Merge pull request #1058 from caolan/retryable

added retryable wrapper for async tasks

README.md

@@ -221,6 +221,7 @@ Some functions are also available in the following forms:
 * [`auto`](#auto)
 * [`autoInject`](#autoInject)
 * [`retry`](#retry)
+* [`retryable`](#retryable)
 * [`iterator`](#iterator)
 * [`times`](#times), `timesSeries`, `timesLimit`
 * [`race`](#race)
@@ -1580,6 +1581,31 @@ async.auto({
 });
 ```
 
+
+---------------------------------------
+
+<a name="retryable"></a>
+
+### retryable([opts = {times: 5, interval: 0}| 5], task)
+
+A close relative of `retry`.  This method wraps a task and makes it retryable, rather than immediately calling it with retries.
+
+__Arguments__
+
+* `opts` - optional options, exactly the same as from `retry`
+* `task` - the asynchronous function to wrap
+
+__Example__
+
+```js
+async.auto({
+    dep1: async.retryable(3, getFromFlakyService),
+    process: ["dep1", async.retryable(3, function (results, cb) {
+        maybeProcessData(results.dep1, cb)
+    })]
+}, callback)
+```
+
 ---------------------------------------
 
 <a name="iterator"></a>

lib/index.js

@@ -51,6 +51,7 @@ import reject from './reject';
 import rejectLimit from './rejectLimit';
 import rejectSeries from './rejectSeries';
 import retry from './retry';
+import retryable from './retryable';
 import seq from './seq';
 import series from './series';
 import setImmediate from './setImmediate';
@@ -120,6 +121,7 @@ export default {
     rejectLimit: rejectLimit,
     rejectSeries: rejectSeries,
     retry: retry,
+    retryable: retryable,
     seq: seq,
     series: series,
     setImmediate: setImmediate,
@@ -207,6 +209,7 @@ export {
     rejectLimit as rejectLimit,
     rejectSeries as rejectSeries,
     retry as retry,
+    retryable as retryable,
     seq as seq,
     series as series,
     setImmediate as setImmediate,

lib/retryable.js

@@ -0,0 +1,20 @@
+import retry from './retry';
+import rest from 'lodash/rest';
+
+export default function (opts, task) {
+    if (!task) {
+        task = opts;
+        opts = null;
+    }
+    return rest(function (args) {
+        var callback = args.pop();
+
+        function taskFn(cb) {
+            task.apply(null, args.concat([cb]));
+        }
+
+        if (opts) retry(opts, taskFn, callback);
+        else retry(taskFn, callback);
+
+    });
+}

mocha_test/retryable.js

@@ -0,0 +1,64 @@
+var async = require('../lib');
+var expect = require('chai').expect;
+var assert = require('assert');
+
+describe('retryable', function () {
+    it('basics', function (done) {
+        var calls = 0;
+        var retryableTask = async.retryable(3, function (arg, cb) {
+            calls++;
+            expect(arg).to.equal(42);
+            cb('fail');
+        });
+
+        retryableTask(42, function (err) {
+            expect(err).to.equal('fail');
+            expect(calls).to.equal(3);
+            done();
+        });
+
+        setTimeout(function () {
+        }, 15);
+    });
+
+    it('should work as an embedded task', function(done) {
+        var retryResult = 'RETRY';
+        var fooResults;
+        var retryResults;
+
+        async.auto({
+            dep: async.constant('dep'),
+            foo: ['dep', function(results, callback){
+                fooResults = results;
+                callback(null, 'FOO');
+            }],
+            retry: ['dep', async.retryable(function(results, callback) {
+                retryResults = results;
+                callback(null, retryResult);
+            })]
+        }, function(err, results){
+            assert.equal(results.retry, retryResult, "Incorrect result was returned from retry function");
+            assert.equal(fooResults, retryResults, "Incorrect results were passed to retry function");
+            done();
+        });
+    });
+
+    it('should work as an embedded task with interval', function(done) {
+        var start = new Date().getTime();
+        var opts = {times: 5, interval: 100};
+
+        async.auto({
+            foo: function(callback){
+                callback(null, 'FOO');
+            },
+            retry: async.retryable(opts, function(callback) {
+                callback('err');
+            })
+        }, function(){
+            var duration = new Date().getTime() - start;
+            var expectedMinimumDuration = (opts.times -1) * opts.interval;
+            assert(duration >= expectedMinimumDuration, "The duration should have been greater than " + expectedMinimumDuration + ", but was " + duration);
+            done();
+        });
+    });
+});

test/test-async.js

@@ -278,48 +278,6 @@ exports['seq without callback'] = function (test) {
     add2mul3.call(testcontext, 3);
 };
 
-// need to fix retry, this isn't working
-/*
-exports['retry as an embedded task'] = function(test) {
-    var retryResult = 'RETRY';
-    var fooResults;
-    var retryResults;
-
-    async.auto({
-        dep: async.constant('dep'),
-        foo: ['dep', function(results, callback){
-            fooResults = results;
-            callback(null, 'FOO');
-        }],
-        retry: ['dep', async.retry(function(results, callback) {
-            retryResults = results;
-            callback(null, retryResult);
-        })]
-    }, function(err, results){
-        test.equal(results.retry, retryResult, "Incorrect result was returned from retry function");
-        test.equal(fooResults, retryResults, "Incorrect results were passed to retry function");
-        test.done();
-    });
-};
-
-exports['retry as an embedded task with interval'] = function(test) {
-    var start = new Date().getTime();
-    var opts = {times: 5, interval: 100};
-
-    async.auto({
-        foo: function(callback){
-            callback(null, 'FOO');
-        },
-        retry: async.retry(opts, function(callback) {
-            callback('err');
-        })
-    }, function(){
-        var duration = new Date().getTime() - start;
-        var expectedMinimumDuration = (opts.times -1) * opts.interval;
-        test.ok(duration >= expectedMinimumDuration, "The duration should have been greater than " + expectedMinimumDuration + ", but was " + duration);
-        test.done();
-    });
-};*/
 
 exports['parallel'] = function(test){
     var call_order = [];