Convert to JS.

.gitignore

@@ -1,5 +1,4 @@
 /node_modules
 *~
 /examples/node_modules
-/build
-npm-debug.log
+npm-debug.log

ChangeLog

@@ -1,3 +1,7 @@
+0.3.0 -
+  * full JS implementation, removed c code & bindings
+  * example bugfixes
+
 0.2.3 -
   * node.js 0.10.0 support - uprade to latest bindings and include in .travis.yml
 

examples/package.json

@@ -4,6 +4,6 @@
   "description": "dependencies required by the toobusy examples",
   "private": true,
   "dependencies": {
-    "express": "2"
+    "express": "3"
   }
 }

examples/standalone.js

@@ -1,14 +1,14 @@
 // first, we want to be able to get cpu usage stats in terms of percentage
 var loaded = false;
-var toobusy = require('../');
+var toobusy = require('..');
 
 var work = 524288;
 
 function worky() {
   var howBusy = toobusy();
   if (howBusy) {
     work /= 4;
-    console.log("I can't work! I'm too busy:", howBusy + "ms behind");
+    console.log("I can't work! I'm too busy:", toobusy.lag() + "ms behind");
   }
   work *= 2;
   for (var i = 0; i < work;) i++;

index.js

@@ -1,5 +1 @@
-var bindings = require('bindings')('toobusy.node')
-module.exports = bindings.toobusy;
-module.exports.shutdown = bindings.shutdown;
-module.exports.maxLag = bindings.maxLag;
-module.exports.lag = bindings.lag;
+module.exports = require('./toobusy');

package.json

@@ -2,9 +2,8 @@
   "name": "toobusy",
   "description": "Don't fall over when your Node.JS server is too busy.",
   "homepage": "https://github.com/lloyd/node-toobusy",
-  "version": "0.2.2",
+  "version": "0.3.0",
   "dependencies": {
-    "bindings": "1.1.0"
   },
   "devDependencies": {
     "should": "1.2.1",
@@ -32,7 +31,7 @@
   ],
   "main": "./index.js",
   "engines": {
-    "node": ">=0.8.0"
+    "node": ">=0.9.1"
   },
   "scripts": {
     "test": "mocha tests"

toobusy.js

@@ -0,0 +1,54 @@
+var STANDARD_HIGHWATER = 70;
+var STANDARD_INTERVAL = 500;
+
+// A dampening factor.  When determining average calls per second or
+// current lag, we weigh the current value against the previous value 2:1
+// to smooth spikes.
+var AVG_DECAY_FACTOR = 3;
+
+var lastTime = new Date().valueOf(), now, lag, highWater = STANDARD_HIGHWATER, interval = STANDARD_INTERVAL, currentLag = 0;
+
+var checkInterval = setInterval(function(){
+  now = new Date().valueOf();
+  lag = now - lastTime;
+  lag = (lag < interval) ? 0 : lag - interval;
+  currentLag = (lag + (currentLag * (AVG_DECAY_FACTOR - 1))) / AVG_DECAY_FACTOR;
+  lastTime = now;
+}, interval);
+
+// Don't keep process open just for this timer.
+checkInterval.unref();
+
+var toobusy = function(){
+  // If current lag is < 2x the highwater mark, we don't always call it 'too busy'. E.g. with a 50ms lag
+  // and a 40ms highWater (1.25x highWater), 25% of the time we will block. With 80ms lag and a 40ms highWater,
+  // we will always block.
+  var pctToBlock = (currentLag - highWater) / highWater;
+  var rand = Math.random();
+  return rand < pctToBlock;
+};
+
+toobusy.lag = function(){
+  return parseInt(currentLag, 10);
+};
+
+toobusy.maxLag = function(newLag){
+  if(!newLag) return highWater;
+
+  // If an arg was passed, try to set highWater.
+  if(Object.prototype.toString.call(newLag) !== "[object Number]"){
+    throw "Expected numeric first argument.";
+  }
+  newLag = parseInt(newLag, 10);
+  if(newLag < 10){
+    throw "Maximum lag should be greater than 10ms.";
+  }
+  highWater = newLag;
+  return highWater;
+};
+
+toobusy.shutdown = function(){
+  clearInterval(checkInterval);
+};
+
+module.exports = toobusy;