meghnaaallam / webapp

An Assignment Submission RESTful API deployed on AWS. Below is the link to IaaC repo

Cloud Native Webapp - CSYE 6225

About

RESTful Backend API for an Assignment Submission Portal using Node.js, Express, and Sequelize to perform CRUD operations.

• The app creates users from ./opt/users.csv file. Every user has an email and password as their credentials. Authorization is done using Base64

• Only authorized and authenticated users can access the following endpoints

• GET v1/assignments/ Get Assignment

• GET v1/assignments/:id Get Assignments

• POST v1/assignments/:id Add a new Assignment

• PUT v1/assignments/:id Update Assignment information

• DELETE v1/assignments/:id Delete Assignment information

Users that are not authenticated do not have access to the above endpoints but can access the following end-point

• GET /healthz: Performs a health check, verifying the connection to the database.

• The app uses Packer to build AMI Images on AWS, Pulumi to upload the app to EC2 Instances that has auto-scaling groups set up See Pulumi code here

• statsD to launch the app as soon as the application is deployed to EC2

• I have implemented a small use-case of microservice, where an email will be triggered on successful assignment submission. If the assignment submitted is after the deadline then an unsuccessful submission email is sent.

• The microservice is triggered via Amazon SES (I've configured a topic subscription and written the lambda function code here to publish AWS SNS messages to send emails

• Email service used - Mailgun

• Winston - Winston is used for logging, providing both console and file-based logging

Prerequisites

• git (configured with ssh) [link]
• node [link]
• Postman for API testing [link]
• env file for local Postgres step

How to run? (WebApp)

1. Clone the repository from the Organization

2. Install the following dependencies

      npm install

3. Run the program using this command

    node app.js

How to test? (WebApp)

The test cases are written using Jest and Supertest.

The command to run the tests is :

   npx run test

Building AMI Images using Packer

Create the .pkr.hcl template The custom AMI should have the following features:

NOTE: The builder to be used is amazon-ebs.

OS: Ubuntu 22.04 LTS

Build: built on the default VPC

Device Name: /dev/sda1/

Volume Size: 50GiB

Volume Type: gp2

Have valid provisioners. Pre-installed dependencies using a shell script.

I've written a shell script to install dependencies needed for the app to run on the EC2 instance

Custom AMI creation

To create the custom AMI from the .pkr.hcl template as mentioned above, use the commands given below:

# Installs all packer plugins mentioned in the config template
packer init .

To format the template, use:

packer fmt .

To validate the template, use:

# to validate syntax only
packer validate -syntax-only .
# to validate the template as a whole
packer validate -evaluate-datasources .

To build the custom AMI using packer, use:

packer build <filename>.pkr.hcl

Packer HCL Variables To prevent pushing sensitive details we can have variables in I've used packer variables with the extension .pkrvars.hcl.

If you want to validate your build configuration, you can use the following command:

packer validate -evaluate-datasources --var-file=<variables-file>.pkrvars.hcl <build-config>.pkr.hcl

To use these variables files when creating an image, use the build command as shown:

packer build --var-file=<variables-file>.pkrvars.hcl <build-config>.pkr.hcl

CI/CD

This CI pipeline will run if any changes are committed to the master branch. Once the unit tests pass, the CI pipeline should check the validity of the packer build configuration and build the AMI Image, Configure CloudWatch for logging, Amazon SNS Topic subscription configuration (AWS Credentials should be provisioned to build AMI Images, I made use of Github secrets)

Ideally, when I first developed this application, I've configured the CI/CD pipeline to check the packer validity whenever a PR is raised to the main branch and start building the AMI Images after the PR is merged. But currently, I only have the above setup.