Isomorphic read/write lock that works in single processes, node clusters and web workers
- 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
import mortice from 'mortice'
import delay from '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
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
import mortice from 'mortice'
import observe from '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
import mortice from 'mortice'
import delay from 'delay'
const mutex = mortice()
let release = await mutex.readLock()
// read something
release()
release = await mutex.writeLock()
// write something
release()
$ npm i mortice
Loading this module through a script tag will make its exports available as Mortice
in the global namespace.
<script src="https://unpkg.com/mortice/dist/index.min.js"></script>
Licensed under either of
- Apache 2.0, (LICENSE-APACHE / http://www.apache.org/licenses/LICENSE-2.0)
- MIT (LICENSE-MIT / http://opensource.org/licenses/MIT)
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.