github.com/GajanSoorian/parallax-invoicing

Invoicing Web Application

A web app that allows creating, updating, and displaying invoices.

API endpoints

Action	Endpoint
Create	POST /v1/invoice/save
Update	POST /v1/invoice/save
Display	GET /v1/invoice/view/{id}

"v1" is the api version.

Commands to build and run invoice-service application

On a terminal, navigate to the folder "parallax-invoicing", which contains the "makefile" (A wrapper for Go build and run commands) and then run the following commands:

`make deps` : fetch all dependent libraries.

`make test` : Run all unit tests.

`make run`  : Build and run the application.  

Environment variables(host IP, port, DB info) needed for the service are stored in invoice-service/invoice-service.env. For this MVP, an online database has been setup for in https://bit.io/GajanSoorian/invoice_db and the relevant connection information have been set in the invoice-service.env file. I will add the reviewer as collaborator for this Database as well. Usage is intuitive, but please let me know if you have any questions. Any SQL DB should work as long the env file is updated with connection information.

On successful launch of the invoice-service Go application, the following command prompt will be displayed: [GIN-debug] Listening and serving HTTP on :3000

Commands to start angular web application

On a terminal, navigate to the invoice-webapp folder and run the below commands:

` npm install : To install dependencies.

npm run build : Build the project.

npm run test : Run the test cases

npm run start : Run the application.`

Use any browser to open: http://localhost:4200/ Note: This project was built using Angular 14.

Complete versions used: Angular CLI: 14.2.4 , Node: 14.20.1 ,Package Manager: npm 8.19.2

Database

Two empty tables required for this application are already created in https://bit.io/GajanSoorian/invoice_db. Table creation query:

CREATE TABLE IF NOT EXISTS invoices ( invoice_id UUID PRIMARY KEY, invoice_number BIGINT, customer_name VARCHAR ( 50 ), customer_email VARCHAR ( 60 ), due_by TIMESTAMP, total_amount NUMERIC );

CREATE TABLE IF NOT EXISTS items ( item_id UUID, item_name VARCHAR ( 50 ), description VARCHAR ( 200 ), price NUMERIC, PRIMARY KEY(item_id), invoice_id UUID, CONSTRAINT fk_invoice FOREIGN KEY(invoice_id) REFERENCES invoices(invoice_id) );

Invite with admin rights for this DB has been sent to [e-mail]

Corner of hope (did not get to these)

• Integration test cases with mocked Database.
• More frontend test cases.
• Better error handling and error propagation.
• Separate routes for different views for manageable code.
• Dockerize application.
• Create an analytics dashboard page as the login page to: - display customer purchasing pattern to predict future order timelines. - upcoming payments - Identify dip/increase in order requests for items.
• Decouple DB operations with the type of Database present.
• Pagination.

Out of scope

• Login and JWT authorization.
• API security.
• Timeouts, rate limiting and retry strategies.
• Logger functionality.
• Alternate API endpoints- gRPC
• Test suites to better manager similar test cases.
• Integration test cases.
• Support for different unit of cost and conversions.
• Tax logic for items.

Tech stack

• Angular 14
• Go 1.16
• Postgres