Installation:

Install Go (version >= 1.18), Docker Desktop and Make

• https://go.dev/
• https://www.docker.com/products/docker-desktop/
• https://www.gnu.org/software/make/

Setup:

Install Go dependencies:

go mod tidy

Initialize and run postgres Docker container:

make postgres

Create DB and Tables

make createdb createtables

Run:

Run unit tests

make test

Run server:

go run main.go

Sample Curl Requests:

Create two accounts:

curl --location 'localhost:8080/accounts' \
--header 'Content-Type: application/json' \
--data '{
    "account_id": 1,
    "initial_balance": "1.23"
}'
curl --location 'localhost:8080/accounts' \
--header 'Content-Type: application/json' \
--data '{
    "account_id": 2,
    "initial_balance": "4.56"
}'

Create Transaction:

curl --location 'localhost:8080/transactions' \
--header 'Content-Type: application/json' \
--data '{
    "source_account_id":2,
    "destination_account_id": 1,
    "amount": "1"
}'

Get Account:

curl --location 'localhost:8080/accounts/1'

Assumptions:

• All accounts created are cash accounts, balance must be >= 0 (enforced by DB constraint)

• AccountID must be >0 (enforced by binding validation check)

• Tested with up to 100 concurrent transactions between two accounts (store_test.go)

• As an internal transfers system,the server is secure, there is no need to:

  • have a strong database username and password, and encrypt it while it's stored
  • implement authentication or authorization checks
  • encrypt the user data (persisted in docker volume)

• The database is reliable, periodic database snapshots and backups are not implemented

• During server and database maintenance/upgrades, downtime is acceptable