This project demonstrates how to implement a complete observability stack for a Go Gin application using OpenTelemetry, Jaeger, Prometheus, Loki, and Grafana.

• Distributed tracing with OpenTelemetry and Jaeger
• Metrics collection with Prometheus
• Log aggregation with Loki
• Visualization with Grafana
• Complete docker-compose setup for local development
• Auto configurated Grafana datasource and dashboards
• Continuous integration with GitHub Actions

1. Clone this repository
2. Start all services:

docker-compose up -d

3. Generate some traffic:

curl http://localhost:8080/hello

4. Explore the observability stack:
   • View traces in Jaeger UI: http://localhost:16686
   • View metrics in Prometheus: http://localhost:9090
   • View everything in Grafana: http://localhost:3000

The project includes a pre-configured Grafana dashboard that shows:

• Request rates and latencies
• HTTP status code distribution
• Application logs with trace correlation
• Recent traces

Login to Grafana with:

• Username: admin
• Password: admin

The Go application demonstrates:

• OpenTelemetry setup for distributed tracing
• Trace context propagation
• Metrics instrumentation
• JSON structured logging with trace IDs

The application includes unit tests that test the actual implementation:

# Run all tests
go test ./...

# Run tests with verbose output
go test -v ./...

# Run a specific test
go test -run TestHelloEndpoint

The test suite includes:

• Tests for the actual router implementation from main.go
• Testing the /hello endpoint response
• Verification of error handling (404) for non-existent routes
• Integration with the OpenTelemetry tracing setup

Dependencies required for testing:

go get github.com/stretchr/testify/assert

This project uses GitHub Actions for continuous integration. On each push or pull request to the main branch, the workflow:

1. Builds the application
2. Runs all unit tests

The workflow configuration is defined in .github/workflows/test.yml. To view the CI status, check the "Actions" tab in the GitHub repository.

1. Edit main.go to change the application logic or add endpoints
2. Rebuild and restart the application:

docker-compose up -d --build app

• DNS resolution issues: Container names might not resolve properly. Check network configurations in docker-compose.yml.
• Loki connection errors: Verify Loki is running with docker-compose ps loki and check logs with docker-compose logs loki.
• Missing data in Grafana: Ensure your data sources are correctly configured and check time ranges.

Check container status:

docker-compose ps

View logs from a specific service:

docker-compose logs [service-name]

Restart a specific service:

docker-compose restart [service-name]

• OpenTelemetry Documentation
• Jaeger Documentation
• Loki Documentation
• Grafana Documentation