Handle nonexisting bonding_masters file (#569)

* silently ignore nonexisting bonding_masters file

Add an empty fixtures dir without a bonding_masters file to test.

* Moved the check to the Update() method

Dropped the empty test dir.

1 files changed, 7 insertions, 1 deletions

diff --git a/collector/bonding_linux.go b/collector/bonding_linux.go
index 75f865e..fa9714b 100644
--- a/collector/bonding_linux.go
+++ b/collector/bonding_linux.go
@@ -23,6 +23,7 @@ import (
         "strings"
 
         "github.com/prometheus/client_golang/prometheus"
+        "github.com/prometheus/common/log"
 )
 
 type bondingCollector struct {
@@ -52,8 +53,13 @@ func NewBondingCollector() (Collector, error) {
 
 // Update reads and exposes bonding states, implements Collector interface. Caution: This works only on linux.
 func (c *bondingCollector) Update(ch chan<- prometheus.Metric) error {
-        bondingStats, err := readBondingStats(sysFilePath("class/net"))
+        statusfile := sysFilePath("class/net")
+        bondingStats, err := readBondingStats(statusfile)
         if err != nil {
+                if os.IsNotExist(err) {
+                        log.Debugf("Not collecting bonding, file does not exist: %s", statusfile)
+                        return nil
+                }
                 return err
         }
         for master, status := range bondingStats {