Reminder Service

A Notification & Reminder microservice responsible for processing asynchronous events and sending automated email notifications. The service consumes messages from RabbitMQ, stores notification requests, and uses scheduled cron jobs to send emails reliably.

Features

• Email Notification Service
• RabbitMQ Message Consumer
• Event-Driven Architecture
• Scheduled Email Processing
• Automated Reminder System
• MySQL Database Integration
• Sequelize ORM
• Nodemailer Email Service
• Cron Job Scheduling
• Notification Status Tracking

---

Tech Stack

• Node.js
• Express.js
• MySQL
• Sequelize ORM
• RabbitMQ
• amqplib
• Nodemailer
• Node Cron
• dotenv

---

Architecture

Booking Service
        |
        |  (RabbitMQ Event)
        v
Reminder Service
        |
        |---- Store Notification
        |
        |---- Cron Job Scheduler
        |
        |---- Send Email
        |
        v
     MySQL

The service listens to events generated by other microservices, stores notification requests, and periodically processes pending notifications.

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Workflow

Notification Flow

1. Another microservice publishes an event.
2. RabbitMQ forwards the event to Reminder Service.
3. Notification request is stored in the database.
4. Cron Job periodically fetches pending notifications.
5. Email is sent using Nodemailer.
6. Notification status is updated.

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Core Functionalities

Event Consumption

• RabbitMQ Consumer
• Queue Binding
• Event Processing
• Message Parsing

Notification Management

• Create Notification Ticket
• Track Notification Status
• Update Delivery Status
• Store Pending Notifications

Email Service

• Automated Email Sending
• Gmail SMTP Integration
• Scheduled Processing
• Delivery Tracking

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Database Model

NotificationTicket

• id
• subject
• content
• recepientEmail
• status
• notificationTime
• createdAt
• updatedAt

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Installation

Clone the repository:

git clone <repository-url>

Install dependencies:

npm install

Configure environment variables:

PORT=3003

DB_HOST=localhost
DB_USER=root
DB_PASSWORD=password
DB_NAME=notification_db

EMAIL_ID=your_email@gmail.com
EMAIL_PASS=your_app_password

MESSAGE_BROKER_URL=amqp://localhost
EXCHANGE_NAME=BOOKING_EXCHANGE

Run migrations:

npx sequelize-cli db:migrate

Start the server:

npm start

---

Project Structure

src/
│
├── config/
├── controller/
├── services/
├── repository/
├── models/
├── migrations/
├── util/
│   ├── job.js
│   └── messageQueue.js
└── index.js

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Key Concepts Implemented

• Microservices Architecture
• Event-Driven Architecture
• RabbitMQ Messaging
• Asynchronous Processing
• Background Jobs
• Email Automation
• Cron Scheduling
• Notification Systems
• Repository Pattern
• Service Layer Pattern

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Future Improvements

• SMS Notifications
• Push Notifications
• Retry Mechanism
• Dead Letter Queues
• Notification Templates
• Email Queue Prioritization
• Redis Integration
• Docker Deployment

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Author

Developed as a notification microservice for handling asynchronous communication and automated email reminders within a scalable flight booking ecosystem.