Fixed dead worker issue

lib/sticky-session.js

@@ -71,8 +71,19 @@ function layer4HashBalancedConnectionListener(c) {
  var worker,
  random = crypto.randomBytes(4).readUInt32BE(0, true);
 
+ var maxRetries = 15,
+ triesNumber = 0;
+
  // Pass connection to worker
- worker = self.workers[random % self.workers.length];
+ do {
+ worker = self.workers[random % self.workers.length];
+ triesNumber++;
+ } while(worker.isDead() && triesNumber < maxRetries);
+
+ if (triesNumber >= maxRetries) {
+ console.error('Worker not found: all workers are dead');
+ }
+
  worker.send('sticky-session:sync', c);
 }
 
@@ -86,15 +97,37 @@ function patchConnection(c, fd, agent) {
 
  // Pass connection to worker
  worker = agent.workers[ipHash % agent.workers.length];
- worker.send({ cmd: 'sticky-session:connection', data: c.data }, fd);
+
+ worker.send({
+ cmd: 'sticky-session:connection', 
+ data: c.data 
+ }, fd);
+}
+
+/**
+ * Handle sending messages to dead worker
+ */
+function patchWorker(worker) {
+ worker.send = (function(original) {
+ return function(message, socket) {
+ if (this.isDead()) {
+ socket.write('Error: worker has been died');
+ socket.end();
+
+ return;
+ }
+
+ original.apply(this, arguments);
+ };
+ })(worker.send);
+
+ return worker;
 }
 
 function sticky(options, callback) {
- var connectionListener,
- num = 0,
- agent = new StickyAgent(options, callback);
+ var agent = new StickyAgent(options, callback);
 
- if(cluster.isMaster) {
+ if (cluster.isMaster) {
  return agent.setupMaster();
  } else {
  return agent.setupSlave();
@@ -171,30 +204,63 @@ function StickyAgent(options, callback) {
 StickyAgent.prototype.setupMaster = function() {
  var self = this;
 
+ cluster.on('exit', (worker, code, signal) => {
+ if (signal) {
+ console.log(`sticky-session: worker was killed by signal: ${signal}`);
+ } 
+
+ if (code !== 0) {
+ console.log(`sticky-session: worker exited with error code: ${code}`);
+ }
+
+ if (worker.exitedAfterDisconnect === true) {
+ console.log('sticky-session: worker exited after disconnect');
+ }
+
+ console.log('sticky-session: worker died!');
+
+ });
+
  // Master will spawn `num` workers
  self.workers = [];
  for (var i = 0; i < self.num; i++) {
  !function spawn(i) {
- self.workers[i] = cluster.fork();
- // Restart worker on exit
- self.workers[i].on('exit', function() {
- console.error('sticky-session: worker died');
- spawn(i);
- });
-
- self.workers[i].on('message', function(msg, c) {
- if (typeof msg === 'object')
- {
- if (msg.cmd === 'sticky-session:ack') {
- patchConnection(msg, c, self);
- }
+ var worker = patchWorker(cluster.fork());
+
+ // Restart worker on exit
+ worker.on('exit', function(code, signal) {
+ if (signal) {
+ console.log(`sticky-session: worker was killed by signal: ${signal}`);
+ } 
+
+ if (code !== 0) {
+ console.log(`sticky-session: worker exited with error code: ${code}`);
  }
+
+ console.log('sticky-session: worker died!');
+ spawn(i);
  });
 
+ worker.on('uncaughtException', function(err) {
+ console.log(`stick-session: uncaught exception: ${err}`);
+ });
+
+ worker.on('error', function() {
+ console.error('sticky-session: worker error', arguments);
+ });
+
+ worker.on('message', function(msg, c) {
+ if (typeof msg === 'object' && msg.cmd === 'sticky-session:ack') {
+ patchConnection(msg, c, self);
+ }
+ });
+
+ self.workers[i] = worker;
  }(i);
  }
 
  self.seed = crypto.randomBytes(4).readUInt32BE(0, true) % 0x80000000;
+
  return net.createServer(self.serverOptions, function(c) {
  self.connectionListener(c);
  });
@@ -207,8 +273,9 @@ StickyAgent.prototype.setupSlave = function() {
  self.callback;
 
  process.on('message', function(msg, socket) {
-
- if( socket ) self.listener(msg, socket);
+ if (socket) { 
+ self.listener(msg, socket);
+ }
  });
 
  if (!self.server) {
@@ -243,25 +310,29 @@ StickyAgent.prototype.listener = function(msg, socket) {
  * Reading data once from file descriptor and extract ip from the
  * header.
  */
- if (socket)
- {
+ if (socket) {
  socket.once('data', function(data) {
  var strData = data.toString().toLowerCase(),
  searchPos = strData.indexOf(self.header),
  endPos;
 
- if( self.serverOptions.pauseOnConnect )
+ if (self.serverOptions.pauseOnConnect) {
  socket.pause();
+ }
 
  /**
  * If the header was not found return, probably unwanted behavior.
  */
  if (searchPos === -1) {
  if (self.ignoreMissingHeader) {
- process.send(
- { cmd: 'sticky-session:ack', realIP: socket.remoteAddress, data: data },
+ process.send({ 
+ cmd: 'sticky-session:ack', 
+ realIP: socket.remoteAddress, 
+ data: data 
+ },
  socket
  );
+
  return;
  } else {
  socket.destroy();
@@ -275,15 +346,18 @@ StickyAgent.prototype.listener = function(msg, socket) {
  strData = strData.substr(searchPos, endPos - searchPos - 1).trim();
 
  //Send ackknownledge + data and real ip adress back to master
- process.send(
- { cmd: 'sticky-session:ack', realIP: strData, data: data },
+ process.send({ 
+ cmd: 'sticky-session:ack', 
+ realIP: strData, 
+ data: data 
+ },
  socket
  );
-
  });
 
- if( self.serverOptions.pauseOnConnect )
+ if (self.serverOptions.pauseOnConnect) {
  socket.resume();
+ }
  }
  }
  /**