Added onMeasuredLag event

CHANGELOG.md

@@ -1,3 +1,6 @@
+### 0.6.2
+  * Added `onMeasuredLag` event. Thanks @nachooya
+
 ### 0.6.1
   * Added metricsPrev paramater to `onLag` event. Thanks @nachooya
 

README.md

@@ -99,6 +99,10 @@ toobusy.onLag(function(currentLag, metrics, metricsPrev) {
   console.log("Metrics during interval: ", metrics);
   console.log("Metrics previous interval: ", metricsPrev);
 });
+
+toobusy.onMeasuredLag(function(currentLag, maxLag, interval) {
+  console.log("Measured Lag during last interval: '+currentLag);
+})
 ```
 
 The default maxLag value is 70ms, and the default check interval is 500ms.

package.json

@@ -2,7 +2,7 @@
   "name": "toobusy-why",
   "description": "Don't fall over when your Node.JS server is too busy. Now without native dependencies and metrics support!",
   "homepage": "https://github.com/nachooya/node-toobusy",
-  "version": "0.6.1",
+  "version": "0.6.2",
   "dependencies": {},
   "devDependencies": {
     "mocha": "1.7.0",

tests.js

@@ -210,4 +210,27 @@ describe('started', function() {
   });
 });
 
+describe('onMeasuredLag event', function() {
+  it('should emit onMeasuredLag event every configured interval', function(done) {
+
+    var timesCalled = 5;
+    var meanLag = 0;
+    toobusy.maxLag(10);
+    toobusy.interval(100);
+
+    toobusy.onMeasuredLag(function(currentLag, maxLag, interval) {
+        timesCalled--;
+        (currentLag).should.be.above(0);
+        (maxLag).should.be.equal(10);
+        (interval).should.be.equal(100);
+        meanLag += currentLag;
+        if (timesCalled === 0) {
+            console.log ('meanLag: '+(meanLag/5));
+            toobusy.shutdown();
+            done();
+        }
+    });
+
+  });
+});
 

toobusy.js

@@ -8,6 +8,7 @@ var events = require('events');
 var STANDARD_HIGHWATER = 70;
 var STANDARD_INTERVAL = 500;
 var LAG_EVENT = "LAG_EVENT";
+var MEASURED_LAG_EVENT= "MEASURED_LAG_EVENT";
 
 // A dampening factor.  When determining average calls per second or
 // current lag, we weigh the current value against the previous value 2:1
@@ -144,6 +145,14 @@ toobusy.onLag = function (fn, threshold) {
   eventEmitter.on(LAG_EVENT, fn);
 };
 
+/**
+ * Registers an event listener for measured lag events,
+ * @param {Function}  fn  Function of form onLag(value: number, maxLag: number, interval: number) => void
+ */
+toobusy.onMeasuredLag = function (fn) {
+  eventEmitter.on(MEASURED_LAG_EVENT, fn);
+};
+
 toobusy.metric = function (name, value) {
 
   if (!metrics[name]) metrics[name] = 0;
@@ -167,6 +176,8 @@ function start() {
       eventEmitter.emit(LAG_EVENT, currentLag, metrics, metricsPrev);
     }
 
+    eventEmitter.emit(MEASURED_LAG_EVENT, currentLag, lagEventThreshold, interval);
+
     metricsPrev = metrics;
     metrics = {};