backoff - npm Package Compare versions

Comparing version 1.0.0 to 1.1.0

lib/backoff.js

@@ -18,2 +18,3 @@ /*
     this.backoffStrategy_ = backoffStrategy;
+    this.maxNumberOfRetry_ = -1;
     this.backoffNumber_ = 0;
@@ -30,2 +31,16 @@ this.backoffDelay_ = 0;
 /**
+ * Sets a limit, greater than 0, on the maximum number of backoffs. A 'fail'
+ * event will be emitted when the limit is reached.
+ * @param maxNumberOfRetry The maximum number of backoffs.
+ */
+Backoff.prototype.failAfter = function(maxNumberOfRetry) {
+    if (maxNumberOfRetry < 1) {
+        throw new Error('Maximum number of retry must be greater than 0. ' +
+                        'Actual: ' + maxNumberOfRetry);
+    }
+
+    this.maxNumberOfRetry_ = maxNumberOfRetry;
+};
+
+/**
  * Starts a backoff operation.
@@ -38,5 +53,10 @@ */
 
-    this.backoffDelay_ = this.backoffStrategy_.next();
-    this.timeoutID_ = setTimeout(this.handlers.backoff, this.backoffDelay_);
-    this.emit('backoff', this.backoffNumber_, this.backoffDelay_);
+    if (this.backoffNumber_ === this.maxNumberOfRetry_) {
+        this.emit('fail');
+        this.reset();
+    } else {
+        this.backoffDelay_ = this.backoffStrategy_.next();
+        this.timeoutID_ = setTimeout(this.handlers.backoff, this.backoffDelay_);
+        this.emit('backoff', this.backoffNumber_, this.backoffDelay_);
+    }
 };
@@ -50,3 +70,4 @@
     this.timeoutID_ = -1;
-    this.emit('ready', this.backoffNumber_++, this.backoffDelay_);
+    this.emit('ready', this.backoffNumber_, this.backoffDelay_);
+    this.backoffNumber_++;
 };
@@ -53,0 +74,0 @@

lib/strategy/strategy.js

@@ -49,3 +49,3 @@ /*
  * Retrieves the maximal backoff delay.
- * @return The maximal backoff delay.
+ * @return The maximal backoff delay, in milliseconds.
  */
@@ -58,3 +58,3 @@ BackoffStrategy.prototype.getMaxDelay = function() {
  * Retrieves the initial backoff delay.
- * @return The initial backoff delay.
+ * @return The initial backoff delay, in milliseconds.
  */
@@ -79,2 +79,3 @@ BackoffStrategy.prototype.getInitialDelay = function() {
  * @return The backoff delay, in milliseconds.
+ * @protected
  */
@@ -94,2 +95,3 @@ BackoffStrategy.prototype.next_ = function() {
  * Resets the backoff delay to its initial value.
+ * @protected
  */
@@ -96,0 +98,0 @@ BackoffStrategy.prototype.reset_ = function() {

package.json

 {
     "name": "backoff",
     "description": "Fibonacci and exponential backoffs.",
-    "version": "1.0.0",
+    "version": "1.1.0",
     "author": "Mathieu Turcotte <[e-mail]>",
@@ -14,6 +14,6 @@ "keywords": ["backoff", "fibonacci", "exponential"],
         "nodeunit": "0.7",
-        "jshint": "0.7"
+        "jshint": "0.9"
     },
     "scripts": {
-        "pretest": "node_modules/jshint/bin/hint lib/*.js lib/strategy/*.js tests/*.js examples/*.js",
+        "pretest": "node_modules/jshint/bin/hint lib/ lib/ tests/ examples/ index.js",
         "test": "node_modules/nodeunit/bin/nodeunit tests/"
@@ -20,0 +20,0 @@ },

README.md

@@ -6,13 +6,15 @@ # Backoff for Node.js [![Build Status](https://secure.travis-ci.org/MathieuTurcotte/node-backoff.png?branch=master)](http://travis-ci.org/MathieuTurcotte/node-backoff)
 ## Installation
+
 ```
 npm install backoff
 ```
-## Usage
 
-In order to use backoff, require `backoff`.
+## Unit tests
 
-```js
-var backoff = require('backoff');
 ```
+npm test
+```
 
+## Usage
+
 The usual way to instantiate a new `Backoff` object is to use one predefined
@@ -27,10 +29,15 @@ factory method: `backoff.fibonacci([options])`, `backoff.exponential([options])`.
 ``` js
+var backoff = require('backoff');
+
 var fibonacciBackoff = backoff.fibonacci({
     randomisationFactor: 0,
     initialDelay: 10,
-    maxDelay: 1000
+    maxDelay: 300
 });
 
