[Fixes josdejong#58] Allocate Debug ports safely, so multiple pools d…

…on’t accidentally overlap

lib/Pool.js

@@ -1,7 +1,8 @@
 var Promise = require('./Promise');
 var WorkerHandler = require('./WorkerHandler');
 var environment = require('./environment');
-
+var DebugPortAllocator = require('./debug-port-allocator');
+var DEBUG_PORT_ALLOCATOR = new DebugPortAllocator();
 /**
  * A pool to manage workers
  * @param {String} [script]   Optional worker script
@@ -24,7 +25,7 @@ function Pool(script, options) {
 
   this.forkArgs = options.forkArgs || [];
   this.forkOpts = options.forkOpts || {};
-  this.debugPortStart = options.debugPortStart || 43210;
+  this.debugPortStart = (options.debugPortStart || 43210);
   this.nodeWorker = options.nodeWorker;
 
   // configuration
@@ -243,7 +244,7 @@ Pool.prototype._getWorker = function() {
     worker = new WorkerHandler(this.script, {
       forkArgs: this.forkArgs,
       forkOpts: this.forkOpts,
-      debugPort: this.debugPortStart + workers.length,
+      debugPort: DEBUG_PORT_ALLOCATOR.nextAvailableStartingAt(this.debugPortStart),
       nodeWorker: this.nodeWorker
     });
     workers.push(worker);
@@ -260,6 +261,7 @@ Pool.prototype._getWorker = function() {
  * @protected
  */
 Pool.prototype._removeWorker = function(worker) {
+  DEBUG_PORT_ALLOCATOR.releasePort(worker.debugPort)
   // terminate the worker (if not already terminated)
   worker.terminate();
   this._removeWorkerFromList(worker);
@@ -343,7 +345,7 @@ Pool.prototype._ensureMinWorkers = function() {
       this.workers.push(new WorkerHandler(this.script, {
         forkArgs: this.forkArgs,
         forkOpts: this.forkOpts,
-        debugPort: this.debugPortStart + i
+        debugPort: DEBUG_PORT_ALLOCATOR.nextAvailableStartingAt(this.debugPortStart)
       }));
     }
   }

lib/WorkerHandler.js

@@ -152,6 +152,7 @@ function objectToError (obj) {
 function WorkerHandler(script, _options) {
   this.script = script || getDefaultWorker();
   var options = _options || {};
+  this.debugPort = options.debugPort;
 
   if (environment.platform == 'browser') {
     // check whether Worker is supported by the browser

lib/debug-port-allocator.js

@@ -0,0 +1,28 @@
+'use strict';
+
+var MAX_PORTS = 65535;
+module.exports = DebugPortAllocator;
+function DebugPortAllocator() {
+  this.ports = Object.create(null);
+  this.length = 0;
+}
+
+DebugPortAllocator.prototype.nextAvailableStartingAt = function(starting) {
+  while (this.ports[starting] === true) {
+    starting++;
+  }
+
+  if (starting >= MAX_PORTS) {
+    throw new Error('WorkerPool debug port limit reached: ' + starting + '>= ' + MAX_PORTS );
+  }
+
+  this.ports[starting] = true;
+  this.length++;
+  return starting;
+};
+
+DebugPortAllocator.prototype.releasePort = function(port) {
+  delete this.ports[port];
+  this.length--;
+};
+

package.json

@@ -34,6 +34,8 @@
     "webpack": "^1.13.1"
   },
   "dependencies": {
-    "object-assign": "4.1.1"
+    "@babel/core": "^7.3.4",
+    "object-assign": "4.1.1",
+    "rsvp": "^4.8.4"
   }
 }

test/debug-port-allocator-test.js

@@ -0,0 +1,39 @@
+'use strict';
+
+var assert = require('assert');
+var DebugPortAllocator = require('../lib/debug-port-allocator');
+
+describe('DebugPortAllocator', function () {
+  it('works', function() {
+    var allocator = new DebugPortAllocator();
+    assert.equal(allocator.length, 0);
+    assert.equal(allocator.nextAvailableStartingAt(5), 5);
+    assert.equal(allocator.length, 1);
+    assert.equal(allocator.nextAvailableStartingAt(5), 6);
+    assert.equal(allocator.length, 2);
+    assert.equal(allocator.nextAvailableStartingAt(5), 7);
+    assert.equal(allocator.length, 3);
+    assert.equal(allocator.nextAvailableStartingAt(4), 4);
+    assert.equal(allocator.length, 4);
+    assert.equal(allocator.nextAvailableStartingAt(4), 8);
+    assert.equal(allocator.length, 5);
+
+    allocator.releasePort(8);
+    assert.equal(allocator.length, 4);
+    assert.equal(allocator.nextAvailableStartingAt(8), 8);
+    allocator.releasePort(8);
+    allocator.releasePort(7);
+    allocator.releasePort(6);
+    allocator.releasePort(5);
+    allocator.releasePort(4);
+    assert.equal(allocator.length, 0);
+
+    assert.throws(function() {
+      allocator.nextAvailableStartingAt(65535);
+    }, /WorkerPool debug port limit reached/);
+    assert.throws(function() {
+      allocator.nextAvailableStartingAt(75535);
+    }, /WorkerPool debug port limit reached/);
+  })
+});
+