Add an exporter for /proc/net/netstat, enabled by default.

This catches things like listen overflows, retransmits
and other things that are very useful for retroactive debugging
thus I think it's justified to have it on by default.

collector/netdev.go

@@ -14,12 +14,12 @@ import (
 )
 
 const (
-	procNetDev        = "/proc/net/dev"
+	procNetDev      = "/proc/net/dev"
-	netStatsSubsystem = "network"
+	netDevSubsystem = "network"
 )
 
 var (
-	netStatsMetrics = map[string]*prometheus.GaugeVec{}
+	netDevMetrics = map[string]*prometheus.GaugeVec{}
 )
 
 type netDevCollector struct {
@@ -40,19 +40,19 @@ func NewNetDevCollector(config Config) (Collector, error) {
 }
 
 func (c *netDevCollector) Update(ch chan<- prometheus.Metric) (err error) {
-	netStats, err := getNetStats()
+	netDev, err := getNetDevStats()
 	if err != nil {
 		return fmt.Errorf("Couldn't get netstats: %s", err)
 	}
-	for direction, devStats := range netStats {
+	for direction, devStats := range netDev {
 		for dev, stats := range devStats {
 			for t, value := range stats {
 				key := direction + "_" + t
-				if _, ok := netStatsMetrics[key]; !ok {
+				if _, ok := netDevMetrics[key]; !ok {
-					netStatsMetrics[key] = prometheus.NewGaugeVec(
+					netDevMetrics[key] = prometheus.NewGaugeVec(
 						prometheus.GaugeOpts{
 							Namespace: Namespace,
-							Subsystem: netStatsSubsystem,
+							Subsystem: netDevSubsystem,
 							Name:      key,
 							Help:      fmt.Sprintf("%s %s from /proc/net/dev.", t, direction),
 						},
@@ -63,29 +63,29 @@ func (c *netDevCollector) Update(ch chan<- prometheus.Metric) (err error) {
 				if err != nil {
 					return fmt.Errorf("Invalid value %s in netstats: %s", value, err)
 				}
-				netStatsMetrics[key].WithLabelValues(dev).Set(v)
+				netDevMetrics[key].WithLabelValues(dev).Set(v)
 			}
 		}
 	}
-	for _, m := range netStatsMetrics {
+	for _, m := range netDevMetrics {
 		m.Collect(ch)
 	}
 	return err
 }
 
-func getNetStats() (map[string]map[string]map[string]string, error) {
+func getNetDevStats() (map[string]map[string]map[string]string, error) {
 	file, err := os.Open(procNetDev)
 	if err != nil {
 		return nil, err
 	}
-	return parseNetStats(file)
+	return parseNetDevStats(file)
 }
 
-func parseNetStats(r io.ReadCloser) (map[string]map[string]map[string]string, error) {
+func parseNetDevStats(r io.ReadCloser) (map[string]map[string]map[string]string, error) {
 	defer r.Close()
-	netStats := map[string]map[string]map[string]string{}
+	netDev := map[string]map[string]map[string]string{}
-	netStats["transmit"] = map[string]map[string]string{}
+	netDev["transmit"] = map[string]map[string]string{}
-	netStats["receive"] = map[string]map[string]string{}
+	netDev["receive"] = map[string]map[string]string{}
 
 	scanner := bufio.NewScanner(r)
 	scanner.Scan() // skip first header
@@ -113,10 +113,10 @@ func parseNetStats(r io.ReadCloser) (map[string]map[string]map[string]string, er
 		if err != nil {
 			return nil, err
 		}
-		netStats["transmit"][dev] = transmit
+		netDev["transmit"][dev] = transmit
-		netStats["receive"][dev] = receive
+		netDev["receive"][dev] = receive
 	}
-	return netStats, nil
+	return netDev, nil
 }
 
 func parseNetDevLine(parts []string, header []string) (map[string]string, error) {

collector/netstat.go

@@ -0,0 +1,102 @@
+// +build !nonetStat
+
+package collector
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	procNetStat       = "/proc/net/netstat"
+	netStatsSubsystem = "netstat"
+)
+
+var (
+	netStatsMetrics = map[string]prometheus.Gauge{}
+)
+
+type netStatCollector struct {
+	config Config
+}
+
+func init() {
+	Factories["netstat"] = NewNetStatCollector
+}
+
+// NewNetStatCollector takes a config struct and returns
+// a new Collector exposing network stats.
+func NewNetStatCollector(config Config) (Collector, error) {
+	c := netStatCollector{
+		config: config,
+	}
+	return &c, nil
+}
+
+func (c *netStatCollector) Update(ch chan<- prometheus.Metric) (err error) {
+	netStats, err := getNetStats()
+	if err != nil {
+		return fmt.Errorf("couldn't get netstats: %s", err)
+	}
+	for protocol, protocolStats := range netStats {
+		for name, value := range protocolStats {
+			key := protocol + "_" + name
+			if _, ok := netStatsMetrics[key]; !ok {
+				netStatsMetrics[key] = prometheus.NewGauge(
+					prometheus.GaugeOpts{
+						Namespace: Namespace,
+						Subsystem: netStatsSubsystem,
+						Name:      key,
+						Help:      fmt.Sprintf("%s %s from /proc/net/netstat.", protocol, name),
+					},
+				)
+			}
+			v, err := strconv.ParseFloat(value, 64)
+			if err != nil {
+				return fmt.Errorf("invalid value %s in netstats: %s", value, err)
+			}
+			netStatsMetrics[key].Set(v)
+		}
+	}
+	for _, m := range netStatsMetrics {
+		m.Collect(ch)
+	}
+	return err
+}
+
+func getNetStats() (map[string]map[string]string, error) {
+	file, err := os.Open(procNetStat)
+	if err != nil {
+		return nil, err
+	}
+	return parseNetStats(file)
+}
+
+func parseNetStats(r io.ReadCloser) (map[string]map[string]string, error) {
+	defer r.Close()
+	netStats := map[string]map[string]string{}
+
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		nameParts := strings.Split(string(scanner.Text()), " ")
+		scanner.Scan()
+		valueParts := strings.Split(string(scanner.Text()), " ")
+		// Remove trailing :.
+		protocol := nameParts[0][:len(nameParts[0])-1]
+		netStats[protocol] = map[string]string{}
+		if len(nameParts) != len(valueParts) {
+			return nil, fmt.Errorf("mismatch field count mismatch in %s: %s",
+				procNetStat, protocol)
+		}
+		for i := 1; i < len(nameParts); i++ {
+			netStats[protocol][nameParts[i]] = valueParts[i]
+		}
+	}
+	return netStats, nil
+}

node_exporter.go

@@ -26,7 +26,7 @@ var (
 	configFile        = flag.String("config", "node_exporter.conf", "config file.")
 	memProfile        = flag.String("memprofile", "", "write memory profile to this file")
 	listeningAddress  = flag.String("listen", ":8080", "address to listen on")
-	enabledCollectors = flag.String("enabledCollectors", "attributes,diskstats,filesystem,loadavg,meminfo,stat,time,netdev", "comma-seperated list of collectors to use")
+	enabledCollectors = flag.String("enabledCollectors", "attributes,diskstats,filesystem,loadavg,meminfo,stat,time,netdev,netstat", "comma-seperated list of collectors to use")
 	printCollectors   = flag.Bool("printCollectors", false, "If true, print available collectors and exit")
 
 	collectorLabelNames = []string{"collector", "result"}