metrics

metrics

Import path: github.com/InsideGallery/core/metrics

metrics provides backend-agnostic service instrumentation. Services record counts, gauges, and distributions through a Client; processor packages register concrete exporters by name.

Main APIs

• Config selects processors.
• GetEnvConfig(prefix ...string) reads metrics config, defaulting to the METRICS prefix.
• PrometheusOnly(cfg Config) collapses any enabled config to Prometheus.
• Processor is the exporter interface: Close, Count, Gauge, and Distribution.
• Register, RegisteredProcessors, and Factory manage processor registration.
• New(cfg Config, service string) builds a fanout client.
• Default, SetDefault, and InstallDefault manage the process-wide client.
• NormalizeTags returns a sorted copy of tags; TagSet joins sorted tags with commas.

Usage

package example

import (
	"errors"

	_ "github.com/InsideGallery/core/metrics/all"

	"github.com/InsideGallery/core/metrics"
)

func recordMetric() (err error) {
	cfg, err := metrics.GetEnvConfig()
	if err != nil {
		return err
	}

	client, err := metrics.New(cfg, "api")
	if err != nil {
		return err
	}
	if client == nil {
		return nil
	}

	handle := metrics.InstallDefault(client)
	defer func() {
		err = errors.Join(err, handle.Close())
	}()

	return client.Count("requests_total", 1, []string{"status:ok"})
}

Configuration

GetEnvConfig reads:

• METRICS_PROCESSORS: comma-separated processor names, default prometheus.

Processor names are trimmed, lowercased, de-duplicated, and may be split across comma-separated entries. The values none, off, and disabled disable metrics. Processor-specific environment variables do not select processors; they only configure a processor after it has been selected and registered.

Operational Notes

New returns nil, nil when metrics are disabled. A nil *Client is safe to call and returns nil for Close, Count, Gauge, and Distribution.

Import metrics/all or the specific processor packages before selecting processor names in METRICS_PROCESSORS. Processor call errors are joined and wrapped with the metric operation and name.