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mortice

2.0.0 • Public • Published

mortice

Build status

Isomorphic read/write lock that works in single processes, node clusters and web workers.

Features

  • Reads occur concurrently
  • Writes occur one at a time
  • No reads occur while a write operation is in progress
  • Locks can be created with different names
  • Reads/writes can time out

Install

$ npm install --save mortice

Usage

const mortice = require('mortice')
const delay = require('delay')
 
// the lock name & options objects are both optional
const mutex = mortice('my-lock', {
 
  // how long before write locks time out (default: 24 hours)
  timeout: 30000,
 
   // control how many read operations are executed concurrently (default: Infinity)
  concurrency: 5,
 
  // by default the the lock will be held on the main thread, set this to true if the
  // a lock should reside on each worker (default: false)
  singleProcess: false
})
 
Promise.all([
  (async () => {
    const release = await mutex.readLock()
 
    try {
      console.info('read 1')
    } finally {
      release()
    }
  })(),
  (async () => {
    const release = await mutex.readLock()
 
    try {
      console.info('read 2')
    } finally {
      release()
    }
  })(),
  (async () => {
    const release = await mutex.writeLock()
 
    try {
      await delay(1000)
 
      console.info('write 1')
    } finally {
      release()
    }
  })(),
  (async () => {
    const release = await mutex.readLock()
 
    try {
      console.info('read 3')
    } finally {
      release()
    }
  })()
])
read 1
read 2
<small pause>
write 1
read 3

Browser

Because there's no global way to evesdrop on messages sent by Web Workers, please pass all created Web Workers to the observable-webworkers module:

// main.js
const mortice = require('mortice')
const observe = require('observable-webworkers')
 
// create our lock on the main thread, it will be held here
const mutex = mortice()
 
const worker = new Worker('worker.js')
 
observe(worker)
// worker.js
const mortice = require('mortice')
const delay = require('delay')
 
const mutex = mortice()
 
let release = await mutex.readLock()
// read something
release()
 
release = await mutex.writeLock()
// write something
release()

Alternatively you can use the bundled mortice.Worker to create web workers and save yourself an extra dependency.

const mortice = require('mortice')
const Worker = mortice.Worker
 
// create our lock on the main thread, it will be held here
const mutex = mortice()
 
const worker = new Worker('worker.js')

install

npm i mortice

Downloadsweekly downloads

3,419

version

2.0.0

license

ISC

homepage

github.com

repository

Gitgithub

last publish

collaborators

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