https://github.com/marialobillo/fcc-urlshortener

nodejs mongo redis
https://github.com/marialobillo/fcc-urlshortener

api freecodecamp-project javascript mongodb nodejs race-conditions redis

Last synced: about 1 month ago
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nodejs mongo redis

• Host: GitHub
• URL: https://github.com/marialobillo/fcc-urlshortener
• Owner: marialobillo
• Created: 2023-07-07T17:56:48.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-07-27T10:47:57.000Z (over 1 year ago)
• Last Synced: 2024-11-15T21:35:26.365Z (3 months ago)
• Topics: api, freecodecamp-project, javascript, mongodb, nodejs, race-conditions, redis
• Language: JavaScript
• Homepage:
• Size: 133 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# URL Shortener Microservice

This is the boilerplate code for the URL Shortener Microservice project. Instructions for building your project can be found at https://www.freecodecamp.org/learn/back-end-development-and-apis/back-end-development-and-apis-projects/url-shortener-microservice.

## Current Implementation Issues

- We have not written any tests for our application. We could miss some cases and bugs.

- I think we could have several simultaneous requests to our application. This could lead to a race condition.

## Race Condition

Even when Node.js is single-threaded we could have race condition on our project. This is because we are using a database to store our data. The database is not single-threaded. So, we could have several simultaneous requests to our application. This could lead to a race condition.

## Solution 1 - Using Async/Await

First potential solution is forcing the 'second' process to wait until the 'first' process has finished. We can do this using `async/await`.

```javascript

const main = async () => {

    await firstProcess();

    await secondProcess();

    ...

}

```

## Solution 2 - Using Mutex

Another possible solution is using Mutex, which is a synchronization primitive that grants exclusive access to the shared resource to only one process at a time. This means that the second process will wait until the first process has finished.

```javascript

// https://www.nodejsdesignpatterns.com/blog/node-js-race-conditions/

import { Mutex } from 'async-mutex'

const mutex = new Mutex()

async function doingSomethingCritical() {

  const release = await mutex.acquire()

  try {

    // ... do something here

  } finally {

    release()

  }

}

```

Resources:

- [Nodejs Race Conditions by Luciano Mammino](https://www.nodejsdesignpatterns.com/blog/node-js-race-conditions/)

- [async-mutex](https://www.npmjs.com/package/async-mutex)