CoinCap Code Challenge

Table Of Contents

1. Introduction
2. Prerequisites
3. Development
   1. Technologies
   2. Entity Relationship Diagram
   3. Installation
4. Usage
   1. Automatic Token Price Updates
   2. Swagger UI
5. License

Introduction

CoinCap Code Challenge is a project developed to address a coding challenge that requires the use of Java 17, Spring Boot 3, an SQL database, and data sourced from CoinCap API.

Prerequisites

• Java 17
• MySQL

Development

Technologies

CoinCap Code Challenge is a Spring Boot application and uses a MySQL database.

Entity Relationship Diagram

The following image shows the Entity Relationship Diagram for the CoinCap Code Challenge application.

Installation

Clone the repository

Make sure that you have the prerequisites installed on your development machine and then clone this repository with the following command:

git clone git@github.com:EnduranceCode/coincap-challenge.git

Set up the database

Create a MySQL database

Login into the MySQL server, replace the {LABEL} in the below command as appropriate and then execute it to create the CoinCap Code Challenge database.

CREATE DATABASE {DATABASE_NAME} CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci;

Label Definition

• {DATABASE_NAME} : The name chosen for the new database;

Create a MySQL user

To create a user for the CoinCap Code Challenge database management, replace the {LABELS} in the below command as appropriate and then execute it.

CREATE USER '{USERNAME}'@'localhost' IDENTIFIED WITH caching_sha2_password BY '{PASSWORD}';

Labels Definition

• {USERNAME} : The new account name in the MySQL Server;
• {PASSWORD} : The password of the new account in the MySQL Server.

Grant privileges to the CoinCap Code Challenge MySQL user

To grant the necessary privileges to the CoinCap Code Challenge database user, replace the {LABELS} in the below command as appropriate and then execute it.

GRANT ALL PRIVILEGES ON {DATABASE_NAME}.* TO '{USERNAME}'@'localhost';

Labels Definition

• {DATABASE_NAME} : The database where the MySQL user will be granted privileges;
• {USERNAME} : The account name in the MySQL Server to whom the privileges will be assigned.

Configure the application's database access

To configure the CoinCap Code Challenge access to the database, take the following steps:

1. Copy the file application-secure-TEMPLATE.yml, located in the resources folder and rename it to application-secure.yaml;
2. Replace the {DATABASE_NAME} placeholder with the CoinCap Code Challenge database name;
3. Replace the {DATABASE_USER} placeholder with the CoinCap Code Challenge database user's username;
4. Replace the {DATABASE_NAME} placeholder with the CoinCap Code Challengedatabase user's password;
5. Delete the comments block, at the top of the file, that contains these instructions;
6. Add the comment 'DO NOT COMMIT THIS FILE!' to the first line of the file.

Manage the application's database migrations

The file DATABASE.md, stored in the folder src/main/resources/db/, documents the process to manage the CoinCap Code Challenge database migrations.

Usage

To run the CoinCap Code Challenge application, execute the following command:

./mvnw spring-boot:run

The application will start and be accessible at the following URL:

http://localhost:8083

As it is out of scope, the CoinCap Code Challenge application doesn't provide any CRUD operations for the User resource.

The CoinCap Code Challenge application exposes the following endpoints:

• GET /v1/users/{userId}/wallets/{walletId} : Retrieves the wallet information for the given user with the specified wallet identifier;
• POST /v1/users/{userId}/wallets/{walletId}/assets : Inserts a new asset into the user's wallet;
• PUT /v1/users/{userId}/wallets/{walletId}/assets/{symbol} : Increments the quantity of a specified asset in the user's wallet;
• POST /v1//v1/wallet-evaluation/ : Evaluates a wallet's performance based on a list of input tokens and their average buy values

An authentication mechanism is out of scope for this project, so the CoinCap Code Challenge application doesn't provide such mechanism. Nonetheless, the application validates if the given user owns the given wallet.

The application database is pre-populated with the following data:

• User : A user with the identifier 1 and the nickname EnduranceCode;
• User : A user with the identifier 2 and the nickname EnduranceTrio;
• Wallet : A wallet with the identifier 1 owned by the user with the identifier 1.
• Wallet : A wallet with the identifier 2 owned by the user with the identifier 2.
• Asset : Two assets, one with the symbol BTC and the other with the symbol ETH belonging to wallet with id 1.
• Asset : Two assets, one with the symbol BTC and the other with the symbol ETH belonging to wallet with id 2.

Automatic Token Price Updates

The CoinCap Code Challenge application includes a @Scheduled job that automatically updates token prices at regular intervals. This job fetches the latest prices from the CoinCap API and updates the database to reflect the current market value.

The update frequency is configurable via the application-secure.yaml file located at src/main/resources/application.yml. The configuration key is app.scheduler.token.update-interval, and the value specifies the interval in milliseconds between updates.

The following YAML snippet shows the default configuration that has an update interval of 30 minutes:

app:
  scheduler:
    token:
      update-interval: 1800000

Swagger UI

The CoinCap Code Challenge application provides a Swagger UI for API documentation and testing. It's available at the following URL:

http://localhost:8083/swagger-ui.html

License

CoinCap Code Challenge is licensed under the terms of MIT License.