+fibonacciBackoff.failAfter(10);
+
 fibonacciBackoff.on('backoff', function(number, delay) {
-    // Do something when backoff starts.
+    // Do something when backoff starts, e.g. show to the
+    // user the delay before next reconnection attempt.
     console.log(number + ' ' + delay + 'ms');
@@ -40,8 +47,13 @@ });
 fibonacciBackoff.on('ready', function(number, delay) {
-    // Do something when backoff ends.
-    if (number < 15) {
-        fibonacciBackoff.backoff();
-    }
+    // Do something when backoff ends, e.g. retry a failed
+    // operation (DNS lookup, API call, etc.).
+    fibonacciBackoff.backoff();
 });
 
+fibonacciBackoff.on('fail', function() {
+    // Do something when the maximum number of backoffs is
+    // reached, e.g. ask the user to check its connection.
+    console.log('fail');
+});
+
 fibonacciBackoff.backoff();
@@ -61,14 +73,9 @@ ```
 7 210ms
-8 340ms
-9 550ms
-10 890ms
-11 1000ms
-12 1000ms
-13 1000ms
-14 1000ms
-15 1000ms
+8 300ms
+9 300ms
+fail
 ```
 
-Backoff objects are meant to be instantiated once and reused several times
-by calling `reset` after a successful "retry".
+Note that `Backoff` objects are meant to be instantiated once and reused
+several times by calling `reset` after a successful "retry".
 
@@ -106,2 +113,11 @@ ## API
 
+#### backoff.failAfter(numberOfBackoffs)
+
+- numberOfBackoffs: maximum number of backoffs before the fail event gets
+emitted, must be greater than 0
+
+Sets a limit on the maximum number of backoffs that can be performed before
+a fail event gets emitted and the backoff instance is reset. By default, there
+is no limit on the number of backoffs that can be performed.
+
 #### backoff.backoff()
@@ -142,2 +158,9 @@
 
+#### Event: 'fail'
+
+Emitted when the maximum number of backoffs is reached. This event will only
+be emitted if the client has set a limit on the number of backoffs by calling
+`backoff.failAfter(numberOfBackoffs)`. The backoff instance is automatically
+reset after this event is emitted.
+
 ### Interface BackoffStrategy
@@ -144,0 +167,0 @@

tests/backoff.js

@@ -74,2 +74,23 @@ /*
 
+    "the fail event should be emitted when backoff limit is reached": function(test) {
+        this.backoffStrategy.next.returns(10);
+        var spy = new sinon.spy();
+        this.backoff.on('fail', spy);
+
+        this.backoff.failAfter(2);
+
+        // Consume first 2 backoffs.
+        for (var i = 0; i < 2; i++) {
+            this.backoff.backoff();
+            this.clock.tick(10);
+        }
+
+        // Failure should occur on the third call, and not before.
+        test.ok(!spy.calledOnce);
+        this.backoff.backoff();
+        test.ok(spy.calledOnce);
+
+        test.done();
+    },
+
     "calling backoff while a backoff is in progress should throw an error": function(test) {
@@ -88,2 +109,10 @@ this.backoffStrategy.next.returns(10);
 
+    "backoff limit should be greater than 0": function(test) {
+        var backoff = this.backoff;
+        test.throws(function() {
+            backoff.failAfter(0);
+        });
+        test.done();
+    },
+
     "reset should cancel any backoff in progress": function(test) {
@@ -110,2 +139,15 @@ this.backoffStrategy.next.returns(10);
 
+    "backoff should be reset after fail": function(test) {
+        this.backoffStrategy.next.returns(10);
+
+        this.backoff.failAfter(1);
+
+        this.backoff.backoff();
+        this.clock.tick(10);
+        this.backoff.backoff();
+
+        test.ok(this.backoffStrategy.reset.calledOnce);
+        test.done();
+    },
+
     "the backoff number should increase from 0 to N - 1": function(test) {
@@ -112,0 +154,0 @@ this.backoffStrategy.next.returns(10);

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Improved metrics

Total package byte prevSize

32969

increased by14.5%

Number of package files

23

increased by9.52%

Lines of code

645

increased by17.27%

Number of lines in readme file

199

increased by13.07%

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