retry-function

Wrapper to retry function calls with an exponential backoff strategy

Installation:

npm install --save screwdriver-retry-function

Usage:

Pass a function and callback to retryFn and it will retry with exponential backoff.

var retryFn = require('retry-function');

var myFunc = function (cb) {return process.nextTick(cb(null, 'foo'))},
    myCallback = function (err, data) {};

retryFn({
    method: myFunc
}, myCallback);

Configuring retry

Uses retry to implement retries. You can use the same config with retryFn.

options is a JS object that can contain any of the following keys:

• retries: The maximum amount of times to retry the operation. Default is 10.
• factor: The exponential factor to use. Default is 2.
• minTimeout: The number of milliseconds before starting the first retry. Default is 1000.
• maxTimeout: The maximum number of milliseconds between two retries. Default is Infinity.
• randomize: Randomizes the timeouts by multiplying with a factor between 1 to 2. Default is false.

var retryFn = require('retry-function');

var myFunc = function (cb) {return process.nextTick(cb(null, 'foo'))},
    myCallback = function (err, data) {};

retryFn({
    method: myFunc,
    options: {
        retries: 5
    }
}, myCallback);

Conditional Retry

You may add a function that inspects the error from a run of method to determine if a retry is desired. For example, you may wish to retry calls that result in a 500 error, but not those that result in a 400.

var retryFn = require('retry-function');

var myFunc = function (cb) {return process.nextTick(cb(null, 'foo'))},
    myCallback = function (err, data) {};

retryFn({
    method: myFunc,
    shouldRetry: function (err) { return err.code >= 500; }
}, myCallback);

Additional args

You may need to pass additional arguments to your method. You may do so by adding an arguments array to the retryFn config. The same arguments will be passed to each execution of the method.

var retryFn = require('retry-function');

var myFunc = function (args, cb) {return process.nextTick(cb(null, 'foo'))},
    myCallback = function (err, data) {};

retryFn({
    method: myFunc,
    arguments: ['foo']
}, myCallback);

Code licensed under the MIT license. See LICENSE file for terms.