toobusy-js - npm Package Compare versions

Comparing version 0.3.1 to 0.4.0

package.json

@@ -5,8 +5,8 @@ {
   "homepage": "https://github.com/STRML/node-toobusy",
-  "version": "0.3.1",
-  "dependencies": {
-  },
+  "version": "0.4.0",
+  "dependencies": {},
   "devDependencies": {
-    "should": "1.2.1",
-    "mocha": "1.7.0"
+    "mocha": "1.7.0",
+    "pre-commit": "^1.0.5",
+    "should": "1.2.1"
   },
@@ -13,0 +13,0 @@ "maintainers": [

README.md

@@ -43,5 +43,5 @@ # Is Your Node Process Too Busy?
     express = require('express');
-    
+
 var app = express();
-    
+
 // middleware which blocks requests when we're too busy
@@ -53,5 +53,5 @@ app.use(function(req, res, next) {
     next();
-  } 
+  }
 });
-    
+
 app.get('/', function(req, res) {
@@ -63,5 +63,5 @@ // processing the request requires some work!
 });
-  
+
 var server = app.listen(3000);
-  
+
 process.on('SIGINT', function() {
@@ -83,3 +83,4 @@ server.close();
 // set maximum lag to an aggressive value
-require('toobusy-js').maxLag(10);
+var toobusy = require('toobusy-js');
+toobusy.maxLag(10);
 ```
@@ -86,0 +87,0 @@

tests.js

@@ -1,11 +0,14 @@
-const
-should = require('should'),
-toobusy = require('./');
+'use strict';
+var should = require('should');
+var toobusy = require('./');
 
+/*global describe, it, beforeEach, afterEach */
 describe('the library', function() {
-  it('should export a couple functions', function(done) {
+  it('should export a couple functions', function() {
     (toobusy).should.be.a('function');
     (toobusy.maxLag).should.be.a('function');
     (toobusy.shutdown).should.be.a('function');
-    done();
+    (toobusy.interval).should.be.a('function');
+    (toobusy.shutdown).should.be.a('function');
+    (toobusy).should.not.have.property('start');
   });
@@ -15,19 +18,41 @@ });
 describe('maxLag', function() {
-  it('should default to 70', function(done) {
+  it('should default to 70', function() {
     (toobusy.maxLag()).should.equal(70);
-    done();
   });
-  it('should throw an exception for values < 10', function(done) {
+  it('should throw an exception for values < 10', function() {
     (function() { toobusy.maxLag(9); }).should.throw;
-    done();
   });
-  it('should be configurable', function(done) {
+  it('should be configurable', function() {
     (toobusy.maxLag(50)).should.equal(50);
     (toobusy.maxLag(10)).should.equal(10);
     (toobusy.maxLag()).should.equal(10);
-    done();
   });
 });
 
+describe('interval', function() {
+  it('should default to 500', function() {
+    (toobusy.interval()).should.equal(500);
+  });
+  it('should throw an exception for values < 16', function() {
+    (function() { toobusy.interval(15); }).should.throw;
+  });
+  it('should be configurable', function() {
+    (toobusy.interval(250)).should.equal(250);
+    (toobusy.interval(300)).should.equal(300);
+    (toobusy.interval()).should.equal(300);
+  });
+});
+
 describe('toobusy()', function() {
+  // Set lower thresholds for each of these tests.
+  // Resetting the interval() also resets the internal lag counter, which
+  // is nice for making these tests independent of each other.
+  beforeEach(function() {
+    toobusy.maxLag(10);
+    toobusy.interval(250);
+  });
+  afterEach(function() {
+    toobusy.maxLag(70);
+    toobusy.interval(500);
+  });
   it('should return true after a little load', function(done) {
@@ -37,3 +62,3 @@ function load() {
       var start = new Date();
-      while ((new Date() - start) < 250) {
+      while ((new Date() - start) < 100) {
         for (var i = 0; i < 1e5;) i++;
@@ -55,3 +80,3 @@ }
       var start = new Date();
-      while ((new Date() - start) < 250) {
+      while ((new Date() - start) < 100) {
         for (var i = 0; i < 1e5;) i++;
@@ -58,0 +83,0 @@ }

toobusy.js

@@ -1,4 +0,6 @@
-var setInterval = require("timers").setInterval;
-var clearInterval = require("timers").clearInterval;
+'use strict';
 
+//
+// Constants
+// 
 var STANDARD_HIGHWATER = 70;
