Code On Cloud

Code On Cloud is a powerful backend platform designed to provide features like Coding Problem setting, Creating coding contests and custom input based code execution feature which can be used in contest or normal question submission while in practice.

Features

• Code Execution Server: Deployed on Amazon EC2 for reliable code execution.
• Authentication: Implemented JWT for secure and stateless user authentication.
• Java Technologies: Built with Spring Boot, Spring Security, Spring Data MongoDB, Redis, and Spring AMQP for a robust backend.
• Database : Utilized MongoDB for efficient data storage and retrieval.
• Messaging Queue: Integrated RabbitMQ to handle asynchronous code execution requests in a queue, for system efficiency.
• Real-time Leaderboards: Applied scheduling to dynamically update contest leaderboards during running contests.
• Performance Optimization: Used in-memory caching (Redis) to reduce response latency by nearly 65% for frequent requests.
• Pagination and Sorting: Implemented pagination and sorting to efficiently handle and display large sets of data.
• Global Error Handling: Comprehensive error handling to ensure smooth user experience and easy debugging.

Tech Stack

• Authentication: JWT (JSON Web Token)

• Database: MongoDB, Redis

• Messaging Queue: RabbitMQ

• Server: Amazon EC2

• API Documentation: Swagger with Springfox

• API Testing: Postman

• JSON Processing: Jackson

• Scheduling: Spring Scheduler

• Caching: In-Memory Cache (Redis)

• Pagination and Sorting: Spring Data JPA

Installation

Prerequisites:

• Java 8 or higher
• Maven or Gradle
• MongoDB instance
• Redis instance
• RabbitMQ instance
• Amazon EC2 account

Setup

• Clone the repository:

  git clone https://github.com/manas-0407/Code-On-Cloud.git
  cd code-on-cloud

• Configure the application:

  Update the "application.properties" file with your MongoDB, Redis, RabbitMQ configurations.

  # Mongo Connection -

    spring.application.name= <name>
    spring.data.mongodb.uri= <your_connection_uri>
    spring.data.mongodb.database= <your_db_name>


  # Tomcat Port -

    server.port=8081

  # Redis Connection -

    spring.data.redis.host= <redis_host>
    spring.data.redis.port= <redis_port>
    spring.data.redis.password= <your_connection_password>

  # Rabbit MQ Connection(On code execution remote server) -

    spring.rabbitmq.host=localhost
    spring.rabbitmq.port=5672
    spring.rabbitmq.username=guest
    spring.rabbitmq.password=guest

    rabbitmq.queue.name=myQueue
    rabbitmq.reply.queue.name=myQueue2
    rabbitmq.exchange.name=myExchange
    rabbitmq.routing.key=myRoutingKey
    rabbitmq.reply.routing.key=myRoutingKey

• Build the project::

  mvn clean install

• Run the application:

  mvn spring-boot:run

API Reference

Endpoints under /contest :

• Endpoint to create a contest by an authenticated user

      HTTP method : POST 
      Endpoint : /create
      HTTP request parameters : Request Body

Parameter	Type	Description
Title	string	Contest title
start	date	Start date time of contest
end	date	End date time of contest
question_ids	array	List of questions to be added in contest

• Endpoint to fetch contest page if under time else returns relevant response regarding contest status(Started, Finished)

      HTTP method : GET 
      Endpoint : /{contest_id}
      HTTP request parameters : Path Variable

Parameter	Type	Description
contest_id	string	Id of contest to be fetched

• Endpoint to delete contest if not started yet and requested only by it's author.

      HTTP method : DELETE 
      Endpoint : /{contest_id}/delete
      HTTP request parameters : Path Variable

Parameter	Type	Description
contest_id	string	Id of contest to be fetched

• Return all question of contest if under time.

      HTTP method : GET 
      Endpoint : /{contest_id}/question
      HTTP request parameters : Path Variable

Parameter	Type	Description
contest_id	string	Id of contest to be fetched

• Return question with given question id of contest if contest is running.

      HTTP method : GET 
      Endpoint : /{contest_id}/question/{question_id}
      HTTP request parameters : Path Variable

Parameter	Type	Description
contest_id	string	Id of contest to be fetched
question_id	string	Id of question to be fetched

• Endpoint to submit and execute solution to a particular question from the contest, done on a remote server.

      HTTP method : POST 
      Endpoint : /{contest_id}/question/{question_id}/submit
      HTTP request parameters : Path Variable, Request Body

Parameter	Type	Description
contest_id	string	Id of contest to be fetched
question_id	string	Id of question to be fetched
code	string	Code submitted by participant

• Returns current leaderboard of the contest(Paginated).

      HTTP method : GET 
      Endpoint : /{contest_id}/leaderboard/pageNumber=X&pageSize=Y
      HTTP request parameters : Path Variable, Query Param

Parameter	Type	Description
contest_id	string	Id of contest to be fetched
pageNumber	integer	Index of page to be fetched
pageSize	integer	Number of rows per page

• Return a list of upcoming contest

      HTTP method : GET 
      Endpoint : /upcoming 

• Returns a list of running contest

      HTTP method : GET 
      Endpoint : /running  

Endpoints under /question :

• Endpoint to create a question by an authenticated user.

      HTTP method : POST 
      Endpoint : /create
      HTTP request parameters : Request Body

Parameter	Type	Description
title	string	Question Title
statement	string	Problem Statement
test_input	string	Input to test code
test_output	string	Corresponding Output to test code

• Endpoint to fetch questions which appeared in previous contests and are now public

      HTTP method : GET 
      Endpoint : /all

• Returns current leaderboard of the contest. Accepts query parameter like pageSize to define number of rows per page and pageNumber, index of page to be fetched

      HTTP method : GET 
      Endpoint : /id_search/{question_id}
      HTTP request parameters : Path Variable

Parameter	Type	Description
question_id	string	Id of question to be fetched

Endpoints under /api/auth :

• Endpoint to register a user.

      HTTP method : POST 
      Endpoint : /register
      HTTP request parameters : Request Body

Parameter	Type	Description
username	string	Username
password	string	Password

• Endpoint to login a user. Upon successful login user receives JWT token.

      HTTP method : POST 
      Endpoint : /login
      HTTP request parameters : Request Body

Parameter	Type	Description
username	string	Username
password	string	Password

Endpoints under /user :

• Endpoint to fetch List of questions created by a user

      HTTP method : GET 
      Endpoint : /questions

• Endpoint to fetch List of contests created by a user

      HTTP method : GET 
      Endpoint : /contest

Endpoint for remote code execution server :

• Endpoint to send participant's code for execution. Receives output of code execution as response.

      HTTP method : POST
      Endpoint : /run
      HTTP request parameters : Request Body

Parameter	Type	Description
code	string	Code submitted by participant
input	string	Input for code execution
lang_code	int	Language code for multiple Language support
dateTime	date	Date Time of request

Checkout

• Visit https://github.com/manas-0407/CoC_Server
• Repo for code execution server, currently deployed in AWS.

Screenshots