Calculator

Calculator provides an easy to use API to evaluate mathematical expressions created with following operators:

1. +
2. -
3. *
4. /
5. (
6. )

For example: This expression 1 + 2 * (9 / 3 - 1) * 2 would evaluate to 9

API Reference

Evaluate mathematical expression

  GET /calculus

Tech Stack

Server: JDK-11, Kotlin, Spring-Boot v2.6, Docker, Gradle

Run Locally

Clone the project

git clone https://github.com/ashish-bhatt-go/calculator

Go to the project directory

cd calculator

Build the project - Make sure you have JDK-11 installed and its path set correctly

./gradlew clean build

Start the server(by default it would start server on port 8080)

./gradlew bootRun

Running Tests

Run the following command from the project's root directory

./gradlew clean build test

Demo/Example

You can access and play with the public API deployed on Heroku here. Below is a sample curl request to evaluate an expression using the deployed public API.

curl --location --request GET 'https://calculus-128.herokuapp.com/calculus?query=MiArIDMgKiAoIDUgLSA2ICogOSAvIDMpICogNCAvIDM='

Deployment

Deploy Locally

You can deploy locally using Docker. Please install it first and make sure Docker daemon is running.

Create a local Docker image

docker build -t calculus .

Run the created Docker image

docker run calculus

Deploy to Production

This project uses GitHub actions to build and test the gradle project. After that it builds a docker image and then deploy to Heroku instance. This is completely an automated process though some manual steps were taken to setup project on Heroku.

Manual steps:

1. Create an account on Heroku, if you don't have one
2. Create a new public Java project
3. Create appropriate secrets in GitHub project e.g. Heroku app name, email and API
4. Use GitHub action to build, push and deploy the docker image to Heroku with the new project that you created

Automated steps in the CI/CD pipeline:

1. Push the code to main branch
2. It would run the pipeline as configured with GitHub actions
3. If all the actions are successful, you could access your latest changes here: https://calculus-128.herokuapp.com using the API as described in the Demo section