How is metrics collection and processing carried out in the system?

In Go systems, metrics collection and processing are usually implemented using specialized libraries, such as the Prometheus client.

Main steps:

1. Metrics collection — counters, histograms, timers, and other metrics are created in the code and updated during operations.
2. Metrics exposition — an HTTP server is started, which serves the current metric values at a specific endpoint (e.g., /metrics) in a format understandable by the monitoring system.
3. Metrics processing — an external monitoring system (Prometheus) periodically polls the endpoint and collects data for visualization and alerting.

Example with Prometheus client:

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

var opsProcessed = prometheus.NewCounter(prometheus.CounterOpts{
    Name: "myapp_processed_ops_total",
    Help: "The total number of processed events",
})

func init() {
    prometheus.MustRegister(opsProcessed)
}

func main() {
    http.Handle("/metrics", promhttp.Handler())
    go http.ListenAndServe(":2112", nil)

    // Increment the counter in the code
    opsProcessed.Inc()
}