Merge branch 'features/maintain-worker-count'

examples/reload.js

@@ -8,7 +8,7 @@ var cluster = require('../')
 
 // try loading, and changing "Hello", to "Hello World"
 
-var body = 'Hello'
+var body = 'Hello World'
   , len = body.length;
 var server = http.createServer(function(req, res){
   res.writeHead(200, { 'Content-Length': len });

lib/master.js

@@ -48,7 +48,8 @@ var node = process.execPath
  *   - 'working directory`  Working directory defaulting to the script's dir
  *   - 'backlog` Connection backlog, defaulting to 128
  *   - 'socket path` Master socket path defaulting to `./`
- *   - 'timeout` Worker shutdown timeout in milliseconds, defaulting to 60000
+ *   - 'timeout` Worker shutdown timeout in milliseconds, defaulting to 60,000
+ *   - 'ping interval` Interval at which master pings workers, defaulting to 10,000
  *   - 'user` User id / name
  *   - 'group` Group id / name
  *
@@ -95,6 +96,7 @@ var Master = module.exports = function Master(server) {
       'backlog': 128
     , 'working directory': this.dir
     , 'socket path': this.dir
+    , 'ping interval': 10000
     , 'timeout': 60000
   };
 
@@ -127,6 +129,9 @@ var Master = module.exports = function Master(server) {
     sock.setEncoding('ascii');
     sock.on('data', self.frame.bind(self));
   });
+
+  // maintain worker count
+  this.on('listening', this.maintainWorkerCount.bind(this));
 };
 
 /**
@@ -177,8 +182,7 @@ Master.prototype.__defineGetter__('socketPath', function(){
 
 Master.prototype.__defineGetter__('environmentMatches', function(){
   if (this._env) 
-    return this.env == this._env
-      || 'all' == this._env;
+    return this.env == this._env || 'all' == this._env;
   return true;
 });
 
@@ -367,6 +371,24 @@ Master.prototype.start = function(){
   });
 };
 
+/**
+ * Maintain worker count, re-spawning if necessary.
+ *
+ * @api private
+ */
+
+Master.prototype.maintainWorkerCount = function(){
+  // check workers
+  this.children.forEach(function(worker){
+    var pid = worker.proc.pid;
+    if (!pid) this.spawnWorker(worker.id);
+  }, this);
+
+  // check again
+  setTimeout(this.maintainWorkerCount.bind(this)
+    , this.options['ping interval']);
+};
+
 /**
  * Spawn `n` workers.
  *