worker_threads.locks

History

Stability: 1Experimental

Attributes

LockManager

An instance of a LockManager that can be used to coordinate access to resources that may be shared across multiple threads within the same process. The API mirrors the semantics of the browser LockManager

Lock

History

The Lock interface provides information about a lock that has been granted via locks.request()

lock.name

History

Attributes

string

The name of the lock.

lock.mode

History

Attributes

string

The mode of the lock. Either shared or exclusive.

LockManager

History

The LockManager interface provides methods for requesting and introspecting locks. To obtain a LockManager instance use

import { locks } from 'node:worker_threads';

const { locks } = require('node:worker_threads');

This implementation matches the browser LockManager API.

locks.request

History

locks.request(name, options?, callback): Promise

Attributes

name:string

options:Object

mode?:string

Either 'exclusive' or 'shared'. Default: 'exclusive'.

ifAvailable?:boolean

If true, the request will only be granted if the lock is not already held. If it cannot be granted, callback will be invoked with null instead of a Lock instance. Default: false.

steal?:boolean

If true, any existing locks with the same name are released and the request is granted immediately, pre-empting any queued requests. Default: false.

signal:AbortSignal

that can be used to abort a pending (but not yet granted) lock request.

callback:Function

Invoked once the lock is granted (or immediately with null if ifAvailable is true and the lock is unavailable). The lock is released automatically when the function returns, or—if the function returns a promise—when that promise settles.

Returns:Promise

Resolves once the lock has been released.

import { locks } from 'node:worker_threads';

await locks.request('my_resource', async (lock) => {
  // The lock has been acquired.
});
// The lock has been released here.

JavaScript

const { locks } = require('node:worker_threads');

locks.request('my_resource', async (lock) => {
  // The lock has been acquired.
}).then(() => {
  // The lock has been released here.
});

JavaScript

locks.query

History

locks.query(): Promise

Returns:Promise

Resolves with a LockManagerSnapshot describing the currently held and pending locks for the current process.

import { locks } from 'node:worker_threads';

const snapshot = await locks.query();
for (const lock of snapshot.held) {
  console.log(`held lock: name ${lock.name}, mode ${lock.mode}`);
}
for (const pending of snapshot.pending) {
  console.log(`pending lock: name ${pending.name}, mode ${pending.mode}`);
}

JavaScript

const { locks } = require('node:worker_threads');

locks.query().then((snapshot) => {
  for (const lock of snapshot.held) {
    console.log(`held lock: name ${lock.name}, mode ${lock.mode}`);
  }
  for (const pending of snapshot.pending) {
    console.log(`pending lock: name ${pending.name}, mode ${pending.mode}`);
  }
});

JavaScript