# Docker Multi-Service Notes Application

## 1. Introduction

This project is a multi-container web application deployed using Docker.
It demonstrates how multiple services such as frontend, backend,
database, and file storage can be containerized and orchestrated using
Docker Compose.

The system follows a microservices architecture where each service runs
independently and communicates through a Docker network.

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## 2. Objectives

-   Deploy a complete web application using Docker containers
-   Use multiple services (frontend, backend, database)
-   Enable communication between services
-   Implement persistent storage using Docker volumes
-   Provide scripts for managing the application lifecycle

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## 3. System Architecture

The application consists of the following services:

### 3.1 Frontend (Nginx)

-   Serves static files (HTML, CSS, JavaScript)
-   Provides user interface for interacting with the system

### 3.2 Backend (Node.js + Express)

-   Handles API requests
-   Implements business logic
-   Manages notes and file uploads

### 3.3 MongoDB

-   NoSQL database for storing notes
-   Uses persistent storage

### 3.4 Mongo Express

-   Web interface to view and manage database data

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## 4. Features

-   Create notes
-   Delete notes
-   Upload files
-   List uploaded files
-   Download files
-   Persistent data storage

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## 5. Technologies Used

-   Docker
-   Docker Compose
-   Node.js (Express)
-   MongoDB
-   Nginx
-   HTML, CSS, JavaScript

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## 6. Ports and Services

| Service        | Port | Description     |
|----------------|------|-----------------|
| Frontend       | 8080 | Web interface   |
| Backend        | 3000 | API server      |
| Mongo Express  | 8081 | Database UI     |

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## 7. Database Credentials

The MongoDB database is configured with the following credentials:

- **Username:** admin  
- **Password:** pass  

These credentials are used by Mongo Express to connect to the MongoDB service.

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## 8. Persistent Storage

The application uses Docker volumes:

-   mongo-data → stores database data
-   uploads → stores uploaded files

These ensure that data is not lost when containers restart.

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## 9. Network Requirement (IMPORTANT)

⚠️ This application is hosted on a university virtual machine.

To access the application, you must:

-   Be connected to the **Tuke university network**, OR
-   Use a **Tuke VPN connection**

Without VPN/network access, the application URLs may not be reachable.

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## 10. Application Workflow

1.  User accesses frontend via browser
2.  Frontend sends requests to backend API
3.  Backend processes requests
4.  Backend interacts with MongoDB
5.  MongoDB stores/retrieves data
6.  Mongo Express allows database visualization

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## 11. Scripts

### 11.1 Prepare Application

    ./prepare-app.sh

-   Builds Docker images
-   Creates volumes and network

### 11.2 Start Application

    ./start-app.sh

-   Starts all containers
-   Application available at:
    -   http://147.232.204.210:8080
    -   http://147.232.204.210:8081
    -   http://147.232.204.210:3000
    -   http://147.232.204.210:3000/notes
    

### 11.3 Stop Application

    ./stop-app.sh

-   Stops all containers
-   Data remains intact

### 11.4 Remove Application

    ./remove-app.sh

-   Removes containers, volumes, and images

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## 12. Docker Configuration

The application is configured using docker-compose.yml, where:

-   Each service runs in its own container
-   Services communicate using Docker networking
-   Volumes are used for persistent storage

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## 13. Key Concepts Demonstrated

-   Multi-container Docker architecture
-   Service isolation and communication
-   Persistent storage using volumes
-   RESTful API design
-   Static file serving

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## 14. Conclusion

This project demonstrates how to deploy a scalable web application using
Docker containers. It highlights the importance of modular architecture,
persistent storage, and service communication.

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