Payslip Generation and Mail Service

Description

This is a pure nodeJS solution to solution to generate and communicate payslip for every employee. While this is an automated cron job that has been scheduled once a month on the first day of the month at 00.00, this UI is for demonstration purpose to trigger the payslip generation and sending of emails. A live environment for this app can be accessed at Payslip Generator

Technical Contraints

• AWS Free Tier Limit
• MailTrap Free Tier Limit (<500 total emails to be sent and throttled email per second)

Packages Used and Purposes Behind Them

Name	Purpose
csv-parse	parser to convert CSV text input into arrays or objects.
email-templates	send custom email templates for nodeJS
express	nodeJS web application framework
lodash	web development facilitator with ootb utility functions
moment	JS date library for date utility functions
node-cron	task scheduler
nodemailer	facilitates email sending
html-to-text	generates text content from html for nodemailer emails
optimist	parse CLI arguments
pug	template engine for nodeJS
serverless-http	deploy nodeJS code to cloud infrastructure
stream-transform	object transformation for stream data

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How to run:

1. Open terminal and clone this project :

   git clone https://github.com/kebearry/jnj_payroll.git

2. Change directory to this project directory in terminal :

   npm install

   This will install dependencies, including node_modules.

   Once you have done step 1 and 2, you don't have to do it again when you want to run this app.

3. Run the project :

   Two ways to run the project

   Through https://5rd9wixb27.execute-api.ap-southeast-1.amazonaws.com/dev or through invoking through Command Line Interface: node app.js --input sample.csv --output output.csv

   The second method will modify the output.csv in root folder

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How Cloud Deployment Was Done

1. AWS CloudFormation template is created from serverless.yml
2. If a Stack has not yet been created, then it is created with no resources except for an S3 Bucket, which will store zip files of the function code
3. The code of the function(s) is then packaged into zip files.
4. Serverless fetches the hashes for all files of the previous deployment (if any) and compares them against the hashes of the local files
5. Serverless terminates the deployment process if all file hashes are the sam
6. Zip files of functions' code are uploaded to S3 Bucket.
7. The CloudFormation Stack is updated with the new CloudFormation template
8. Each deployment publishes a new version for each function in your service
9. Handler defines what function to execute upon lambda invocation
10. This serverless approach has created a lambda function with respective api gateways and cloudwatch logging mechanism