Handle pg_settings names with '.'

pg_setting.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"math"
 	"strconv"
+	"strings"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -49,7 +50,7 @@ type pgSetting struct {
 func (s *pgSetting) metric() prometheus.Metric {
 	var (
 		err       error
-		name      = s.name
+		name      = strings.Replace(s.name, ".", "_", -1)
 		unit      = s.unit
 		shortDesc = s.shortDesc
 		subsystem = "settings"

pg_setting_test.go

@@ -124,6 +124,22 @@ var fixtures = []fixture{
 		d: "Desc{fqName: \"pg_settings_special_minus_one_value_seconds\", help: \"foo foo foo [Units converted to seconds.]\", constLabels: {}, variableLabels: []}",
 		v: -1,
 	},
+	fixture{
+		p: pgSetting{
+			name:      "rds.rds_superuser_reserved_connections",
+			setting:   "2",
+			unit:      "",
+			shortDesc: "Sets the number of connection slots reserved for rds_superusers.",
+			vartype:   "integer",
+		},
+		n: normalised{
+			val:  2,
+			unit: "",
+			err:  "",
+		},
+		d: "Desc{fqName: \"pg_settings_rds_rds_superuser_reserved_connections\", help: \"Sets the number of connection slots reserved for rds_superusers.\", constLabels: {}, variableLabels: []}",
+		v: 2,
+	},
 	fixture{
 		p: pgSetting{
 			name:      "unknown_unit",