Early init of procfs (#1315)

Minor change to match naming convention in other collectors.

Initialize the proc or sys FS instance once while initializing
each collector instead of re-creating for each metric update.

Signed-off-by: Paul Gier <pgier@redhat.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/collector/netclass_linux.go b/collector/netclass_linux.go
index d70db58..d02ead6 100644
--- a/collector/netclass_linux.go
+++ b/collector/netclass_linux.go
@@ -30,6 +30,7 @@ var (
 )
 
 type netClassCollector struct {
+        fs                    sysfs.FS
         subsystem             string
         ignoredDevicesPattern *regexp.Regexp
         metricDescs           map[string]*prometheus.Desc
@@ -41,8 +42,13 @@ func init() {
 
 // NewNetClassCollector returns a new Collector exposing network class stats.
 func NewNetClassCollector() (Collector, error) {
+        fs, err := sysfs.NewFS(*sysPath)
+        if err != nil {
+                return nil, fmt.Errorf("failed to open sysfs: %v", err)
+        }
         pattern := regexp.MustCompile(*netclassIgnoredDevices)
         return &netClassCollector{
+                fs:                    fs,
                 subsystem:             "network",
                 ignoredDevicesPattern: pattern,
                 metricDescs:           map[string]*prometheus.Desc{},
@@ -50,7 +56,7 @@ func NewNetClassCollector() (Collector, error) {
 }
 
 func (c *netClassCollector) Update(ch chan<- prometheus.Metric) error {
-        netClass, err := getNetClassInfo(c.ignoredDevicesPattern)
+        netClass, err := c.getNetClassInfo()
         if err != nil {
                 return fmt.Errorf("could not get net class info: %s", err)
         }
@@ -162,19 +168,15 @@ func pushMetric(ch chan<- prometheus.Metric, subsystem string, name string, valu
         ch <- prometheus.MustNewConstMetric(fieldDesc, valueType, float64(value), ifaceName)
 }
 
-func getNetClassInfo(ignore *regexp.Regexp) (sysfs.NetClass, error) {
-        fs, err := sysfs.NewFS(*sysPath)
-        if err != nil {
-                return nil, err
-        }
-        netClass, err := fs.NewNetClass()
+func (c *netClassCollector) getNetClassInfo() (sysfs.NetClass, error) {
+        netClass, err := c.fs.NewNetClass()
 
         if err != nil {
                 return netClass, fmt.Errorf("error obtaining net class info: %s", err)
         }
 
         for device := range netClass {
-                if ignore.MatchString(device) {
+                if c.ignoredDevicesPattern.MatchString(device) {
                         delete(netClass, device)
                 }
         }