Wallet System API

This is a simple wallet system backend service that supports the setup of wallets, credit/debit transactions, fetching transactions, and getting wallet details.

Website URL: http://34.100.147.31:3001/

Backend Service URL http://34.100.143.158:3000

MySQL DB Host URL http://34.93.251.75:3306/

Postman collection: import file

Check Explanation video -

• Inside /project info/explanation video.mkv directory
• Download from Github repo

See screenshot -

• Inside /project info/screenshots
• Inside Github repo

Table of Contents

• Prerequisite
• Project Setup
• API Endpoints
  • 1. Setup Wallet
  • 2. Credit/Debit Amount
  • 3. Fetch Transactions
  • 4. Get Wallet Details
• Implementation Details
  • 1. Directory Structure
  • 2. Dependencies
  • 3. SQL Queries
  • 4. Database Configuration
  • 5. Deploying to GKE:

Prerequisite

• Docker
• Gcloud cli & kubectl cli for infrastructure deployment(check infrastructure under dependencies section)

Project Setup

• Clone the repository:

  git clone https://github.com/divya661/wallet-system.git
  cd wallet-system

Backend Setup:

• Open terminal & switch of backend directory
  cd backend

• Install dependencies:
  npm install

• Configure the database: Update the config/default.json file with your database credentials.

• Run the server:
  npm run start

  The server will be running at http://localhost:3000 by default.

Frontend Setup:

• Open terminal & switch of frontend directory
  cd frontend

• Install dependencies:
  npm install

• Run the UI:
  npm run start

  The server will be running at http://localhost:3001 by default

MYSQL setup:

• run below commond in terminal using docker-compose for reacting mysql running inside docker container
  docker compose -f "docker-compose.dev.yaml" up -d --build mysql
• Run below command in new terminal to connect to mysql
  docker exec -it wallet-microservice-mysql-1 mysql -u root -p
• Enter root password: root
• PS: we can update root password for security & its different in mysql deployed on GKE cluster

API Endpoints

1. Setup Wallet

• API Endpoint: /wallet/setup
• Method: POST
• Request Body:

  {
      "balance": 20,
      "name": "Hello world"
  } 

• Response:
  • Status Code: 200
  • Response Body:

      {
          "id": "123456789",
          "balance": 20,
          "transactionId": "4349349843",
          "name": "Hello world",
          "date": "2022-01-12T12:34:56.789Z"
      }

Notes: Requested balance can be a decimal up to 4 precision points (e.g., 20.5612).

2. Credit/Debit Amount

• API Endpoint: /transact/:walletId
• Method: POST
• Request Params:

 walletId: ID of the wallet

• Request Body:

    {
        "amount": 10.5,
        "description": "Recharge"
    }

• Response

  • Status Code: 200
  • Response Body:

  {
     "balance": 30,
     "transactionId": "12283233111"
  }

  Notes:

  • For Credit, the amount will be a positive number. For Debit, it will be a negative number.
  • Amount can be a decimal up to 4 precision points (e.g., 4.1203, 0.321, 1.0045).

3. Fetch Transaction:

• API Endpoint: /transactions?walletId={walletId}&skip={skip}&limit={limit}

• Method: GET

• Query Parameters:

  • walletId: ID of the wallet
  • skip: Number of records to skip (optional, default is 0)
  • limit: Maximum number of records to return (optional, default is 10)

• Response:

  • Status Code: 200
  • Response Body:

[
  {
    "id": "343434",
    "walletId": "123456789",
    "amount": 2.4,
    "balance": 12.4,
    "description": "Recharge",
    "date": "2022-01-12T12:34:56.789Z",
    "type": "CREDIT"
  },
  {
    "id": "544521",
    "walletId": "123456789",
    "amount": 10,
    "balance": 10,
    "description": "Setup",
    "date": "2022-01-11T11:23:45.678Z",
    "type": "CREDIT"
     }
]

Notes: The response includes an array of transactions with properties like _id, walletId, amount, balance, description, date, and type.

4. Get Wallet Details

• API Endpoint: /wallet/:id
• Method: GET
• Params:
  • id: ID of the wallet
• Response:
  • Status Code: 200
  • Response Body:

{
  "id": "123456789",
  "balance": 12.4,
  "name": "Wallet A",
  "date": "2022-01-12T12:34:56.789Z"
}

Implementation Details

1. Directory Structure

/wallet-system
    / backend
        /config
        /src
            /controllers
            /models
            /services
            /routes
            /utils
            /constants
            /errors
            /middleware
            /config
            app.js
        package.json
        dev.Dockerfile
        prod.Dockerfile
    /frontend
      /src
        /components
          /common
            /atoms
            /molecules
        /constants
        /enums
        /services
        /utils
      App.tsx
      /public
      package.json
      dev.Dockerfile
      prod.Dockerfile
    /infra
      backend-deployment.yaml
      frontend-deployment.yaml
      mysql-deployment.yaml
  docker-compose.dev.yaml
  docker-compose.prod.yaml
  README.md

2. Dependencies

Backend

• express: Web framework for Node.js
• sequelize: ORM for SQL databases
• mysql2: MySQL database driver
• body-parser: Middleware to parse JSON requests
• config: Configuration management library for Node.js applications.
• mysql: A Node.js driver for MySQL databases.
• nodemon: Utility that monitors for changes in your Node.js application and automatically restarts the server.
• winston: Logging library for Node.js, offering flexible and extensible logging capabilities.
• yup: JavaScript schema builder for value parsing and validation.
• sequelize-cli: Command-line interface for Sequelize ORM, facilitating database migrations and model generation.

Development Depencies

• eslint: To find & fix common errors in javascript following standard style guide
• husky: To create pre-commit git hook for linting & checking commit msg

Frontend

• react: A JavaScript library for building user interfaces, particularly for single-page applications where UI updates are dynamic.

