Metric - Direct Prometheus Integration Example

Code Source: https://github.com/gogf/examples/tree/main/observability/metric/prometheus

Description

This example demonstrates how to directly integrate Prometheus metrics in GoFrame without using OpenTelemetry. It shows how to:

• Create Prometheus metrics directly
• Register metrics with Prometheus registry
• Expose metrics via HTTP endpoint
• Update metric values dynamically

Structure

- `go.mod`: The Go module file for dependency management
- `go.sum`: The Go module checksums file
- `prometheus.go`: The main application demonstrating direct Prometheus integration

Features

The example showcases the following features:

1. Metric Types

   • Counter: Monotonically increasing value
   • Gauge: Value that can go up and down

2. Metric Operations

   • Metric registration
   • Value updates
   • HTTP exposure
   • Random value generation

3. HTTP Endpoints

   • /: Triggers metric updates
   • /metrics: Exposes Prometheus metrics

Requirements

• Go 1.22 or higher
• Git
• GoFrame
• GoFrame OpenTelemetry Metric

Usage

1. Run the example:

   go run prometheus.go

2. Test the application:

   # Generate some metric values
   curl http://localhost:8000/
   
   # View metrics
   curl http://localhost:8000/metrics

3. Example metrics output:

   # HELP demo_counter A demo counter.
   # TYPE demo_counter counter
   demo_counter 1
   
   # HELP demo_gauge A demo gauge.
   # TYPE demo_gauge gauge
   demo_gauge 42

Implementation Details

The example demonstrates:

1. Direct Prometheus metric creation
2. Manual metric registration
3. HTTP server configuration
4. Dynamic value updates
5. Metric exposure

Notes

• Uses native Prometheus client
• No OpenTelemetry dependency
• Simpler but less feature-rich
• Manual metric management
• Good for basic use cases
• Default port is 8000
• Metrics endpoint at /metrics
• Consider security when exposing metrics
• Random values for demonstration
• Counter only increases
• Gauge can increase or decrease