ohld / rated-network-coding-challenge

Rated Network Coding Challenge

Original repo with task description: https://github.com/rated-network/coding-challenge/

Built with FastAPI best practices in mind using FastAPI production template.

Quick start

git clone https://github.com/ohld/rated-network-coding-challenge
cd rated-network-coding-challenge

cp .env.example .env
docker network create app_main
docker-compose up -d --build

# apply migrations to local db
docker compose exec app migrate

# upload sample data
docker compose exec app python ./tests/upload_tx_data.py

I'd suggest to run the latter command separately to let docker image run for a couple seconds. Otherwise phantom errors like Cannot assign requested address for localhost may occur. 🤷

What's inside

GET /stats (src/stats/router.py)

{
  "total_transactions_in_db": 5000,
  "total_gas_used_gwei": 10492553722.431274,
  "total_gas_cost_in_usd": 19219.824439832475
}

POST /transactions (src/transactions/router.py)

Creates transaction in db, returns nothing (for simplicity). Boilerplate to integrate streams further.

1. Stores raw data
2. Calculates gas_used_gwei on the fly
3. Background task to calculate gas_used_usd using Coingecko API (cached with Redis)

GET /transactions/{tx_hash} (src/transactions/router.py)

Returns TransactionCompactResponse:

{
  "hash": "0x06568e8d3c76f6961c650c3b2c9404c79b3bb14138051313b9a74e6255d02140",
  "from_address": "0x7f21c6ab63892ed9db38f5b79d0fadaf4ec79a42",
  "to_address": "0x7a097dbacb237d6b6a047368f43514992510bb79",
  "block_number": 17818510,
  "block_timestamp": "2023-08-01T06:58:35+0000",
  "gas_used_gwei": 399397.655979,
  "gas_used_usd": 0.7305556709464458
}

Tests

1. tx data upload + proper get response with calculated fields (gas_used_gwei, gas_used_usd)
2. txs data upload from csv file + proper /stats response

I didn't test the Coingecko API integration and didn't write fallbacks in case it will not be available at some point.

Local Development

First Build Only

1. cp .env.example .env
2. docker network create app_main
3. docker-compose up -d --build

Linters

Format the code

docker compose exec app format

Migrations

• Create an automatic migration from changes in src/database.py

docker compose exec app makemigrations *migration_name*

• Run migrations

docker compose exec app migrate

• Downgrade migrations

docker compose exec app downgrade -1  # or -2 or base or hash of the migration

Tests

All tests are integrational and require DB connection.

One of the choices I've made is to use default database (postgres), separated from app's app database.

• Using default database makes it easier to run tests in CI/CD environments, since there is no need to setup additional databases
• Tests are run with force_rollback=True, i.e. every transaction made is then reverted

Run tests

docker compose exec app pytest