134 lines
3.1 KiB
Go
134 lines
3.1 KiB
Go
package main
|
|
|
|
import (
|
|
"database/sql"
|
|
"errors"
|
|
"fmt"
|
|
"math"
|
|
"strconv"
|
|
"strings"
|
|
|
|
"github.com/prometheus/client_golang/prometheus"
|
|
"github.com/prometheus/common/log"
|
|
)
|
|
|
|
// Query the pg_settings view containing runtime variables
|
|
func querySettings(ch chan<- prometheus.Metric, db *sql.DB) error {
|
|
log.Debugln("Querying pg_setting view")
|
|
|
|
// pg_settings docs: https://www.postgresql.org/docs/current/static/view-pg-settings.html
|
|
//
|
|
// NOTE: If you add more vartypes here, you must update the supported
|
|
// types in normaliseUnit() below
|
|
query := "SELECT name, setting, COALESCE(unit, ''), short_desc, vartype FROM pg_settings WHERE vartype IN ('bool', 'integer', 'real');"
|
|
|
|
rows, err := db.Query(query)
|
|
if err != nil {
|
|
return errors.New(fmt.Sprintln("Error running query on database: ", namespace, err))
|
|
}
|
|
defer rows.Close() // nolint: errcheck
|
|
|
|
for rows.Next() {
|
|
s := &pgSetting{}
|
|
err = rows.Scan(&s.name, &s.setting, &s.unit, &s.shortDesc, &s.vartype)
|
|
if err != nil {
|
|
return errors.New(fmt.Sprintln("Error retrieving rows:", namespace, err))
|
|
}
|
|
|
|
ch <- s.metric()
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// pgSetting is represents a PostgreSQL runtime variable as returned by the
|
|
// pg_settings view.
|
|
type pgSetting struct {
|
|
name, setting, unit, shortDesc, vartype string
|
|
}
|
|
|
|
func (s *pgSetting) metric() prometheus.Metric {
|
|
var (
|
|
err error
|
|
name = strings.Replace(s.name, ".", "_", -1)
|
|
unit = s.unit // nolint: ineffassign
|
|
shortDesc = s.shortDesc
|
|
subsystem = "settings"
|
|
val float64
|
|
)
|
|
|
|
switch s.vartype {
|
|
case "bool":
|
|
if s.setting == "on" {
|
|
val = 1
|
|
}
|
|
case "integer", "real":
|
|
if val, unit, err = s.normaliseUnit(); err != nil {
|
|
// Panic, since we should recognise all units
|
|
// and don't want to silently exlude metrics
|
|
panic(err)
|
|
}
|
|
|
|
if len(unit) > 0 {
|
|
name = fmt.Sprintf("%s_%s", name, unit)
|
|
shortDesc = fmt.Sprintf("%s [Units converted to %s.]", shortDesc, unit)
|
|
}
|
|
default:
|
|
// Panic because we got a type we didn't ask for
|
|
panic(fmt.Sprintf("Unsupported vartype %q", s.vartype))
|
|
}
|
|
|
|
desc := newDesc(subsystem, name, shortDesc)
|
|
return prometheus.MustNewConstMetric(desc, prometheus.GaugeValue, val)
|
|
}
|
|
|
|
func (s *pgSetting) normaliseUnit() (val float64, unit string, err error) {
|
|
val, err = strconv.ParseFloat(s.setting, 64)
|
|
if err != nil {
|
|
return val, unit, fmt.Errorf("Error converting setting %q value %q to float: %s", s.name, s.setting, err)
|
|
}
|
|
|
|
// Units defined in: https://www.postgresql.org/docs/current/static/config-setting.html
|
|
switch s.unit {
|
|
case "":
|
|
return
|
|
case "ms", "s", "min", "h", "d":
|
|
unit = "seconds"
|
|
case "kB", "MB", "GB", "TB", "8kB", "16MB":
|
|
unit = "bytes"
|
|
default:
|
|
err = fmt.Errorf("Unknown unit for runtime variable: %q", s.unit)
|
|
return
|
|
}
|
|
|
|
// -1 is special, don't modify the value
|
|
if val == -1 {
|
|
return
|
|
}
|
|
|
|
switch s.unit {
|
|
case "ms":
|
|
val /= 1000
|
|
case "min":
|
|
val *= 60
|
|
case "h":
|
|
val *= 60 * 60
|
|
case "d":
|
|
val *= 60 * 60 * 24
|
|
case "kB":
|
|
val *= math.Pow(2, 10)
|
|
case "MB":
|
|
val *= math.Pow(2, 20)
|
|
case "GB":
|
|
val *= math.Pow(2, 30)
|
|
case "TB":
|
|
val *= math.Pow(2, 40)
|
|
case "8kB":
|
|
val *= math.Pow(2, 13)
|
|
case "16MB":
|
|
val *= math.Pow(2, 24)
|
|
}
|
|
|
|
return
|
|
}
|