Disbursements

REST API for disbursements service in a e-commerce context

Problem statement

Potentially due to the cost of making higher amount of lower value pay-outs to merchants SeQura incurs - currently the company chooses to do disbursements to merchants on a weekly single-payment-per-merchant basis as opposed to on a per-each-shopper-payment-received basis.

This service targets to provide a capability to aggregate a collection of payments over a period of time to a one bigger disbursement to each merchant.

Set up

Requirements

• Java 17
• Docker Engine 20.10.12
• Docker Compose 1.26.0
• port 8080, 3306 to be free

1. Build

./mvnw clean install

2. Run

Usage

• root resource will be available at http://localhost:8080
• Disbursements resource:

POST /disbursements (async)

{
    "timeFrame":{
        "length":"1week",
        "endingBefore":"2022-01-01"
    }
}

GET /disbursements?timeFrameEndingBefore=2022-01-01&timeFrameLength=1week

Deploy (dev-env)

docker-compose -f disbursements-service/docker-compose.yml up

Destroy (dev-env)

docker-compose -f disbursements-service/docker-compose.yml down

Disbursements query optimization

Problem statement

Aggregating huge amount of payments to calculate disbursement amounts is costly:

• The disbursement query caller (a payment system making actual pay-outs to merchants) might be held for excessive periods of time exposing a call to unnecessary risks of call failures.
• Repeating same operation multiple times puts unnecessary pressure on the production database processing live data.

Technical implementation

All heavy-lifting of calculating these disbursements for merchants is memoized via asynchronous disbursements' creation process initiated via upfront API call. This process is backed by a stored procedure in the database which aggregates currently completed orders to a requested weekly disbursements for merchants.

Only after this asynchronous process completes, API provides a way to query weekly disbursements for that particular week. Otherwise, the query request is rejected.

To Do

• Old Orders & Merchants data migration is not done.
• Disbursements query for a specific merchant is not done.
• API to capture live completed-orders flow is not done
• Onboarding API for merchants created in SeQura after initial data migration - is not done.
• Errors are expressed only as http error codes
• Logging, Security, Other important non-functional requirements for services going live - not done.