From 107f94d90aa50831025ff2843e2b7cdf3547c741 Mon Sep 17 00:00:00 2001
From: Johannes 'fish' Ziemke <github@freigeist.org>
Date: Mon, 17 Feb 2014 18:36:12 +0100
Subject: [PATCH] Add interrupts metrics

---
 exporter/native_collector.go | 76 +++++++++++++++++++++++++++++++++++-
 1 file changed, 74 insertions(+), 2 deletions(-)

diff --git a/exporter/native_collector.go b/exporter/native_collector.go
index 51c3de74..5c7cd361 100644
--- a/exporter/native_collector.go
+++ b/exporter/native_collector.go
@@ -16,8 +16,9 @@ import (
 )
 
 const (
-	procLoad    = "/proc/loadavg"
-	procMemInfo = "/proc/meminfo"
+	procLoad       = "/proc/loadavg"
+	procMemInfo    = "/proc/meminfo"
+	procInterrupts = "/proc/interrupts"
 )
 
 type nativeCollector struct {
@@ -25,6 +26,7 @@ type nativeCollector struct {
 	attributes prometheus.Gauge
 	lastSeen   prometheus.Gauge
 	memInfo    prometheus.Gauge
+	interrupts prometheus.Counter
 	name       string
 	config     config
 }
@@ -43,6 +45,7 @@ func NewNativeCollector(config config, registry prometheus.Registry) (Collector,
 		attributes: prometheus.NewGauge(),
 		lastSeen:   prometheus.NewGauge(),
 		memInfo:    prometheus.NewGauge(),
+		interrupts: prometheus.NewCounter(),
 	}
 
 	registry.Register(
@@ -73,6 +76,13 @@ func NewNativeCollector(config config, registry prometheus.Registry) (Collector,
 		c.memInfo,
 	)
 
+	registry.Register(
+		"node_interrupts",
+		"node_exporter: interrupt details.",
+		prometheus.NilLabels,
+		c.interrupts,
+	)
+
 	return &c, nil
 }
 
@@ -111,6 +121,27 @@ func (c *nativeCollector) Update() (updates int, err error) {
 		}
 		c.memInfo.Set(map[string]string{"type": k}, fv)
 	}
+
+	interrupts, err := getInterrupts()
+	if err != nil {
+		return updates, fmt.Errorf("Couldn't get interrupts: %s", err)
+	}
+	for name, interrupt := range interrupts {
+		for cpuNo, value := range interrupt.values {
+			updates++
+			fv, err := strconv.ParseFloat(value, 64)
+			if err != nil {
+				return updates, fmt.Errorf("Invalid value in interrupts: %s", err)
+			}
+			labels := map[string]string{
+				"CPU":     strconv.Itoa(cpuNo),
+				"type":    name,
+				"info":    interrupt.info,
+				"devices": interrupt.devices,
+			}
+			c.interrupts.Set(labels, fv)
+		}
+	}
 	return updates, err
 }
 
@@ -202,3 +233,44 @@ func getMemInfo() (map[string]string, error) {
 	return memInfo, nil
 
 }
+
+type interrupt struct {
+	info    string
+	devices string
+	values  []string
+}
+
+func getInterrupts() (map[string]interrupt, error) {
+	interrupts := map[string]interrupt{}
+	fh, err := os.Open(procInterrupts)
+	if err != nil {
+		return nil, err
+	}
+	defer fh.Close()
+	scanner := bufio.NewScanner(fh)
+	if !scanner.Scan() {
+		return nil, fmt.Errorf("%s empty", procInterrupts)
+	}
+	cpuNum := len(strings.Fields(string(scanner.Text()))) // one header per cpu
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		parts := strings.Fields(string(line))
+		if len(parts) < cpuNum+2 { // irq + one column per cpu + details,
+			continue // we ignore ERR and MIS for now
+		}
+		intName := parts[0][:len(parts[0])-1] // remove trailing :
+		intr := interrupt{
+			values: parts[1:cpuNum],
+		}
+
+		if _, err := strconv.Atoi(intName); err == nil { // numeral interrupt
+			intr.info = parts[cpuNum+1]
+			intr.devices = strings.Join(parts[cpuNum+2:], " ")
+		} else {
+			intr.info = strings.Join(parts[cpuNum+1:], " ")
+		}
+		interrupts[intName] = intr
+	}
+	return interrupts, nil
+}