LockDB

LockDB is a cross-platform tool you can use to handle process/event locking and avoid race conditions. It is sometimes also known as a semaphore.

There are packages for Node.js/Browser/Bun/NPM, Deno, and you can also use it as a CLI.

It has no dependencies, and is very simple to use, with effectively 3 commands/actions/methods: lock('name'), unlock('name'), and check('name'). It also supports locking/unlocking/checking multiple locks at once.

You can get your apiKey at lockdb.com or connect LockDB to your own server/API.

Usage (package)

Node / Browser / Bun / Npm

You don’t need to install anything with Deno, but here’s how you do it with all others:

npm install --save-exact lockdb
yarn add --exact lockdb
pnpm add --save-exact lockdb

// import LockDB from 'lockdb';
// import LockDB from 'https://deno.land/x/lockdb@0.2.2/mod.ts';
const LockDB = require('lockdb');

const lockName = 'sales';
const locker = new LockDB('reports', { apiKey: 'api-key' });

// Check on a lock (optional)
const isReportLocked = await locker.check(lockName);
console.log(isReportLocked); // Outputs `false`

// Obtain a lock, waiting up to 30 seconds for it
try {
  await locker.lock(lockName);

  // Generate important/intensive report here

  // Unlock a lock, returning if it was locked before
  const wasReportLockedBeforeUnlock = await locker.unlock(lockName);
  console.log(wasReportLockedBeforeUnlock); // Outputs `true`
} catch (error) {
  console.error(`Failed to obtain lock (${lockName}): ${error}`);
}

CLI

You can find binaries for your system in the latest release.

Here’s an example for Linux intel (x86_64), on downloading it with curl and moving it to /usr/local/bin/ so it’s available globally as lockdb:

# Download the binary from the latest release for your system and move it to `/usr/local/bin/`. Here's an example for most Linux OSes:
curl -L https://github.com/BrunoBernardino/lockdb/releases/latest/download/lockdb-linux-intel --output lockdb && chmod +x lockdb && sudo mv lockdb /usr/local/bin/

Then to use it, on any OS:

# Set ENV variables
export LOCKDB_SERVICE_ID="reports"
export LOCKDB_API_KEY="api-key"

# Check on a lock
lockdb check sales
# Outputs `false`

# Obtain a lock, waiting up to 30 seconds for it
lockdb lock sales
# Outputs `true`

# Unlock a lock, returning if it was locked before 
lockdb unlock sales
# Outputs `true`

# Check on multiple locks
lockdb check sales,report,cleanup
# Outputs `false`

Development

Requires deno@1.41.0 (other versions will probably work).

make format
make test

# CLI
deno run --allow-net mock_server.ts
deno run --allow-net --allow-env=LOCKDB_SERVICE_ID,LOCKDB_API_KEY,LOCKDB_SERVER_URL main.ts check sales --server-url="http://127.0.0.1:5678" --service-id="reports" --api-key="api-key"

Publishing

1. Commit (and push) changes.
2. Update VERSION in main.ts.
3. Run make publish VERSION=x.y.z. That will publish to npm and push a new tag, which will build binaries, and a new pre-release with them.