Locking for Deno Deploy with TypeScript

How you can use LockDB to help you avoid race conditions in Deno Deploy with TypeScript.

tl;dr; You can try out LockDB for free for 30 days and see if it can help you out!

Deno Deploy is a powerful serverless hosting service that allows you to run JavaScript and TypeScript code at the edge. When deploying applications on Deno Deploy, it's important to consider concurrency and race conditions that may arise when multiple requests are being processed simultaneously. One way to handle this is by using a locking mechanism, such as LockDB, to ensure that critical sections of code are executed atomically.

What is LockDB?

LockDB is a cross-platform tool that provides a simple and efficient way to handle process/event locking and avoid race conditions. It acts as a semaphore, enforcing mutual exclusion and limiting access to a resource when multiple threads or processes are involved. LockDB has packages available for Node.js, Browser, Bun, NPM, and Deno, making it versatile and accessible for different environments.

How LockDB works

LockDB operates on the principle of acquiring and releasing locks. When a lock is acquired, it prevents other processes or threads from accessing the locked resource until it is released. This ensures that only one process can execute the critical section of code at a time, avoiding race conditions and maintaining data integrity.

Acquiring and releasing a lock

To acquire a lock using LockDB, you can use the lock('name') method. The name parameter represents the unique identifier for the lock. Here's an example of acquiring a lock in Deno Deploy with TypeScript:

import LockDB from 'https://deno.land/x/lockdb@0.1.1/mod.ts';

const locker = new LockDB('reports', { apiKey: Deno.env.get('LOCKDB_API_KEY') || '' });

async function processRequest() {
  const lockName = 'sales';

  try {
    await locker.lock(lockName);

    // Critical section of code
    // Perform operations that need to be executed atomically

    // Release the lock
    await locker.unlock(lockName);
  } catch (error) {
    console.error(`Failed to process request: ${error}`);
  }
}

In the example above, the lock(lockName) method is used to acquire the lock named sales. The critical section of code follows, where you can perform operations that need to be executed atomically. Finally, the lock is released using the unlock(lockName) method.

Checking the lock status

You can also check the status of a lock using the check('name') method. This allows you to determine if a lock is currently acquired or available. Here's an example of checking the lock status in Deno Deploy with TypeScript:

import LockDB from 'https://deno.land/x/lockdb@0.1.1/mod.ts';

const locker = new LockDB('reports', { apiKey: Deno.env.get('LOCKDB_API_KEY') || '' });

async function checkLockStatus() {
  const isSalesReportLocked = await locker.check('sales');

  if (isSalesReportLocked) {
    console.log('The lock is currently acquired.');
  } else {
    console.log('The lock is available.');
  }
}

In the example above, the check('sales') method is used to determine if the lock named sales is currently acquired. Based on the result, you can take appropriate actions in your application.

Conclusion

Concurrency and race conditions are important considerations when developing applications for Deno Deploy. By using a locking mechanism like LockDB, you can ensure that critical sections of code are executed atomically, avoiding race conditions and maintaining data integrity. LockDB provides a simple and efficient way to handle process/event locking, making it a valuable tool for Deno Deploy developers.

Remember to acquire locks before entering critical sections of code and release them once the operations are completed. By incorporating LockDB into your Deno Deploy applications, you can enhance the reliability and performance of your serverless functions.

You can get started with a 30-day free trial right now!

Happy coding with Deno Deploy and LockDB!