Solo

Solo is a Javascript library that runs a process across NodeJS instances with the warranty that only one process will be active at the time.

Locking is implemented with Redis, using redislock library.

Install

For NodeJS, use npm:

npm install --save solo-worker

Use

Load Solo and start it with 3 parameters:

parameter	type	description
id	string	A string to identify this worker. It's warrantied that only 1 worker of the same id will be running at any time.
options	object	An object to specify the configuration options for the worker.
worker	function	The function that will act as the worker.

Options available are:

option	type	description
host	string	The host where the redis server is located.
port	number	The port where the redis server is located.
interval	number	The interval (in ms) to restart a work after one has finished (default: 0).
ttl	number	The timeout (in ms) to expire the lock (default: 1000).
ping	number	The interval (in ms) when pings occurs for inactive workers (default: 1000).
prefix	number	The prefix to store keys in redis (default: "solo").

when worker function is executed, a callback is passed with 2 parameters: error and solo; this last one is an object with functions to interact with the library. It has the following methods:

solo.touch(callback)

Restarts the ttl of the worker which is running.

solo.extend(time, callback)

Extend the time of expiration of the current worker by time given in milliseconds.

solo.done(callback)

It must be called to end the current work and trigger the interval the let other work starts latter.

Example

const solo = require('./lib/index');

const options = {
  host: '127.0.0.1',
  port: 6379,
  ttl: 7000,
  ping: 3000,
  interval: 5000
};

solo('process1', options, (error, worker) => {
    console.log('Doing process 1');
    setTimeout(() => worker.done(), 2000);
});

License

The MIT License (MIT)

Copyright (c) 2015 VoxFeed

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.