aspire-assignment

The repository provides an application that allows authenticated users to go through a loan application. The assignment covers

• users applying for loan
• admins approving/rejecting loan
• users can submit repayments There are a few assumptions and borders drawn around the applicaiotn in the interest of time and scoping.

Mandatory Features (as requested by assignment provider)

• Customer loans need to approved by Admin
• A loan must have an amount and loan term
• The loan and scheduled payments will have state PENDING
• On Admin approving the loan, the loan state changes from PENDING to APPROVED
• Policy check for cutomers to be able to view their own loan only
• Customer can add a repayment greater or equal to the scheduled repayment
• On repayment, the scheduled repayment state changes to PAID
• If all the scheduled repayments connected to a loan are PAID, automatically the loan also become PAID

Additional Fetures Added

• A JWT based auth management added for customers/admins to signup and login
• Customers are allowed to not only apply for a loan but also modify the tenure, amount and even cancel the loan.
• No installments are generated for a loan unless approved by Admin
• Admins can not only APPROVE but also REJECT a loan
• Admins can list all loans which are in PENDING state to decide which takes priority of approval/rejection
• All loans/installments are tracked when they were created/approved/paid
• Customer can repay an amount equal or more than scheduled payment and the upcoming scheduled payments are adjusted equally.
• Customer can close the loan by making greater payments vs the scheduled payment amount
• API version management put in place for ease of management as product grows

Assumptions

• All loans will be assumed to have weekly payment frequency
• All loans provided are zero-interest loans
• Admins cannot apply for loan using the applicaiton

---

Dependecies

the applicaiton uses postgres connection to manage tables. Use of a psql Docker image or local installation is required

Docker usage

run a docer image for postgres

# docker run --name psql -e POSTGRES_PASSWORD=postgres -p 5432:5432 -d postgres:12-alpine
# docker exec -it psql bash
# psql -h localhost -U postgres
# CREATE DATABASE aspire;
# \l

this should list the newly created database aspire connect to database created and execute the create.sql available in pkg/db/sql/create.sql path

# \c aspire;
# <run contents of> create.sql
# \d

Local Server / Remote Server

connect to the local / remote server using a client like TablePlus, DBeaver, PostgreSQL. execute the following in the SQL editor

CREATE DATABASE aspire;
<run contents of> create.sql

---

Prerequisites

• run the db schema available in pkg/db/sql/create.sql path
• ensure the db details are updated correctly in local.yaml file in releases folder
• keep the local.yaml in the same folder as the executable
• go version 1.22 and above is needed to Build the project
  • clone the project to folder aspire-assignment
  • run command go build -o aspire . for mac/linux
  • run command go build -o aspire.exe . for windows
  • run ./aspire or aspire.exe
  • the console should show a message starting router which means that the app has successfully started
• accesible psql database

---

API Endpoints

The postman collection in releases/aspire-assignment.postman_collection.json will ensure all APIs are documented with relevant tests to sync tokens in collection variables

• GET /health --> health check api. can be used for k8 pod health or circuit breaker
• POST /cred/signup --> signup api. works without any auth
• POST /cred/login --> login api. works without any auth
• POST /v1/loan --> apply loan api. only authenticated customer can reach this
• PUT /v1/loan --> modify loan api. only authenticated customer can reach this
• DELETE /v1/loan --> cancel loan api. only authenticated customer can reach this
• GET /v1/loan/status --> get loan status. only authenticated customer can reach this
• GET /v1/loan/installments --> get loan installments and their status. only authenticated customer can reach this
• POST /v1/loan/repay --> customer scheduled payment api. only authenticated customer can reach this
• GET /v1/admin/applications --> lists pending loans. only authenticated admin can reach this
• POST /v1/admin/update --> approve/reject pending loans. only authenticated admin can reach this

Usage

• Download the relevant executable from releases/macos or releases/windows folder and run
• Download the local.yaml and edit the database connection settings

databases:
  postgres:
    host: 127.0.0.1     #db connection ip
    port: 5432          #db connection port
    user: postgres      #db username
    password: postgres  #db password
    db: aspire          #db name
    sslmode: disable
    connect_timeout: 10

• Run the executable ./aspire(mac) or aspire.exe(windows)
  • the console should show a message starting router which means that the app has successfully started
  • ensure to download the local.yaml and keep it in the same folder as the executable
• Import the Postman collection from releases/aspire-assignment.postman_collection.json
• Signup using /cred/signup and create a username and password as a CUTOMER or ADMIN
• Login using /cred/login and receive a auth token to be used for all loan APIs
• Apply for a loan using /v1/loan
• Check loan status using /v1/loan/status
• Login as an ADMIN and check if loan application is available for approve/reject using /v1/admin/applications
• As an ADMIN, approve the loan using /v1/admin/update
• Login as the initial user and check the loan status using /v1/loan/status
  • If the loan is approved, the loan state will show APPROVED and the installments will show as PENDING in /v1/loan/installments
  • If the loan is rejected, the loan state will show REJECTED and the installments will not show in /v1/loan/installments
• Pay a loan installment using /v1/loan/repay
  • Installment amount less than amount due will not be accepted
  • installment amount greater than amount due will be accepted and the upcoming payments will be recalculated. the same can be observed with /v1/loan/installments after each payment
  • payments mark the scheduled payment as PAID
  • The loan is marked as PAID when the ourstanding amount in /v1/loan/installments response becomes 0
  • If the loan is repayed before scheduled tenure, the remaining payments are marked CANCELLED

---

Happy Usage!