https://github.com/harish2704/node-standalone-mutex

A standalone Mutex implementation for Nodejs which depends on Nodes inter-process communication
https://github.com/harish2704/node-standalone-mutex

cluster lock mutex nodejs promise

Last synced: about 1 month ago
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A standalone Mutex implementation for Nodejs which depends on Nodes inter-process communication

• Host: GitHub
• URL: https://github.com/harish2704/node-standalone-mutex
• Owner: harish2704
• License: mit
• Created: 2017-07-05T03:37:47.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2017-07-06T05:30:42.000Z (over 7 years ago)
• Last Synced: 2024-11-13T08:39:18.262Z (about 2 months ago)
• Topics: cluster, lock, mutex, nodejs, promise
• Language: JavaScript
• Size: 5.86 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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# standalone-mutex

A standalone Mutex implementation for Nodejs which depends on Nodes inter-process communication

## Installation

```

npm i standalone-mutex

```

## Usage

### Example

Below code can be found in `example` directory

```javascript

const cluster = require('cluster');

const numCPUs = parseInt( process.env.THREAD_COUNT || require('os').cpus().length );

const Mutex = require('standalone-mutex');

const log = console.log.bind( console, 'Info: ');

const MID = 'asdf65498'; // A unique id for indentifying our mutex.

function delay( ms ){

  return new Promise(function(resolve){

    setTimeout( resolve, ms );

  });

}

function doAsync( pid ){

  let mutex;

  return Mutex.acquire( MID )

  .then(function( m ){

    mutex = m;

    log('doAsync:start ' + pid );

    return delay(2000);

  })

  .then(function(){

    log('doAsync:done ' + pid );

    return mutex.release();

  });

}

function master(){

  log(`Master ${process.pid} is running`);

  // Fork workers.

  for (let i = 0; i < numCPUs; i++) {

    cluster.fork();

  }

  Mutex.init();

  doAsync( process.pid ).catch( log );

  cluster.on('exit', (worker, code, signal) => {

    log(`worker ${worker.process.pid} died ${signal}`);

  });

}

function slave(){

  doAsync( process.pid )

    .catch(function(err){

      log( 'Error', err );

    })

    .then(function(){

      log( `Completed ${process.pid}`);

    });

  log(`Worker ${process.pid} started`);

}

if (cluster.isMaster) {

  master();

} else {

  slave();

}

```