• @emotion/react Provides a set of utility functions for working with Emotion CSS-in-JS library in React.

• @emotion/styled: A styling library for use with Emotion that allows you to write styled components with tagged template literals.

• axios: promise-based HTTP client for the browser and Node.js, making it easy to send asynchronous HTTP requests.

• express: For create server so to run the build generated

• react-csv: A simple CSV (Comma-Separated Values) parsing and exporting library for React.

• react-dom: Provides DOM-specific methods for React, used for rendering React components into the DOM.

• react-icons: A collection of popular icons as React components, making it easy to include icons in your React projects.

• react-router-dom: Provides routing capabilities for React applications, enabling navigation and handling of URLs.

• react-scripts: A set of scripts and configurations used by Create React App to bootstrap and manage React projects.

-react-table: A lightweight and extensible data grid/table for React, providing features for sorting, filtering, and pagination.

• react-toastify: A toast notification library for React applications, allowing you to display non-intrusive notifications.

Development Depencies

• eslint: To find & fix common errors in javascript following standard style guide
• prettier: To format codebase & have consistent style.
• husky: To create pre-commit git hook for linting & checking commit msg

Infrastructure

• Install gcloud cli - https://cloud.google.com/sdk/docs/install
• Install kubectl cli - https://kubernetes.io/docs/tasks/tools/#kubectl

3. SQL Queries:

• Create database & tables:

CREATE DATABASE IF NOT EXISTS wallet;
USE wallet;

CREATE TABLE IF NOT EXISTS Wallets (
    id INT NOT NULL AUTO_INCREMENT,
    balance DECIMAL(10, 4) NOT NULL DEFAULT 0,
    name VARCHAR(255) NOT NULL,
    transactionId UUID DEFAULT UUID(),
    createdAt DATETIME NOT NULL,
    updatedAt DATETIME NOT NULL,
    PRIMARY KEY (id)
);

CREATE TABLE IF NOT EXISTS Transactions (
    id INT NOT NULL AUTO_INCREMENT,
    amount DECIMAL(10, 4) NOT NULL,
    description VARCHAR(255),
    type ENUM('CREDIT', 'DEBIT') NOT NULL,
    balance DECIMAL(10, 4) NOT NULL,
    createdAt DATETIME NOT NULL,
    walletId INT NOT NULL,
    PRIMARY KEY (id),
    FOREIGN KEY (walletId) REFERENCES Wallet(id)
);

• WalletService.js

-- Inserting a new wallet
INSERT INTO Wallet (balance, name, createdAt, updatedAt)
VALUES (?, ?, NOW(), NOW());

-- Finding a wallet by primary key
SELECT id, balance, name, createdAt, updatedAt
FROM Wallet
WHERE id = ?;

• TransactionService.js:

-- Fetching recent transactions
SELECT id, walletId, amount, balance, description, createdAt, type
FROM Transaction
WHERE walletId = ?
ORDER BY createdAt DESC
LIMIT ? OFFSET ?;

-- Finding a wallet by primary key
SELECT id, balance, name, createdAt, updatedAt
FROM Wallet
WHERE id = ?;

-- Start a transaction
START TRANSACTION;

-- Inserting a new transaction
INSERT INTO Transaction (walletId, amount, description, type, balance, createdAt, updatedAt)
VALUES (?, ?, ?, ?, ?, NOW(), NOW());

-- Committing a transaction
COMMIT;

-- Rolling back a transaction
ROLLBACK;

4. Project Configuration environment-wise

Configure your database connection in either of config/default.json, config/development.json or config/production.json file based on environment usage.

5. Deploying to GKE:

Connecting to cluster using gcloud

• gcloud container clusters get-credentials wallet-cluster-1 --zone asia-south1

Apply the YAML files using kubectl for docker container image deployment in the cluster:

• kubectl apply --validate=true -f mysql-deployment.yaml
• kubectl apply --validate=true -f backend-deployment.yaml
• kubectl apply --validate=true -f frontend-deployment.yaml

Monitor the deployment:

• kubectl get pods -w

Build Docker Images:

• docker build -f ./prod.Dockerfile -t wallet-service:latest .
• docker build -f ./prod.Dockerfile -t wallet-ui:latest .

Tag the docker images for Artifact Registry:

• docker tag wallet-service asia-south1-docker.pkg.dev/maximal-mason-411208/wallet/wallet-service:latest
• docker tag wallet-ui asia-south1-docker.pkg.dev/maximal-mason-411208/wallet/wallet-ui:latest
• docker tag mysql asia-south1-docker.pkg.dev/maximal-mason-411208/wallet/mysql:latest

Push docker images into the GCP Artifact Registry:

• docker push asia-south1-docker.pkg.dev/maximal-mason-411208/wallet/mysql:latest
• docker push asia-south1-docker.pkg.dev/maximal-mason-411208/wallet/wallet-service:latest
• docker push asia-south1-docker.pkg.dev/maximal-mason-411208/wallet/wallet-ui:latest

Other useful commands:

• Get all services running in the cluster with there respective internal & external IP & port, etc
• kubectl get services -n default
• Get all pods info:
• kubectl get pods

NAME                                  READY   STATUS    RESTARTS   AGE
backend-deployment-f75cbb499-xk5zw    1/1     Running   0          2m34s
frontend-deployment-6f5496cf8-ktdqz   1/1     Running   0          13m
mysql-deployment-5df766c588-p4t8n     1/1     Running   0          4h9m

• Watch the logs of the pod:
  kubectl logs <pod_name> -f
• Access mysql:
  mysql -u divya --host 34.93.251.75 --port 3306 -p
  will prompt to enter password: divya