Week 03 - Multi-Service Application with Docker Compose

Overview

In Week 03, you will extend the University Course Registration System by introducing a microservices architecture and deploying multiple services using Docker Compose.

Unlike Week 02, which contained a single FastAPI application, this week's solution consists of:

• Student Service (FastAPI)
• Course Service (FastAPI)
• Student Database (PostgreSQL)
• Course Database (PostgreSQL)
• Frontend (React)

Docker Compose will be used to build, configure, network, and run all services using a single command.

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Learning Outcomes

After completing this practical, you should be able to:

• Understand a basic microservices architecture.
• Build and deploy multiple containers using Docker Compose.
• Connect multiple FastAPI services with PostgreSQL databases.
• Configure communication between containers.
• Execute unit tests for backend and frontend applications.
• Verify communication between frontend and backend services.

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Application Architecture

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Setup Instructions

1. Clone the Repository

   git clone https://github.com/sit722-devops/week03.git

2. Navigate to the Project

   cd week03

3. Open the Project

   Open the week03 folder using Visual Studio Code.

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Backend Setup

The Student Service and Course Service each have their own Python environment and dependencies.

Student Service

1. Navigate to the Student Service.

   cd student-service

2. Create a virtual environment.

   # Create the virtual environment
   python -m venv .venv
   
   # Activate the virtual environment
   # On macOS/Linux:
   source ./.venv/bin/activate
   
   # On Windows (Command Prompt):
   # .\.venv\Scripts\activate.bat
   
   # On Windows (PowerShell):
   # .\.venv\Scripts\Activate.ps1

3. Install dependencies.

   pip install -r requirements.txt

4. Deactivate the virtual environment and return to the project root.

   deactivate
   cd ..

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Course Service

1. Navigate to the Course Service.

   cd course-service

2. Create a virtual environment.

   # Create the virtual environment
   python -m venv .venv
   
   # Activate the virtual environment
   # On macOS/Linux:
   source ./.venv/bin/activate
   
   # On Windows (Command Prompt):
   # .\.venv\Scripts\activate.bat
   
   # On Windows (PowerShell):
   # .\.venv\Scripts\Activate.ps1

3. Install dependencies.

   pip install -r requirements.txt

4. Deactivate the virtual environment and return to the project root.

   deactivate
   cd ..

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Frontend Setup

1. Navigate to the frontend.

   cd frontend

2. Install the required Node.js packages.

   npm install

3. Return to the project root.

   cd ..

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Execute Unit Tests

Before deploying the application using Docker Compose, ensure all unit tests pass successfully.

Student Service

cd student-service
pytest --verbose tests
cd ..

NOTE: The Student Service unit tests require a PostgreSQL database named students. If the database does not already exist, create it before running the tests. CREATE DATABASE students; The test suite will automatically create the required database tables if they do not already exist.

Course Service

cd course-service
pytest --verbose tests
cd ..

NOTE: The Course Service unit tests require a PostgreSQL database named courses. If the database does not already exist, create it before running the tests. CREATE DATABASE courses; The test suite will automatically create the required database tables if they do not already exist.

Frontend

cd frontend
npm test
cd ..

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Run the Application Using Docker Compose

From the project root directory, execute:

docker compose build --no-cache

docker compose up -d

NOTE: Depending on your version of Docker, you may need to replace docker compose with docker-compose, such as:

docker-compose build --no-cache

docker-compose up -d

Docker Compose will automatically:

• Build the Student Service image.
• Build the Course Service image.
• Build the Frontend image.
• Create the Student PostgreSQL database container.
• Create the Course PostgreSQL database container.
• Create the Docker network.
• Connect all services together.

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Verify Running Containers

Run following:

docker compose ps

You should see the following containers running:

• frontend
• student-service
• course-service
• student-db
• course-db

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View Container Logs

View logs for all containers.

docker compose logs

View logs for the Student Service.

docker compose logs student-service

View logs for the Course Service.

docker compose logs course-service

View logs for the Frontend.

docker compose logs frontend

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Access the Application

Frontend

http://localhost:5173

Student Service Swagger UI

http://localhost:8001/docs

Course Service Swagger UI

http://localhost:8002/docs

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Verify the Application

Using the frontend:

• Create a new student.
• Verify the student appears in the Students table.
• Create a new course.
• Verify the course appears in the Courses table.

Using Swagger UI:

Student Service

• GET /students
• GET /students/{student_id}
• POST /students

Course Service

• GET /courses
• GET /courses/{course_id}
• POST /courses

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Stop the Application

Stop all running containers.

docker compose down

To also remove the PostgreSQL volumes and start with a fresh database next time, run:

docker compose down -v