Fantom-foundation/go-lachesis

package prometheus

import (
    "reflect"
    "strings"

    "github.com/ethereum/go-ethereum/metrics"
    "github.com/prometheus/client_golang/prometheus"
)

var namespace = "lachesis"

// SetNamespace for metrics.
func SetNamespace(s string) {
    namespace = s
}

func convertToPrometheusMetric(name string, m interface{}) (prometheus.Collector, bool) {
    opts := prometheus.Opts{
        Namespace: namespace,
        Name:      prometheusDelims(name),
    }

    var collector prometheus.Collector

    switch metric := m.(type) {

    case metrics.Counter:
        collector = prometheus.NewCounterFunc(prometheus.CounterOpts(opts), func() float64 {
            return float64(metric.Count())
        })

    case metrics.Gauge:
        collector = prometheus.NewGaugeFunc(prometheus.GaugeOpts(opts), func() float64 {
            return float64(metric.Value())
        })

    case metrics.GaugeFloat64:
        collector = prometheus.NewGaugeFunc(prometheus.GaugeOpts(opts), func() float64 {
            return metric.Value()
        })

    case metrics.Healthcheck:
        collector = prometheus.NewGaugeFunc(prometheus.GaugeOpts(opts), func() float64 {
            metric.Check()
            if err := metric.Error(); nil != err {
                return 1
            }
            return 0
        })

    case metrics.Meter:
        collector = NewCollector(opts, metric,
            "rate1m", "rate5m", "rate15m", "rate")

    case metrics.Histogram:
        collector = NewCollector(opts, metric,
            "min", "max", "mean")

    case metrics.Timer, metrics.ResettingTimer:
        collector = NewCollector(opts, metric,
            "min", "max", "mean", "rate1m", "rate5m", "rate15m", "rate")

    default:
        logger.Warn("metric doesn't support prometheus",
            "metric", name,
            "type", reflect.TypeOf(m).String())
        return nil, false
    }

    return collector, true
}

func prometheusDelims(name string) string {
    return strings.ReplaceAll(name, "/", ":")
}