feat: increase time resolution when possible (collectors: os, system, time) (#2047)

internal/collector/filetime/filetime.go

@@ -172,7 +172,7 @@ func (c *Collector) collectGlobFilePath(ch chan<- prometheus.Metric, filePattern
 		ch <- prometheus.MustNewConstMetric(
 			c.fileMTime,
 			prometheus.GaugeValue,
-			float64(fileInfo.ModTime().UTC().Unix()),
+			float64(fileInfo.ModTime().UTC().UnixMicro())/1e6,
 			filePath,
 		)
 	}

internal/collector/logon/logon.go

@@ -96,7 +96,7 @@ func (c *Collector) Collect(ch chan<- prometheus.Metric) error {
 		ch <- prometheus.MustNewConstMetric(
 			c.sessionInfo,
 			prometheus.GaugeValue,
-			float64(session.LogonTime.Unix()),
+			float64(session.LogonTime.UnixMicro())/1e6,
 			session.LogonId.String(), session.UserName, session.LogonDomain, session.LogonType.String(),
 		)
 	}

internal/collector/os/os.go

@@ -290,7 +290,7 @@ func (c *Collector) collectTime(ch chan<- prometheus.Metric) error {
 	ch <- prometheus.MustNewConstMetric(
 		c.time,
 		prometheus.GaugeValue,
-		float64(time.Now().Unix()),
+		float64(time.Now().UnixMicro())/1e6,
 	)
 
 	ch <- prometheus.MustNewConstMetric(

internal/collector/process/process_worker.go

@@ -142,7 +142,7 @@ func (c *Collector) collectWorker() {
 				name, pidString, parentPID, strconv.Itoa(int(processGroupID)), processOwner, cmdLine,
 			)
 
-			startTime := float64(time.Now().Unix() - int64(data.ElapsedTime))
+			startTime := float64(time.Now().UnixMicro())/1e6 - data.ElapsedTime
 
 			ch <- prometheus.MustNewConstMetric(
 				c.startTimeOld,

internal/collector/system/system.go

@@ -141,7 +141,7 @@ func (c *Collector) Build(_ *slog.Logger, _ *mi.Session) error {
 		nil,
 	)
 
-	c.bootTimeTimestamp = float64(time.Now().Unix() - int64(kernel32.GetTickCount64()/1000))
+	c.bootTimeTimestamp = float64(uint64(time.Now().UnixMilli())-kernel32.GetTickCount64()) / 1000
 
 	var err error
 

internal/collector/time/time.go

@@ -245,7 +245,7 @@ func (c *Collector) collectTime(ch chan<- prometheus.Metric) error {
 	ch <- prometheus.MustNewConstMetric(
 		c.currentTime,
 		prometheus.GaugeValue,
-		float64(time.Now().Unix()),
+		float64(time.Now().UnixMicro())/1e6,
 	)
 
 	timeZoneInfo, err := kernel32.GetDynamicTimeZoneInformation()

internal/collector/update/update.go

@@ -405,7 +405,7 @@ func (c *Collector) fetchUpdates(logger *slog.Logger, usd *ole.IDispatch) ([]pro
 	metricsBuf = append(metricsBuf, prometheus.MustNewConstMetric(
 		c.lastScrapeMetric,
 		prometheus.GaugeValue,
-		float64(time.Now().Unix()),
+		float64(time.Now().UnixMicro())/1e6,
 	))
 
 	return metricsBuf, nil