject: [PATCH] persist games in fixed intervals and on shutdown

---
 common/Util.js            | 14 +++++++
 scripts/server            |  2 +-
 server/Game.js            | 17 ++++----
 server/WebSocketServer.js |  4 ++
 server/index.js           | 87 ++++++++++++++++++++++++++-------------
 5 files changed, 88 insertions(+), 36 deletions(-)

diff --git a/common/Util.js b/common/Util.js
index 1ed3bd4..5980f4c 100644
--- a/common/Util.js
+++ b/common/Util.js
@@ -7,6 +7,19 @@ export const randomInt = (min, max) => Math.floor(Math.random() * (max - min + 1
 // get one random item from the given array
 export const choice = (array) => array[randomInt(0, array.length - 1)]
 
+export const throttle = (fn, delay) => {
+  let canCall = true
+  return (...args) => {
+    if (canCall) {
+      fn.apply(null, args)
+      canCall = false
+      setTimeout(() => {
+        canCall = true
+      }, delay)
+    }
+  }
+}
+
 // return a shuffled (shallow) copy of the given array
 export const shuffle = (array) => {
   let arr = array.slice()
@@ -37,6 +50,7 @@ export default {
   uniqId,
   randomInt,
   choice,
+  throttle,
   shuffle,
   timestamp,
 }
diff --git a/scripts/server b/scripts/server
index 5b5dbf4..3bff09c 100755
--- a/scripts/server
+++ b/scripts/server
@@ -2,4 +2,4 @@
 
 cd "$RUN_DIR/server"
 
-nodemon -d 2 index.js
+nodemon index.js
diff --git a/server/Game.js b/server/Game.js
index 3256b3f..8d14e87 100644
--- a/server/Game.js
+++ b/server/Game.js
@@ -30,18 +30,21 @@ function loadAllGames() {
   }
 }
 
-function store(gameId) {
-  const game = GameCommon.get(gameId)
-  fs.writeFileSync('./../data/' + gameId + '.json', JSON.stringify({
-    puzzle: game.puzzle,
-    players: game.players,
-  }))
+function persistAll() {
+  const games = GameCommon.getAllGames()
+  for (const gameId of Object.keys(games)) {
+    const game = games[gameId]
+    fs.writeFileSync('./../data/' + gameId + '.json', JSON.stringify({
+      puzzle: game.puzzle,
+      players: game.players,
+    }))
+  }
 }
 
 export default {
   loadAllGames,
   getAllGames: GameCommon.getAllGames,
-  store,
+  persistAll,
   createGame,
   exists: GameCommon.exists,
   addPlayer: GameCommon.addPlayer,
diff --git a/server/WebSocketServer.js b/server/WebSocketServer.js
index 96d93d9..68fbe0e 100644
--- a/server/WebSocketServer.js
+++ b/server/WebSocketServer.js
@@ -61,6 +61,10 @@ class WebSocketServer {
     })
   }
 
+  close() {
+    this._websocketserver.close()
+  }
+
   notifyOne(data, socket) {
     socket.send(JSON.stringify(data))
   }
diff --git a/server/index.js b/server/index.js
index 9be1bfe..acca305 100644
--- a/server/index.js
+++ b/server/index.js
@@ -109,30 +109,6 @@ wss.on('close', async ({socket}) => {
   }
 })
 
-const ensurePlayerGame = (gameId, clientId, socket) => {
-  Game.addPlayer(gameId, clientId)
-  Game.addSocket(gameId, socket)
-  Game.store(gameId)
-  const game = Game.get(gameId)
-  notify(
-    [Protocol.EV_SERVER_INIT, {
-      puzzle: game.puzzle,
-      players: game.players,
-      evtInfos: game.evtInfos,
-    }],
-    [socket]
-  )
-}
-
-const handlePlayerInput = (gameId, clientId, clientSeq, clientEvtData) => {
-  const changes = Game.handleInput(gameId, clientId, clientEvtData)
-  Game.store(gameId)
-  notify(
-    [Protocol.EV_SERVER_EVENT, clientId, clientSeq, changes],
-    Game.getSockets(gameId)
-  )
-}
-
 wss.on('message', async ({socket, data}) => {
   try {
     const proto = socket.protocol.split('|')
@@ -145,14 +121,39 @@ wss.on('message', async ({socket, data}) => {
         if (!Game.exists(gameId)) {
           throw `[game ${gameId} does not exist... ]`
         }
-        ensurePlayerGame(gameId, clientId, socket)
+        Game.addPlayer(gameId, clientId)
+        Game.addSocket(gameId, socket)
+        const game = Game.get(gameId)
+        notify(
+          [Protocol.EV_SERVER_INIT, {
+            puzzle: game.puzzle,
+            players: game.players,
+            evtInfos: game.evtInfos,
+          }],
+          [socket]
+        )
       } break;
 
       case Protocol.EV_CLIENT_EVENT: {
         const clientSeq = msg[1]
         const clientEvtData = msg[2]
-        ensurePlayerGame(gameId, clientId, socket)
-        handlePlayerInput(gameId, clientId, clientSeq, clientEvtData)
+        Game.addPlayer(gameId, clientId)
+        Game.addSocket(gameId, socket)
+
+        const game = Game.get(gameId)
+        notify(
+          [Protocol.EV_SERVER_INIT, {
+            puzzle: game.puzzle,
+            players: game.players,
+            evtInfos: game.evtInfos,
+          }],
+          [socket]
+        )
+        const changes = Game.handleInput(gameId, clientId, clientEvtData)
+        notify(
+          [Protocol.EV_SERVER_EVENT, clientId, clientSeq, changes],
+          Game.getSockets(gameId)
+        )
       } break;
     }
   } catch (e) {
@@ -161,5 +162,35 @@ wss.on('message', async ({socket, data}) => {
 })
 
 Game.loadAllGames()
-app.listen(port, hostname, () => console.log(`server running on http://${hostname}:${port}`))
+const server = app.listen(
+  port,
+  hostname,
+  () => console.log(`server running on http://${hostname}:${port}`)
+)
 wss.listen()
+
+// persist games in fixed interval
+setInterval(() => {
+  console.log('Persisting games...');
+  Game.persistAll()
+}, config.persistence.interval)
+
+const gracefulShutdown = (signal) => {
+  console.log(`${signal} received...`)
+  Game.persistAll()
+  server.close()
+  wss.close()
+}
+
+// used by nodemon
+process.once('SIGUSR2', function () {
+  gracefulShutdown('SIGUSR2')
+});
+
+process.once('SIGINT', function (code) {
+  gracefulShutdown('SIGINT')
+});
+
+process.once('SIGTERM', function (code) {
+  gracefulShutdown('SIGTERM')
+});