collector/systemd: add new label "type" for systemd_unit_state (#1229)

Adds a new label called "type" systemd_unit_state which contains the
Type field from the unit file.  This applies only to the .service and
.mount unit types.  The other unit types do not include the optional
type field.

Fixes #1210

Signed-off-by: Paul Gier <pgier@redhat.com>

collector/systemd_linux.go

@@ -17,14 +17,14 @@ package collector
 
 import (
 	"fmt"
+	"math"
 	"regexp"
 	"strings"
 
 	"github.com/coreos/go-systemd/dbus"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
-	"gopkg.in/alecthomas/kingpin.v2"
-	"math"
+	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
 var (
@@ -61,7 +61,7 @@ func NewSystemdCollector() (Collector, error) {
 
 	unitDesc := prometheus.NewDesc(
 		prometheus.BuildFQName(namespace, subsystem, "unit_state"),
-		"Systemd unit", []string{"name", "state"}, nil,
+		"Systemd unit", []string{"name", "state", "type"}, nil,
 	)
 	unitStartTimeDesc := prometheus.NewDesc(
 		prometheus.BuildFQName(namespace, subsystem, "unit_start_time_seconds"),
@@ -153,7 +153,7 @@ func (c *systemdCollector) collectUnitStatusMetrics(ch chan<- prometheus.Metric,
 			}
 			ch <- prometheus.MustNewConstMetric(
 				c.unitDesc, prometheus.GaugeValue, isActive,
-				unit.Name, stateName)
+				unit.Name, stateName, unit.serviceType)
 		}
 		if strings.HasSuffix(unit.Name, ".service") && unit.nRestarts != nil {
 			ch <- prometheus.MustNewConstMetric(
@@ -252,11 +252,22 @@ type unit struct {
 	tasksCurrent        *uint64
 	tasksMax            *uint64
 	nRestarts           *uint32
+	serviceType         string
 	acceptedConnections uint32
 	currentConnections  uint32
 	refusedConnections  *uint32
 }
 
+// unitType gets the suffix after the last "." in the
+// unit name and capitalizes the first letter
+func (u *unit) unitType() string {
+	suffixIndex := strings.LastIndex(u.Name, ".") + 1
+	if suffixIndex < 1 || suffixIndex > len(u.Name) {
+		return ""
+	}
+	return strings.Title(u.Name[suffixIndex:])
+}
+
 func (c *systemdCollector) getAllUnits() ([]unit, error) {
 	conn, err := c.newDbus()
 	if err != nil {
@@ -276,7 +287,15 @@ func (c *systemdCollector) getAllUnits() ([]unit, error) {
 		unit := unit{
 			UnitStatus: status,
 		}
-
+		unitType := unit.unitType()
+		if unitType == "Service" || unitType == "Mount" {
+			serviceType, err := conn.GetUnitTypeProperty(unit.Name, unitType, "Type")
+			if err != nil {
+				log.Debugf("couldn't get type for unit '%s': %s", unit.Name, err)
+			} else {
+				unit.serviceType = serviceType.Value.Value().(string)
+			}
+		}
 		if strings.HasSuffix(unit.Name, ".timer") {
 			lastTriggerValue, err := conn.GetUnitTypeProperty(unit.Name, "Timer", "LastTriggerUSec")
 			if err != nil {