Move stat_linux to cpu_linux and add cpufreq stats (#548)

collector/stat_linux.go

@@ -16,18 +16,13 @@
 package collector
 
 import (
-	"bufio"
-	"os"
-	"strconv"
-	"strings"
+	"fmt"
+
+	"github.com/prometheus/procfs"
 
 	"github.com/prometheus/client_golang/prometheus"
 )
 
-const (
-	userHz = 100
-)
-
 type statCollector struct {
 	cpu          *prometheus.Desc
 	intr         *prometheus.Desc
@@ -83,80 +78,25 @@ func NewStatCollector() (Collector, error) {
 	}, nil
 }
 
-// Expose kernel and system statistics.
+// Update implements Collector and exposes kernel and system statistics.
 func (c *statCollector) Update(ch chan<- prometheus.Metric) error {
-	file, err := os.Open(procFilePath("stat"))
+	fs, err := procfs.NewFS(*procPath)
+	if err != nil {
+		return fmt.Errorf("failed to open procfs: %v", err)
+	}
+	stats, err := fs.NewStat()
 	if err != nil {
 		return err
 	}
-	defer file.Close()
 
-	scanner := bufio.NewScanner(file)
-	for scanner.Scan() {
-		parts := strings.Fields(scanner.Text())
-		if len(parts) == 0 {
-			continue
-		}
-		switch {
-		case strings.HasPrefix(parts[0], "cpu"):
-			// Export only per-cpu stats, it can be aggregated up in prometheus.
-			if parts[0] == "cpu" {
-				break
-			}
-			// Only some of these may be present, depending on kernel version.
-			cpuFields := []string{"user", "nice", "system", "idle", "iowait", "irq", "softirq", "steal", "guest", "guest_nice"}
-			// OpenVZ guests lack the "guest" CPU field, which needs to be ignored.
-			expectedFieldNum := len(cpuFields) + 1
-			if expectedFieldNum > len(parts) {
-				expectedFieldNum = len(parts)
-			}
-			for i, v := range parts[1:expectedFieldNum] {
-				value, err := strconv.ParseFloat(v, 64)
-				if err != nil {
-					return err
-				}
-				// Convert from ticks to seconds
-				value /= userHz
-				ch <- prometheus.MustNewConstMetric(c.cpu, prometheus.CounterValue, value, parts[0], cpuFields[i])
-			}
-		case parts[0] == "intr":
-			// Only expose the overall number, use the 'interrupts' collector for more detail.
-			value, err := strconv.ParseFloat(parts[1], 64)
-			if err != nil {
-				return err
-			}
-			ch <- prometheus.MustNewConstMetric(c.intr, prometheus.CounterValue, value)
-		case parts[0] == "ctxt":
-			value, err := strconv.ParseFloat(parts[1], 64)
-			if err != nil {
-				return err
-			}
-			ch <- prometheus.MustNewConstMetric(c.ctxt, prometheus.CounterValue, value)
-		case parts[0] == "processes":
-			value, err := strconv.ParseFloat(parts[1], 64)
-			if err != nil {
-				return err
-			}
-			ch <- prometheus.MustNewConstMetric(c.forks, prometheus.CounterValue, value)
-		case parts[0] == "btime":
-			value, err := strconv.ParseFloat(parts[1], 64)
-			if err != nil {
-				return err
-			}
-			ch <- prometheus.MustNewConstMetric(c.btime, prometheus.GaugeValue, value)
-		case parts[0] == "procs_running":
-			value, err := strconv.ParseFloat(parts[1], 64)
-			if err != nil {
-				return err
-			}
-			ch <- prometheus.MustNewConstMetric(c.procsRunning, prometheus.GaugeValue, value)
-		case parts[0] == "procs_blocked":
-			value, err := strconv.ParseFloat(parts[1], 64)
-			if err != nil {
-				return err
-			}
-			ch <- prometheus.MustNewConstMetric(c.procsBlocked, prometheus.GaugeValue, value)
-		}
-	}
-	return scanner.Err()
+	ch <- prometheus.MustNewConstMetric(c.intr, prometheus.CounterValue, float64(stats.IRQTotal))
+	ch <- prometheus.MustNewConstMetric(c.ctxt, prometheus.CounterValue, float64(stats.ContextSwitches))
+	ch <- prometheus.MustNewConstMetric(c.forks, prometheus.CounterValue, float64(stats.ProcessCreated))
+
+	ch <- prometheus.MustNewConstMetric(c.btime, prometheus.GaugeValue, float64(stats.BootTime))
+
+	ch <- prometheus.MustNewConstMetric(c.procsRunning, prometheus.GaugeValue, float64(stats.ProcessesRunning))
+	ch <- prometheus.MustNewConstMetric(c.procsBlocked, prometheus.GaugeValue, float64(stats.ProcessesBlocked))
+
+	return nil
 }