User Service Application Demo

Introduction

This project is a demonstration of a user service application, designed to showcase my skills in building a robust API using Ruby on Rails. The application supports the creation and retrieval of user records, integrates with an external account key service, and handles asynchronous tasks using Sidekiq. This project serves as an example of my work.

Project Overview

This project is a user service application that supports the creation and retrieval of user records through two API endpoints:

GET /api/users

POST /api/users

The application is designed to handle new user creation, user record retrieval, and integration with an external account key service. It uses a background job to interact with the account key service, ensuring the main API responses remain fast and reliable.

It started as a Rails 5 application and was upgraded to Rails 7.1. The application uses a PostgreSQL database and Redis for Sidekiq. The application is containerized using Docker and Docker Compose for easy setup and deployment.

Author

Martin Ferrari (dmferrari@gmail.com). April, 2024.

Prerequisites

• Docker and Docker Compose
• Ruby 3.3.0
• Rails 7.1.x

Getting Started

Installation

1. Clone the repository:

   git clone git@github.com:dmferrari/user-service-application-demo.git
   cd user-service-application-demo

2. Define the Environment Variables: Environment variables are managed using the dotenv-rails gem. Define them in a .env file in the project root. There is an .env.example file to guide you.

   POSTGRES_PASSWORD=change_me
   POSTGRES_USER=change_me
   REDIS_URL_SIDEKIQ=redis://localhost:6379/1
   SIDEKIQ_PASSWORD=change_me
   SIDEKIQ_USERNAME=change_me

3. Build and start the Docker containers:

   docker compose up --build

4. Setup the test databases in another terminal: Open another terminal and run the commands below to create the databases and run the migrations.

   docker compose run web bin/rails db:create db:migrate

5. Access the application at http://localhost:3005.

API Endpoints

GET /api/users

• Retrieves all user records, sorted by most recently created first.
• Supports optional query parameters to filter results by email, full_name, and metadata.
• Returns:
  • 200 OK on success.
  • 422 Unprocessable Entity for malformed query parameters.
  • 5xx for server errors.

POST /api/users

• Creates a new user record.
• Accepts email, phone_number, full_name, password, and metadata fields.
• Automatically generates a key field.
• Passwords are hashed with a salt value.
• An external account key service is called asynchronously to generate an account_key.
• Returns:
  • 201 Created on success with the created user JSON object (excluding account_key initially).
  • 422 Unprocessable Entity on validation errors.
  • 5xx for server errors.

JSON Specifications

Create a User

Request:

curl --request POST \
  --url http://localhost:3005/api/users \
  --header 'Content-Type: application/json' \
  --data '{
    "user": {
      "email": "user@example.com",
      "full_name": "John Doe",
      "password": "password",
      "phone_number": "5551235555",
      "metadata": "male, age 32, unemployed, college-educated"
    }
  }'

Response:

{
  "email": "user@example.com",
  "phone_number": "5551235555",
  "full_name": "John Doe",
  "key": "generated_key",
  "account_key": null,
  "metadata": "male, age 32, unemployed, college-educated"
}

Retrieve Users

Request:

curl --request GET --url http://localhost:3005/api/users/

Response:

[
  {
    "email": "user@example.com",
    "phone_number": "5551235555",
    "full_name": "John Doe",
    "key": "generated_key",
    "account_key": "generated_account_key",
    "metadata": "male, age 32, unemployed, college-educated"
  }
]

Asynchronous Account Key Service

The application uses a background job (Sidekiq) to request account_key from an external service asynchronously. If the request fails, it retries a specified number of times. Successful key retrieval updates the user record and notifies the client application via a webhook.

Sequence Diagram

sequenceDiagram
    participant ClientApp
    box Service
        participant ServiceApp
        participant Sidekiq
    end
    participant AccountKeyService
    participant Sentry

    ClientApp->>ServiceApp: POST create with `params`
    activate ServiceApp
    ServiceApp->>ClientApp: (HTTP 201) JSON with user attributes.
    deactivate ServiceApp
    ServiceApp-)Sidekiq: AccountKeyCreateJob.new (Asynchronous)
    activate Sidekiq

    loop While Sidekiq retries
        Sidekiq->>AccountKeyService: POST create `account_key`
        alt If AccountKeyService returns `account_key`
            AccountKeyService->>Sidekiq: JSON with `account_key`
        else
            AccountKeyService->>Sidekiq: Error
            Sidekiq->>Sidekiq: Retry job
        end
    end
    Sidekiq->>ServiceApp: Update `account_key`
    alt When retries are exhausted
        Sidekiq->>Sentry: Report exception
    end
    deactivate Sidekiq
    ServiceApp-)ClientApp: Send webhook with `account_key` (Asynchronous)
    ClientApp->>ClientApp: Incorporates `account_key` into user profile.

Loading

Testing

• RSpec is used for testing the application.
• Test coverage includes models, controllers, and services.
• Ensure 100% coverage for critical components.

Notes

Fix Missing Account Keys

A worker (FixMissingAccountKeysWorker) runs hourly to ensure that all user records have an account_key. Missing keys are requested again, and results are handled as described above.

Password Management

Passwords are handled using the bcrypt gem, ensuring they are stored securely.