1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
import wrapAsync from './internal/wrapAsync';
import { promiseCallback, PROMISE_SYMBOL } from './internal/promiseCallback';
function constant(value) {
return function () {
return value;
}
}
/**
* Attempts to get a successful response from `task` no more than `times` times
* before returning an error. If the task is successful, the `callback` will be
* passed the result of the successful task. If all attempts fail, the callback
* will be passed the error and result (if any) of the final attempt.
*
* @name retry
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @see [async.retryable]{@link module:ControlFlow.retryable}
* @param {Object|number} [opts = {times: 5, interval: 0}| 5] - Can be either an
* object with `times` and `interval` or a number.
* * `times` - The number of attempts to make before giving up. The default
* is `5`.
* * `interval` - The time to wait between retries, in milliseconds. The
* default is `0`. The interval may also be specified as a function of the
* retry count (see example).
* * `errorFilter` - An optional synchronous function that is invoked on
* erroneous result. If it returns `true` the retry attempts will continue;
* if the function returns `false` the retry flow is aborted with the current
* attempt's error and result being returned to the final callback.
* Invoked with (err).
* * If `opts` is a number, the number specifies the number of times to retry,
* with the default interval of `0`.
* @param {AsyncFunction} task - An async function to retry.
* Invoked with (callback).
* @param {Function} [callback] - An optional callback which is called when the
* task has succeeded, or after the final failed attempt. It receives the `err`
* and `result` arguments of the last attempt at completing the `task`. Invoked
* with (err, results).
* @returns {Promise} a promise if no callback provided
*
* @example
*
* // The `retry` function can be used as a stand-alone control flow by passing
* // a callback, as shown below:
*
* // try calling apiMethod 3 times
* async.retry(3, apiMethod, function(err, result) {
* // do something with the result
* });
*
* // try calling apiMethod 3 times, waiting 200 ms between each retry
* async.retry({times: 3, interval: 200}, apiMethod, function(err, result) {
* // do something with the result
* });
*
* // try calling apiMethod 10 times with exponential backoff
* // (i.e. intervals of 100, 200, 400, 800, 1600, ... milliseconds)
* async.retry({
* times: 10,
* interval: function(retryCount) {
* return 50 * Math.pow(2, retryCount);
* }
* }, apiMethod, function(err, result) {
* // do something with the result
* });
*
* // try calling apiMethod the default 5 times no delay between each retry
* async.retry(apiMethod, function(err, result) {
* // do something with the result
* });
*
* // try calling apiMethod only when error condition satisfies, all other
* // errors will abort the retry control flow and return to final callback
* async.retry({
* errorFilter: function(err) {
* return err.message === 'Temporary error'; // only retry on a specific error
* }
* }, apiMethod, function(err, result) {
* // do something with the result
* });
*
* // to retry individual methods that are not as reliable within other
* // control flow functions, use the `retryable` wrapper:
* async.auto({
* users: api.getUsers.bind(api),
* payments: async.retryable(3, api.getPayments.bind(api))
* }, function(err, results) {
* // do something with the results
* });
*
*/
const DEFAULT_TIMES = 5;
const DEFAULT_INTERVAL = 0;
export default function retry(opts, task, callback) {
var options = {
times: DEFAULT_TIMES,
intervalFunc: constant(DEFAULT_INTERVAL)
};
if (arguments.length < 3 && typeof opts === 'function') {
callback = task || promiseCallback();
task = opts;
} else {
parseTimes(options, opts);
callback = callback || promiseCallback();
}
if (typeof task !== 'function') {
throw new Error("Invalid arguments for async.retry");
}
var _task = wrapAsync(task);
var attempt = 1;
function retryAttempt() {
_task((err, ...args) => {
if (err === false) return
if (err && attempt++ < options.times &&
(typeof options.errorFilter != 'function' ||
options.errorFilter(err))) {
setTimeout(retryAttempt, options.intervalFunc(attempt));
} else {
callback(err, ...args);
}
});
}
retryAttempt();
return callback[PROMISE_SYMBOL]
}
function parseTimes(acc, t) {
if (typeof t === 'object') {
acc.times = +t.times || DEFAULT_TIMES;
acc.intervalFunc = typeof t.interval === 'function' ?
t.interval :
constant(+t.interval || DEFAULT_INTERVAL);
acc.errorFilter = t.errorFilter;
} else if (typeof t === 'number' || typeof t === 'string') {
acc.times = +t || DEFAULT_TIMES;
} else {
throw new Error("Invalid arguments for async.retry");
}
}
|
