wallet-service

About

This project showcases an HTTP service that acts as a Wallet Service in a microservice architecture for a betting platform.

Funds in a wallet can increase (e.g. by winning a bet, depositing money, getting a bonus etc.) or decrease (e.g. by placing a bet, withdrawing money etc.).

This sole responsibility is to store the funds and provide the functionality for manipulating the balance.

The service should be able to gracefully shut down and be performant being a part of critical and time-sensitive workflows.

Running the project

1. Start Pulsar cluster locally:

sudo mkdir -p ./data/zookeeper ./data/bookkeeper
# this step might not be necessary on other than Linux platforms
sudo chown 10000 -R data
docker-compose up -d

2. Start the server locally:

go run cmd/rest-api/main.go

3. Start the background consumer responsible for persisting messages from Pulsar into db:

go run cmd/batch-consumer/main.go

Benchmark using hey:

hey -n 100000 -m POST  -H "Content-Type: application/json" -d '{"amount": 10,"reference":"wonbet-1"}' http://localhost:8081/add-funds/andrei

On my machine last test was at 68456.0562 requests/sec.

Run the tests

go test ./...

Sample requests

For simplicity, user ids are simple strings, like andrei. Amounts are in cents and always a positive value.

Check Health of the Service

curl http://localhost:8081/health

Create a Wallet

Create a wallet with amount 100 cents for user with id andrei:

curl -X POST -H "Content-Type: application/json" -d '{"amount": 100}' http://localhost:8081/wallet/andrei

Query the current state of a wallet

curl http://localhost:8081/wallet/andrei

Add funds to a wallet

Make sure the reference field is unique: A reference contains information about the context in which this amount is added/removed. For example: wonbet-111, witraw-222, where the first part is the event and second it a unique id. I don't do any validation for the format, but good when debugging.

curl -X POST -H "Content-Type: application/json" -d '{"amount": 10,"reference":"wonbet-1"}' http://localhost:8081/add-funds/andrei

Remove funds from wallet

Make sure the reference field is unique:

curl -X POST -H "Content-Type: application/json" -d '{"amount": 50,"reference":"lostbet-2"}' http://localhost:8081/remove-funds/andrei