Async / Await exponential retry
Purpose
Minimalist, efficient and performance focused retry system. Basically it helps developer to retry a function with a specific interval, exponential factor etc.
No dependency.
Compatibility
/!\ This module use async/await syntax, this is why you must have node 7.6+.
Supported and tested : >= 7.6
| Version | Supported | Tested |
|---|---|---|
| 20.x | yes | yes |
| 18.x | yes | yes |
| 16.x | yes | yes |
| 14.x | yes | yes |
| 12.x | no | yes |
| 10.x | no | yes |
| 9.x | no | yes |
| 8.x | no | yes |
| >= 7.6 | no | yes |
Installation
$ npm install async-await-retry --saveUsage
Basic usage
const retry = require('async-await-retry');
const func = async () => {return new Promise((resolve) => resolve('OK'))};
try {
const res = await retry(func)
} catch (err) {
console.log('The function execution failed !')
}Sync function syntax
const retry = require('async-await-retry');
const func = () => {...};
try {
const res = await retry(func)
console.log(res) // output : OK
} catch (err) {
console.log('The function execution failed !')
}Anonymous function style
const retry = require('async-await-retry');
try {
const res = await retry(async () => {
return new Promise((resolve) => resolve('OK'))
})
console.log(res) // output : OK
} catch (err) {
console.log('The function execution failed !')
}Callback function style
const retry = require('async-await-retry');
try {
const res = await retry((arg1, cb) => {
....
cb(err, data); // send err as first argument
}, ["arg1"], {isCb: true});
} catch (err) {
console.log('The function execution failed !')
}Options
## retry(function, [args], [config])
-
function: function to retry in case of error -
args: your function's parameters in case you don't use callback style -
config: an object containing all retry process options
options
| Option | description | Default value |
|---|---|---|
retriesMax |
Maximum number of retries | 3 |
interval |
Delay in ms between two tentatives | 0 |
exponential |
Will the interval increase exponentially ? | true |
maxBackoff |
Maximum delay before to retry (with exponential) | 30s |
factor |
The exponential factor to use | 2 |
jitter |
Random jitter in ms to add to the interval | 0 |
isCb |
Old callback function style ? | false |
onAttemptFail |
User's callback to manage retry system | default fallback |
An example of custom options :
const retry = require('async-await-retry');
try {
const res = await retry(async () => {
return new Promise((resolve) => resolve('OK'))
}, null, {retriesMax: 4, interval: 100, exponential: true, factor: 3, jitter: 100})
console.log(res) // output : OK
} catch (err) {
console.log('The function execution failed !')
}onAttemptFail
This method can be used to manage, by yourself, the retry system. It's called when an error occurred and before to retry. This method can have three behaviors:
- you can throw an error
- if it returns truthy value then normal retry system continues
- if it returns falsy value then the retry system stop
const retry = require('async-await-retry');
try {
const res = await retry(MyfuncToRetry, null, {
onAttemptFail: (data) => {
// do some stuff here, like logging errors
}
});
} catch (err) {
console.log('The function execution failed !')
}The data argument is an object that can be described like this:
| Property | description |
|---|---|
error |
The current error object |
currentRetry |
The current retry value |
retriesMax |
Maximum number of retries |
interval |
Delay in ms between two tentatives |
exponential |
Will the interval increase exponentially ? |
factor |
The exponential factor to use |
jitter |
Random jitter in ms to add to the interval |
maxBackoff |
Maximum delay before to retry |
Test
$ npm testCoverage report can be found in coverage/.