eddie023 / wex-tag

A toy application submitted for XYZ job application. Contains a very opinionated approach to API development using codegen and ORM

opinionated-go-api

A toy application for a random Job Application. See REQUIREMENTS.md. Contains a very opinionated approach to API development in Golang using oapi-codegen for types generation to entgo for ORM framework.

The service exposes APIs to Store a Purchase Transaction and Retrieve a Purchase Transaction in a Specified Countyr's Currency.

API: POST {BASE_URL}/purchase

Request Body: {
    "description": "new description",
    "amount": "100.1223"
}

Response: {
    "amountInUSD": "100.12",
    "date": "2023-12-01T10:58:37.050074Z",
    "description": "new description",
    "id": "c4c1666f-2eda-49c7-99b8-635223f1330a"
}

API: GET {BASE_URL}/purchase/ae90db91-d278-4941-b2b0-92e3b6f666e2?country="United Kingdom"&currency=Pound

Response: {
    "convertedDetails": {
        "amount": "8.26",
        "country": "'United Kingdom",
        "currency": "Pound",
        "exchangeRateDate": "2023-09-30",
        "exchangeRateUsed": "0.816"
    },
    "transactionDetails": {
        "amountInUSD": "10.13",
        "date": "2023-12-01T09:28:12.573092Z",
        "description": "new description",
        "id": "ae90db91-d278-4941-b2b0-92e3b6f666e2"
    }
}

Technical Overview

1. API Specification are described in 'openapi.yaml' file which follows OpenAPI 3.1 standard.
2. API types are autogenerated from 'openapi.yaml' file using oapi-codegen pkg.
3. HTTP service is built using Go Chi Router.
4. File 'pkg/api/transaction.go' contains Handler code for our two APIs
5. Package 'pkg/api/service' contains business logic required for our two APIs
6. Postgres DB is used as persistence layer and is dockerized in the codebase.
7. ent.go is used as ORM framework

Running the application

1. copy .env.example and create .env file with given environment variables.
2. Run "docker compose up" to initiate a postgres instance.
3. Run "make run" command to run a go server
4. Make curl request for new purchase transaction using "make post"
5. Get the transaction Id from output of POST request and use that to make GET request!