Lockup

Lockup uses a certain lock file to queue and deal with inter-process asynchronous resources.

Installation

npm install lockup --save

Usage

var lockup = require('lockup');

lockup.lock(file [, options={}], callback);

Create a lock if the lock is not existed, and run the callback function.

If the lock already exists, callback will put in a queue which will be executed and cleaned up once the lock is released.

Notice that, lockup.lock could work with multiple processes.

file path

The path of the lock file.

options Object={}

Optional, default to {};

callback function(err)

The callback function.

err Error|String

Error instance or error message.

lockup.unlock(file)

Release a lock.

Examples

var file = 'foo.lock';
var counter = 0;

function foo(delay){
    var c = counter ++;

    lockup.lock(file, function (err) {
        setTimeout(function () {
        	console.log('counter', c);
        	
        	// release the lock.
            lockup.unlock(file);
        }, delay);
    });
}

foo(1000);
foo(0); // without `lockup.lock`, "counter 1" will be printed first.

// Then print:
// counter 0
// counter 1