Add network bonding collector

This collector exposes two metrics:

- net_bonding_slaves: configured slaves per bonding interface
- net_bonding_slaves_active: currently active slaves per bonding
  interface

collector/bonding.go

@@ -0,0 +1,93 @@
+// +build !nobonding
+
+package collector
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	sysfsNet = "/sys/class/net"
+)
+
+var (
+	bondingSlaves = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "net_bonding_slaves",
+			Help:      "Number of configured slaves per bonding interface.",
+		}, []string{"master"})
+	bondingSlavesActive = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "net_bonding_slaves_active",
+			Help:      "Number of active slaves per bonding interface.",
+		}, []string{"master"})
+)
+
+type bondingCollector struct{}
+
+func init() {
+	Factories["bonding"] = NewBondingCollector
+}
+
+// NewBondingCollector returns a newly allocated bondingCollector.
+// It exposes the number of configured and active slave of linux bonding interfaces.
+func NewBondingCollector(config Config) (Collector, error) {
+	c := bondingCollector{}
+	if _, err := prometheus.RegisterOrGet(bondingSlaves); err != nil {
+		return nil, err
+	}
+	if _, err := prometheus.RegisterOrGet(bondingSlavesActive); err != nil {
+		return nil, err
+	}
+	return &c, nil
+}
+
+// Update reads and exposes bonding states, implements Collector interface. Caution: This works only on linux.
+func (c *bondingCollector) Update() (int, error) {
+	bondingStats, err := readBondingStats(sysfsNet)
+	if err != nil {
+		return 0, err
+	}
+	updates := 0
+	for master, status := range bondingStats {
+		bondingSlaves.WithLabelValues(master).Set(float64(status[0]))
+		updates++
+		bondingSlavesActive.WithLabelValues(master).Set(float64(status[1]))
+		updates++
+	}
+	return updates, nil
+}
+
+func readBondingStats(root string) (status map[string][2]int, err error) {
+	status = map[string][2]int{}
+	masters, err := ioutil.ReadFile(path.Join(root, "bonding_masters"))
+	if err != nil {
+		return nil, err
+	}
+	for _, master := range strings.Fields(string(masters)) {
+		slaves, err := ioutil.ReadFile(path.Join(root, master, "bonding", "slaves"))
+		if err != nil {
+			return nil, err
+		}
+		sstat := [2]int{0, 0}
+		for _, slave := range strings.Fields(string(slaves)) {
+			state, err := ioutil.ReadFile(path.Join(root, master, fmt.Sprintf("slave_%s", slave), "operstate"))
+			if err != nil {
+				return nil, err
+			}
+			sstat[0]++
+			if strings.TrimSpace(string(state)) == "up" {
+				sstat[1]++
+			}
+		}
+		status[master] = sstat
+	}
+	return status, err
+}

collector/bonding_test.go

@@ -0,0 +1,23 @@
+package collector
+
+import (
+	"testing"
+)
+
+func TestBonding(t *testing.T) {
+	bondingStats, err := readBondingStats("fixtures/bonding")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if bondingStats["bond0"][0] != 0 || bondingStats["bond0"][1] != 0 {
+		t.Fatal("bond0 in unexpected state")
+	}
+
+	t.Logf("int: %v", bondingStats["int"])
+	if bondingStats["int"][0] != 2 || bondingStats["int"][1] != 1 {
+		t.Fatal("int in unexpected state")
+	}
+	if bondingStats["dmz"][0] != 2 || bondingStats["dmz"][1] != 2 {
+		t.Fatal("dmz in unexpected state")
+	}
+}

collector/fixtures/bonding/bonding_masters

@@ -0,0 +1 @@
+bond0 dmz int

collector/fixtures/bonding/dmz/bonding/slaves

@@ -0,0 +1 @@
+eth0 eth4

collector/fixtures/bonding/dmz/slave_eth0/operstate

@@ -0,0 +1 @@
+up

collector/fixtures/bonding/dmz/slave_eth4/operstate

@@ -0,0 +1 @@
+up

collector/fixtures/bonding/int/bonding/slaves

@@ -0,0 +1 @@
+eth5 eth1

collector/fixtures/bonding/int/slave_eth1/operstate

@@ -0,0 +1 @@
+down

collector/fixtures/bonding/int/slave_eth5/operstate

@@ -0,0 +1 @@
+up