ayushjainrksh/mongodb-transactions

MongoDB Transactions

A REST API to perform large operations on the mongodb database with flexibility to cancel the operation in between and revert the changes.

Problem

Suppose a user uploads a huge CSV file that is parsed and inserted in mongodb. This upload can take a large amount of time. After initiating the upload, the user realizes that they uploaded the outdated file. Now there is no way to stop that ongoing upload with regular application flow.

Implementation

To interrupt a huge operation safely(such as a large file upload) in mongodb, the application uses mongodb transactions. The transactions provice ACID functionality to the application.

• server.js

  The server.js file holds the main the backend logic. It is responsible to start the server on port 3000 and has various endpoints to aid flexibility. The server.js starts its execution in the main thread and deploys a worker thread when it receives a csv upload request.

• worker.js
  

  The worker.js contains the logic to insert csv data to mongodb database while listening for any interrupt. If the user sends a cancel message to the server, the worker stops the execution of the ongoing query and initiates a rollback operation.

• models/Employee.js
  

  This file contains Employee model used throughout the application to demostrate the functionality.

Note: I've used employee data example as sample data for this application.

Prerequisites

• git
• docker
• docker-compose

Usage

• Clone the repo

  git clone https://github.com/ayushjainrksh/mongodb-transactions.git

• Go to the root directory

  cd mongodb-transactions

• Run docker compose

  docker-compose up --build

Routes

• GET '/ping': Test route

• GET '/employee': To display all employee data

• POST '/employee/createOne': To create a single entry in the application

• POST '/employee/create': To create multiple employees by uploading a csv file of employee data

  

• POST '/employee/create/cancel': To stop the ongoing upload

  

Tech stack

• MongoDB version: 4.4.0
• Node.js : 14.4.0