@@ -12,15 +14,17 @@ var STANDARD_INTERVAL = 500;
 
-var lastTime = new Date().valueOf(), now, lag, highWater = STANDARD_HIGHWATER, interval = STANDARD_INTERVAL, currentLag = 0;
+// 
+// Vars
+//
 
-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);
+var lastTime = new Date().valueOf();
+var highWater = STANDARD_HIGHWATER;
+var interval = STANDARD_INTERVAL;
+var currentLag = 0;
+var checkInterval;
 
-// Don't keep process open just for this timer.
-checkInterval.unref();
 
+/**
+ * Main export function.
+ * @return {Boolean} True if node process is too busy.
+ */
 var toobusy = function(){
@@ -31,10 +35,44 @@ // If current lag is < 2x the highwater mark, we don't always call it 'too busy'. E.g. with a 50ms lag
   var pctToBlock = (currentLag - highWater) / highWater;
-  var rand = Math.random();
-  return rand < pctToBlock;
+  return Math.random() < pctToBlock;
 };
 
+/**
+ * Sets or gets the current check interval.
+ * If you want more sensitive checking, set a faster (lower) interval. A lower maxLag can also create a more
+ * sensitive check.
+ * @param  {Number} [newInterval] New interval to set. If not provided, will return the existing interval.
+ * @return {Number}               New or existing interval.
+ */
+toobusy.interval = function(newInterval) {
+  if (!newInterval) return interval;
+  if (typeof newInterval !== "number") throw new Error("Interval must be a number.");
+
+  newInterval = Math.round(newInterval);
+  if(newInterval < 16) throw new Error("Maximum lag should be greater than 16ms.");
+
+  toobusy.shutdown();
+  interval = newInterval;
+  start();
+  return interval;
+};
+
+/**
+ * Returns last lag reading from last check interval.
+ * @return {Number} Lag in ms.
+ */
 toobusy.lag = function(){
-  return parseInt(currentLag, 10);
+  return Math.round(currentLag);
 };
 
+/**
+ * Set or get the current max latency threshold. Default is 70ms. 
+ *
+ * Note that if event loop lag goes over this threshold, the process is not always 'too busy' - the farther
+ * it goes over the threshold, the more likely the process will be considered too busy.
+ *
+ * The percentage is equal to the percent over the max lag threshold. So 1.25x over the maxLag will indicate
+ * too busy 25% of the time. 2x over the maxLag threshold will indicate too busy 100% of the time.
+ * @param  {Number} [newLag] New maxLag (highwater) threshold.
+ * @return {Number}          New or existing maxLag (highwater) threshold.
+ */
 toobusy.maxLag = function(newLag){
@@ -44,9 +82,6 @@ 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.";
-  }
+  if (typeof interval !== "number") throw new Error("MaxLag must be a number.");
+  newLag = Math.round(newLag);
+  if(newLag < 10) throw new Error("Maximum lag should be greater than 10ms.");
+
   highWater = newLag;
@@ -56,6 +91,30 @@ return highWater;
 
+/**
+ * Shuts down toobusy.
+ *
+ * Not necessary to call this manually, only do this if you know what you're doing. `unref()` is called
+ * on toobusy's check interval, so it will never keep the server open.
+ */
 toobusy.shutdown = function(){
+  currentLag = 0;
   clearInterval(checkInterval);
 };
 
-module.exports = toobusy;
+/**
+ * Private - starts checking lag.
+ */
+function start() {
+  checkInterval = setInterval(function(){
+    var now = Date.now();
+    var lag = now - lastTime;
+    lag = Math.max(0, lag - interval);
+    // Dampen lag. See AVG_DECAY_FACTOR initialization at the top of this file.
+    currentLag = (lag + (currentLag * (AVG_DECAY_FACTOR - 1))) / AVG_DECAY_FACTOR;
+    lastTime = now;
+  }, interval);
+
+  // Don't keep process open just for this timer.
+  checkInterval.unref();
+}
+
+module.exports = toobusy;

No alert changes

Improved metrics

Total package byte prevSize

14770

increased by23.27%

Lines of code

314

increased by33.05%

Number of lines in readme file

107

increased by0.94%

Worsened metrics

Dev dependency count

3

increased by50%

No dependency changes