Counter Service

A simple HTTP service that maintains counters identified by unique URLs.

Requirements

• Docker
• Python 3.12+
• pip

Setup

1. Create a Python virtual environment and activate it:

<!-- validate:step id="setup_venv" -->
python -m venv venv
source venv/bin/activate

2. Install Python dependencies:

<!-- validate:step id="install_deps" depends_on="setup_venv" -->
pip install -r requirements.txt

Running the Service

The service uses Docker to run Redis with persistent storage. Use the provided script to start all services:

<!-- validate:step id="start_services" depends_on="install_deps" background=true validate_port="6379,5000" -->
./start-services.sh

This will:

1. Create a Docker volume for Redis data persistence
2. Start Redis in a Docker container
3. Start the Flask application

To stop all services and clean up, press Ctrl+C or run:

<!-- validate:cleanup -->
./start-services.sh cleanup

Running Tests

The test suite includes integration tests with Redis. To run the tests:

<!-- validate:step id="run_tests" depends_on="install_deps" expected_output="test session starts" -->
pytest -v tests/

The tests will:

• Start a separate Redis container for testing
• Run all test cases including:
  • Basic counter operations
  • Concurrent increment testing
  • Health and status endpoint verification
• Automatically clean up the test container

Usage

Increment Counter

Send a GET request to /counter/<counter_id> to increment the counter:

<!-- validate:step id="test_increment" depends_on="start_services" expected_output="1" -->
curl http://localhost:5000/counter/my-counter

Get Counter Value

To get the current value without incrementing:

<!-- validate:step id="test_value" depends_on="test_increment" expected_output="1" -->
curl http://localhost:5000/counter/my-counter/value

Health Check

Check service health:

<!-- validate:step id="test_health" depends_on="start_services" expected_output="healthy" -->
curl http://localhost:5000/health

Service Status

Get detailed service status:

<!-- validate:step id="test_status" depends_on="start_services" expected_output="redis_connected" -->
curl http://localhost:5000/status

Real-Time Dashboard

View all counters and their values in real-time:

<!-- validate:step id="test_dashboard" depends_on="start_services" validate_url="http://localhost:5000/dashboard" expected_status="200" -->
http://localhost:5000/dashboard

The dashboard provides:

• Live counter values with updates every second
• Total number of counters and increments
• Updates per second monitoring
• Timestamp of last update for each counter
• Sound notifications for counter updates (toggle with 🔔/🔕 button)

Each counter_id creates a unique counter. You can use any string as your counter_id!

Configuration

The service can be configured using environment variables:

• REDIS_HOST: Redis server host (default: localhost)
• REDIS_PORT: Redis server port (default: 6379)

Data Persistence

Counter data is persisted in a Docker volume named redis-counter-data. This ensures your counter values survive container restarts.