Fix bug when /proc/net/dev contains unexpected line (#421)

* fix bug when /proc/net/dev contains unexpected line

Signed-off-by: 吴家榜 <14038@chinasws.com>

* modifying netDev.parseLine due to odd interface name

Signed-off-by: 吴家榜 <14038@chinasws.com>

* adding testing case for net device that has colon in its name

Signed-off-by: 吴家榜 <14038@chinasws.com>

Co-authored-by: wujiabang <wujiabang@actionsky.com>
Co-authored-by: 吴家榜 <14038@chinasws.com>

net_dev.go

@@ -87,17 +87,17 @@ func newNetDev(file string) (NetDev, error) {
 // parseLine parses a single line from the /proc/net/dev file. Header lines
 // must be filtered prior to calling this method.
 func (netDev NetDev) parseLine(rawLine string) (*NetDevLine, error) {
-	parts := strings.SplitN(rawLine, ":", 2)
-	if len(parts) != 2 {
+	idx := strings.LastIndex(rawLine, ":")
+	if idx == -1 {
 		return nil, errors.New("invalid net/dev line, missing colon")
 	}
-	fields := strings.Fields(strings.TrimSpace(parts[1]))
+	fields := strings.Fields(strings.TrimSpace(rawLine[idx+1:]))
 
 	var err error
 	line := &NetDevLine{}
 
 	// Interface Name
-	line.Name = strings.TrimSpace(parts[0])
+	line.Name = strings.TrimSpace(rawLine[:idx])
 	if line.Name == "" {
 		return nil, errors.New("invalid net/dev line, empty interface name")
 	}

net_dev_test.go

@@ -14,21 +14,24 @@
 package procfs
 
 import (
+	"fmt"
 	"testing"
 )
 
 func TestNetDevParseLine(t *testing.T) {
-	const rawLine = `  eth0: 1 2 3    4    5     6          7         8 9  10    11    12    13     14       15          16`
-
-	have, err := NetDev{}.parseLine(rawLine)
-	if err != nil {
-		t.Fatal(err)
+	tc := []string{"eth0", "eth0:1"}
+	for i := range tc {
+		rawLine := fmt.Sprintf(`  %v: 1 2 3    4    5     6          7         8 9  10    11    12    13     14       15          16`, tc[i])
+		have, err := NetDev{}.parseLine(rawLine)
+		if err != nil {
+			t.Fatal(err)
+		}
+		want := NetDevLine{tc[i], 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
+		if want != *have {
+			t.Errorf("want %v, have %v", want, have)
+		}
 	}
 
-	want := NetDevLine{"eth0", 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
-	if want != *have {
-		t.Errorf("want %v, have %v", want, have)
-	}
 }
 
 func TestNetDev(t *testing.T) {