From 22901df6982a0eef32ee3361600e5000646ea90c Mon Sep 17 00:00:00 2001
From: Jonathan Davies <jpds@protonmail.com>
Date: Mon, 13 Nov 2023 15:44:58 +0000
Subject: [PATCH] systemd.go: Added watchdog metrics

Signed-off-by: Jonathan Davies <jpds@protonmail.com>
---
 systemd/systemd.go | 94 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 1 deletion(-)

diff --git a/systemd/systemd.go b/systemd/systemd.go
index 85a9df7..89ff080 100644
--- a/systemd/systemd.go
+++ b/systemd/systemd.go
@@ -17,6 +17,7 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"strconv"
 
 	// Register pprof-over-http handlers
 	_ "net/http/pprof"
@@ -42,6 +43,7 @@ var (
 	systemdUser               = kingpin.Flag("systemd.collector.user", "Connect to the user systemd instance.").Bool()
 	enableRestartsMetrics     = kingpin.Flag("systemd.collector.enable-restart-count", "Enables service restart count metrics. This feature only works with systemd 235 and above.").Bool()
 	enableIPAccountingMetrics = kingpin.Flag("systemd.collector.enable-ip-accounting", "Enables service ip accounting metrics. This feature only works with systemd 235 and above.").Bool()
+	watchdogTimeRE            = regexp.MustCompile(`\d+`)
 )
 
 var unitStatesName = []string{"active", "activating", "deactivating", "inactive", "failed"}
@@ -77,6 +79,9 @@ type Collector struct {
 	ipEgressBytes                 *prometheus.Desc
 	ipIngressPackets              *prometheus.Desc
 	ipEgressPackets               *prometheus.Desc
+	watchdogRuntimeSeconds        *prometheus.Desc
+	watchdogLastPingMonotonic     *prometheus.Desc
+	watchdogLastPingTimestamp     *prometheus.Desc
 
 	unitIncludePattern *regexp.Regexp
 	unitExcludePattern *regexp.Regexp
@@ -186,6 +191,21 @@ func NewCollector(logger log.Logger) (*Collector, error) {
 		"Service unit egress IP accounting in packets.",
 		[]string{"name"}, nil,
 	)
+	watchdogRuntimeSeconds := prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "watchdog_runtime_seconds"),
+		"systemd watchdog runtime seconds",
+		[]string{"device"}, nil,
+	)
+	watchdogLastPingMonotonic := prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "watchdog_last_ping_monotonic_seconds"),
+		"systemd watchdog last ping monotonic seconds",
+		[]string{"device"}, nil,
+	)
+	watchdogLastPingTimestamp := prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "watchdog_last_ping_time_seconds"),
+		"systemd watchdog last ping time seconds",
+		[]string{"device"}, nil,
+	)
 	unitIncludePattern := regexp.MustCompile(fmt.Sprintf("^(?:%s)$", *unitInclude))
 	unitExcludePattern := regexp.MustCompile(fmt.Sprintf("^(?:%s)$", *unitExclude))
 
@@ -215,6 +235,9 @@ func NewCollector(logger log.Logger) (*Collector, error) {
 		ipEgressPackets:               ipEgressPackets,
 		unitIncludePattern:            unitIncludePattern,
 		unitExcludePattern:            unitExcludePattern,
+		watchdogRuntimeSeconds:        watchdogRuntimeSeconds,
+		watchdogLastPingMonotonic:     watchdogLastPingMonotonic,
+		watchdogLastPingTimestamp:     watchdogLastPingTimestamp,
 	}, nil
 }
 
@@ -243,7 +266,9 @@ func (c *Collector) Describe(desc chan<- *prometheus.Desc) {
 	desc <- c.ipEgressBytes
 	desc <- c.ipIngressPackets
 	desc <- c.ipEgressPackets
-
+	desc <- c.watchdogRuntimeSeconds
+	desc <- c.watchdogLastPingMonotonic
+	desc <- c.watchdogLastPingTimestamp
 }
 
 func parseUnitType(unit dbus.UnitStatus) string {
@@ -259,6 +284,11 @@ func (c *Collector) collect(ch chan<- prometheus.Metric) error {
 	}
 	defer conn.Close()
 
+	err = c.collectWatchdogMetrics(conn, ch)
+	if err != nil {
+		level.Debug(c.logger).Log("msg", "Failed to collect watchdog timestamps", "err", err)
+	}
+
 	allUnits, err := conn.ListUnitsContext(c.ctx)
 	if err != nil {
 		return errors.Wrap(err, "could not get list of systemd units from dbus")
@@ -620,3 +650,65 @@ func (c *Collector) filterUnits(units []dbus.UnitStatus, includePattern, exclude
 
 	return filtered
 }
+
+func (c *Collector) collectWatchdogMetrics(conn *dbus.Conn, ch chan<- prometheus.Metric) error {
+	watchdogDevice, err := conn.GetManagerProperty("WatchdogDevice")
+	if err != nil {
+		return err
+	}
+
+	watchdogDeviceString := strings.TrimPrefix(strings.TrimSuffix(watchdogDevice, `"`), `"`)
+
+	if len(watchdogDeviceString) == 0 {
+		level.Debug(c.logger).Log("msg", "No watchdog configured, ignoring metrics")
+		return nil
+	}
+
+	runtimeWatchdogUSecProperty, err := conn.GetManagerProperty("RuntimeWatchdogUSec")
+	if err != nil {
+		return err
+	}
+
+	watchdogLastPingMonotonicProperty, err := conn.GetManagerProperty("WatchdogLastPingTimestampMonotonic")
+	if err != nil {
+		return err
+	}
+
+	watchdogLastPingTimeProperty, err := conn.GetManagerProperty("WatchdogLastPingTimestamp")
+	if err != nil {
+		return err
+	}
+
+	parsedRuntimeWatchdog := watchdogTimeRE.FindString(runtimeWatchdogUSecProperty)
+	parsedWatchdogLastPingMonotonic := watchdogTimeRE.FindString(watchdogLastPingMonotonicProperty)
+	parsedWatchdogLastPingTime := watchdogTimeRE.FindString(watchdogLastPingTimeProperty)
+
+	runtimeWatchdogUSec, err := strconv.ParseFloat(parsedRuntimeWatchdog, 64)
+	if err != nil {
+		return err
+	}
+
+	watchdogLastPingMonotonic, err := strconv.ParseFloat(parsedWatchdogLastPingMonotonic, 64)
+	if err != nil {
+		return err
+	}
+
+	watchdogLastPingTimestamp, err := strconv.ParseFloat(parsedWatchdogLastPingTime, 64)
+	if err != nil {
+		return err
+	}
+
+	ch <- prometheus.MustNewConstMetric(
+		c.watchdogRuntimeSeconds, prometheus.GaugeValue,
+		float64(runtimeWatchdogUSec)/1e6, watchdogDevice)
+
+	ch <- prometheus.MustNewConstMetric(
+		c.watchdogLastPingMonotonic, prometheus.GaugeValue,
+		float64(watchdogLastPingMonotonic)/1e6, watchdogDevice)
+
+	ch <- prometheus.MustNewConstMetric(
+		c.watchdogLastPingTimestamp, prometheus.GaugeValue,
+		float64(watchdogLastPingTimestamp)/1e6, watchdogDevice)
+
+	return nil
+}