x-retry

Retry callback based or async function

Example

• Operation

const BusyService = {
  call_times : 0,
  getHelloAtEach3Times : function (must_be_hi, callback) {
    this.call_times++;
    
    if (this.call_times % 3 === 0) {
      return callback(null, 'hello');
    }

    let BusyError = new Error('Service is busy');
    BusyError.status = 503;

    return callback(BusyError);
  },
  asyncGetHelloAtEach3Times : async function (must_be_hi) {
    this.call_times++;
    
    if (this.call_times % 3 === 0) {
      return 'hello';
    }

    let BusyError = new Error('Service is busy');
    BusyError.status = 503;

    throw BusyError;
  }
};

• Async Retry

const { asyncRetry, Timeout } = require('x-retry');

it ('should retry a async function ok after three times', async () => {
  let message = await asyncRetry({
    func      : BusyService.asyncGetHelloAtEach3Times,
    thisArg   : BusyService,
    args      : ['hi'],
    isRetry   : (error) => !(error.status >= 400 && error.status < 500),
    maxRetry  : 3,
    timeout   : Timeout({ minTimeout : 100, maxTimeout : 10000 })
  });

  assert.equal(message, 'hello');
});

• Callback Retry

const { callbackRetry, Timeout } = require('x-retry');

it ('should retry a callback function ok after three times', (done) => {
  callbackRetry({
    func      : BusyService.getHelloAtEach3Times,
    thisArg   : BusyService,
    args      : ['hi'],
    isRetry   : (error) => !(error.status >= 400 && error.status < 500),
    maxRetry  : 3,
    timeout   : Timeout({ minTimeout : 100, maxTimeout : 10000 }),
    callback  : (err, message) => (!err && message === 'hello') ? done() : done(err) 
  });
});

• See more cases in test file

Functions

asyncRetry(options) ⇒ Promise.<any>

Retry an async function

callbackRetry(options) ⇒ void

Retry an callback based function

Timeout([options]) ⇒ function

Create function that generate timeout by exponential backoff algorithm

asyncRetry(options) ⇒ Promise.<any>

Retry a async function

Kind: function
Returns: Promise.<any> - result of async func
Throws:

• ERR_REACHED_MAX_RETRY
• ERR_CANNOT_RETRY when not reached max retry but isRetry() return false.

Param	Type	Default	Description
options	object
options.func	function		async function to retry
[options.thisArg]	object		this pointer apply to function
[options.args]	Array.<any>		arguments of function
[options.isRetry]	function		(error) => boolean
[options.maxRetry]	number	3	max retry times
[options.timeout]	number | function		delay between retry operation, default is generated by Timeout. if is function, must match interface : (retry_count, maxRetry, logs) => number
[options.activity]	string		what is this activity name ? default is func.name
[options.actor]	string		who do this activity ? default is thisArg.name

callbackRetry(options) ⇒ void

Retry an callback based function

Kind: function
Errors: :

• ERR_REACHED_MAX_RETRY
• ERR_CANNOT_RETRY when not reached max retry but isRetry() return false.

Param	Type	Default	Description
options	object
options.func	function		callback based function to retry
[options.thisArg]	object		this pointer apply to function
[options.args]	Array.<any>		arguments of function
options.callback	function		callback of function
[options.isRetry]	function		(error) => boolean
[options.maxRetry]	number	3	max retry times
[options.timeout]	number | function	200	delay between retry operation, , default is generated by Timeout. if is function, must match interface : (retry_count, maxRetry, logs) => number
[options.activity]	string		what is this activity name ? default is func.name
[options.actor]	string		who do this activity ? default is thisArg.name

Timeout([options]) ⇒ function

Create function that generate timeout by exponential backoff algorithm

Kind: function
Returns: function - generate timeout

Param	Type	Default
[options]	Object
[options.minTimeout]	Number	20
[options.maxTimeout]	Number	Infinite
[options.factor]	Number	2
[options.randomize]	Boolean	true

Timeout~generateTimeout([retryCount]) ⇒ number

Generate timeout = Math.min(random * minTimeout * Math.pow(factor, retryCount), maxTimeout)

Kind: inner method of Timeout
Returns: number - timeout

Param	Type	Default
[retryCount]	number	1