nodemailer/redfour

Name: redfour

Owner: nodemailer

Description: A redis binary semaphore with async wait

Forked from: mixmaxhq/redfour

Created: 2017-10-03 07:11:44.0

Updated: 2018-04-16 18:27:58.0

Pushed: 2017-10-03 08:11:21.0

Homepage: null

Size: 38

Language: JavaScript

GitHub Committers

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README

ioredfour

Originally forked from redfour. Main difference being that redfour uses node_redis + node-redis-scripty while ioredfour uses ioredis.

Install

or

install ioredfour --save

Usage example

Lock = require('ioredfour');

testLock = new Lock({
 Can also be an `Object` of options to pass to `new Redis()`
 https://www.npmjs.com/package/ioredis#connect-to-redis, or an existing
 instance of `ioredis` (if you want to reuse one connection, though this
 module must create a second).
dis: 'redis://localhost:6379',
mespace: 'mylock'

id = Math.random();
firstlock;

irst, acquire the lock.
Lock.acquireLock(id, 60 * 1000 /* Lock expires after 60sec if not released */ , function(err, lock) {
 (err) {
console.log('error acquiring', err);
else if (!lock.success) {
console.log('lock exists', lock);
else {
console.log('lock acquired initially');
firstlock = lock;



nother server might be waiting for the lock like this.
Lock.waitAcquireLock(id, 60 * 1000 /* Lock expires after 60sec */ , 10 * 1000 /* Wait for lock for up to 10sec */ , function(err, lock) {
 (err) {
console.log('error wait acquiring', err);
else {
console.log('lock acquired after wait!', lock);



hen the original lock is released, `waitAcquireLock` is fired on the other server.
imeout(() => {
stLock.releaseLock(firstlock, (err) => {
if (err) {
  console.log('error releasing', err);
} else {
  console.log('released lock');
}
;
 * 1000);

Contributing

We welcome pull requests! Please lint your code.

Release History

• 1.0.2-ioredis Forked from redfour and switch node_redis with ioredis
• 1.0.2 Don't use instanceof to determine if the redis constructor option is of

  type `redis.RedisClient`.
  

• 1.0.1 Fix issue where you could only pass in a Redis connection URI.
• 1.0.0 Initial release.

Etymology

Shortened (and easier to pronouce) version of “Redis Semaphore”