go-metrics

A set of Go libraries to collect metrics for various infrastructure components and exporting them in Prometheus format.

promdb module

promdb module collects database metrics (sql.DBStats) of database connection pools and expose the metrics in the Prometheus format.

Install

go get github.com/innolight/go-metrics/promdb

Example usage

package main

import (
	"database/sql"
	"log"
	"net/http"

	_ "github.com/lib/pq"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"github.com/innolight/go-metrics/promdb"
)

func main() {
	// Create a database connection pool
	db, err := sql.Open("postgres", "postgres://postgres:postgres@localhost:5432/app?sslmode=disable")
	if err != nil {
		log.Fatal(err)
	}

	// Create a new collector for database named "app_db"
	collector := promdb.NewCollector("app_db", db)

	// Register Prometheus collector
	prometheus.MustRegister(collector)

	// Register the metrics handler
	http.Handle("/metrics", promhttp.Handler())

	// Run the web server
	http.ListenAndServe(":8080", nil)
}

To quickly get metrics from the application above:

curl localhost:8080/metrics | grep db

Exposed Metrics

Name	Type	Description	Labels
db_connections_max_open	Gauge	Maximum number of open connections to the database.	db_name
db_connections_open	Gauge	The number of established connections both in use and idle.	db_name
db_connections_in_use	Gauge	The number of connections currently in use.	db_name
db_connections_idle	Gauge	The number of idle connections.	db_name
db_connections_wait_count	Counter	The total number of connections waited for.	db_name
db_connections_wait_duration_seconds	Counter	The total time blocked waiting for a new connection.	db_name
db_connections_max_idle_closed	Counter	The total number of connections closed due to SetMaxIdleConns.	db_name
db_connections_max_idle_time_closed	Counter	The total number of connections closed due to SetConnMaxIdleTime.	db_name
db_connections_max_lifetime_closed	Counter	The total number of connections closed due to SetConnMaxLifetime.	db_name