retry-as-promised

What is retry-as-promised?

The retry-as-promised npm package allows you to retry a promise-returning function a specified number of times with a delay between each attempt. This is useful for handling transient errors in asynchronous operations, such as network requests or database queries.

What are retry-as-promised's main functionalities?

Basic Retry

This feature allows you to retry a promise-returning function up to a specified number of times (in this case, 3) with a delay between each attempt (in this case, 1000 milliseconds).

const retry = require('retry-as-promised');

const myFunction = () => {
  return new Promise((resolve, reject) => {
    // Simulate an operation that may fail
    if (Math.random() > 0.5) {
      resolve('Success');
    } else {
      reject('Failure');
    }
  });
};

retry(() => myFunction(), { max: 3, timeout: 1000 })
  .then(result => console.log(result))
  .catch(err => console.error(err));

Custom Retry Logic

This feature allows you to customize the retry logic, including the number of retries, the delay between retries, and the conditions under which to retry. In this example, the function will retry up to 5 times with an increasing delay based on the backoffBase and backoffExponent.

const retry = require('retry-as-promised');

const myFunction = () => {
  return new Promise((resolve, reject) => {
    // Simulate an operation that may fail
    if (Math.random() > 0.5) {
      resolve('Success');
    } else {
      reject('Failure');
    }
  });
};

retry(() => myFunction(), {
  max: 5,
  timeout: 2000,
  match: [/Failure/],
  backoffBase: 1000,
  backoffExponent: 1.5
})
  .then(result => console.log(result))
  .catch(err => console.error(err));

Retry with Custom Error Handling

This feature allows you to specify custom error handling logic for retries. In this example, the function will retry up to 4 times with a delay that doubles each time, but only if the error message matches 'Custom Error'.

const retry = require('retry-as-promised');

const myFunction = () => {
  return new Promise((resolve, reject) => {
    // Simulate an operation that may fail
    if (Math.random() > 0.5) {
      resolve('Success');
    } else {
      reject(new Error('Custom Error'));
    }
  });
};

retry(() => myFunction(), {
  max: 4,
  timeout: 1500,
  match: [err => err.message === 'Custom Error'],
  backoffBase: 500,
  backoffExponent: 2
})
  .then(result => console.log(result))
  .catch(err => console.error(err));

Other packages similar to retry-as-promised

promise-retry

The promise-retry package provides similar functionality for retrying promise-returning functions. It allows for customizable retry strategies, including exponential backoff and custom retry conditions. Compared to retry-as-promised, promise-retry offers more flexibility in defining retry strategies and conditions.

async-retry

The async-retry package is another alternative for retrying asynchronous operations. It supports customizable retry strategies, including exponential backoff and custom retry conditions. It is similar to retry-as-promised but offers additional features such as support for async/await syntax and more granular control over retry behavior.

p-retry

The p-retry package is a lightweight library for retrying promise-returning functions. It supports customizable retry strategies, including exponential backoff and custom retry conditions. Compared to retry-as-promised, p-retry is more focused on simplicity and ease of use, making it a good choice for straightforward retry scenarios.

README

retry-as-promised

Retry promises when they fail

Installation

$ npm install --save retry-as-promised
$ yarn add retry-as-promised

Configuration

var retry = require('retry-as-promised').default;

var warningFn = function(msg){ someLoggingFunction(msg, 'notice'); };

// Will call the until max retries or the promise is resolved.
return retry(function (options) {
  // options.current, times callback has been called including this call
  return promise;
}, {
  max: 3, // maximum amount of tries
  timeout: 10000 // throw if no response or error within millisecond timeout, default: undefined,
  match: [ // Must match error signature (ala bluebird catch) to continue
    Sequelize.ConnectionError,
    'SQLITE_BUSY'
  ],
  backoffBase: 1000 // Initial backoff duration in ms. Default: 100,
  backoffExponent: 1.5 // Exponent to increase backoff each try. Default: 1.1
  report: warningFn, // the function used for reporting; must have a (string, object) argument signature, where string is the message that will passed in by retry-as-promised, and the object will be this configuration object + the $current property
  name:  'SourceX' // if user supplies string, it will be used when composing error/reporting messages; else if retry gets a callback, uses callback name in erroring/reporting; else (default) uses literal string 'unknown'
});

Tested with

• Bluebird
• Q