From f7dd4f97c77af46fa4204ee20a340fa3fba2b4e0 Mon Sep 17 00:00:00 2001
From: Alexander Blagoev <ablagoev@xs-software.com>
Date: Sat, 29 Apr 2017 18:57:54 +0300
Subject: [PATCH] Improve /proc/net/dev parsing to include all edge cases

---
 net/net_linux.go      |  9 ++++--
 net/net_linux_test.go | 67 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 2 deletions(-)

diff --git a/net/net_linux.go b/net/net_linux.go
index 58c0729..414f278 100644
--- a/net/net_linux.go
+++ b/net/net_linux.go
@@ -32,15 +32,20 @@ func IOCountersByFile(pernic bool, filename string) ([]IOCountersStat, error) {
 		return nil, err
 	}
 
+	parts := make([]string, 2)
+
 	statlen := len(lines) - 1
 
 	ret := make([]IOCountersStat, 0, statlen)
 
 	for _, line := range lines[2:] {
-		parts := strings.SplitN(line, ": ", 2)
-		if len(parts) != 2 {
+		separatorPos := strings.LastIndex(line, ":")
+		if separatorPos == -1 {
 			continue
 		}
+		parts[0] = line[0:separatorPos]
+		parts[1] = line[separatorPos+1:]
+
 		interfaceName := strings.TrimSpace(parts[0])
 		if interfaceName == "" {
 			continue
diff --git a/net/net_linux_test.go b/net/net_linux_test.go
index a881b7a..f87fa72 100644
--- a/net/net_linux_test.go
+++ b/net/net_linux_test.go
@@ -1,7 +1,10 @@
 package net
 
 import (
+	"fmt"
+	"io/ioutil"
 	"os"
+	"strings"
 	"syscall"
 	"testing"
 
@@ -9,6 +12,70 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestIOCountersByFileParsing(t *testing.T) {
+	// Prpare a temporary file, which will be read during the test
+	tmpfile, err := ioutil.TempFile("", "proc_dev_net")
+	defer os.Remove(tmpfile.Name()) // clean up
+
+	assert.Nil(t, err, "Temporary file creation failed: ", err)
+
+	cases := [4][2]string{
+		[2]string{"eth0:   ", "eth1:   "},
+		[2]string{"eth0:0:   ", "eth1:0:   "},
+		[2]string{"eth0:", "eth1:"},
+		[2]string{"eth0:0:", "eth1:0:"},
+	}
+	for _, testCase := range cases {
+		err = tmpfile.Truncate(0)
+		assert.Nil(t, err, "Temporary file truncating problem: ", err)
+
+		// Parse interface name for assertion
+		interface0 := strings.TrimSpace(testCase[0])
+		interface0 = interface0[:len(interface0)-1]
+
+		interface1 := strings.TrimSpace(testCase[1])
+		interface1 = interface1[:len(interface1)-1]
+
+		// Replace the interfaces from the test case
+		proc := []byte(fmt.Sprintf("Inter-|   Receive                                                |  Transmit\n face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed\n  %s1       2    3    4    5     6          7         8        9       10    11    12    13     14       15          16\n    %s100 200    300   400    500     600          700         800 900 1000    1100    1200    1300    1400       1500          1600\n", testCase[0], testCase[1]))
+
+		// Write /proc/net/dev sample output
+		_, err = tmpfile.Write(proc)
+		assert.Nil(t, err, "Temporary file writing failed: ", err)
+
+		counters, err := IOCountersByFile(true, tmpfile.Name())
+
+		assert.Nil(t, err)
+		assert.NotEmpty(t, counters)
+		assert.Equal(t, 2, len(counters))
+		assert.Equal(t, interface0, counters[0].Name)
+		assert.Equal(t, 1, int(counters[0].BytesRecv))
+		assert.Equal(t, 2, int(counters[0].PacketsRecv))
+		assert.Equal(t, 3, int(counters[0].Errin))
+		assert.Equal(t, 4, int(counters[0].Dropin))
+		assert.Equal(t, 5, int(counters[0].Fifoin))
+		assert.Equal(t, 9, int(counters[0].BytesSent))
+		assert.Equal(t, 10, int(counters[0].PacketsSent))
+		assert.Equal(t, 11, int(counters[0].Errout))
+		assert.Equal(t, 12, int(counters[0].Dropout))
+		assert.Equal(t, 13, int(counters[0].Fifoout))
+		assert.Equal(t, interface1, counters[1].Name)
+		assert.Equal(t, 100, int(counters[1].BytesRecv))
+		assert.Equal(t, 200, int(counters[1].PacketsRecv))
+		assert.Equal(t, 300, int(counters[1].Errin))
+		assert.Equal(t, 400, int(counters[1].Dropin))
+		assert.Equal(t, 500, int(counters[1].Fifoin))
+		assert.Equal(t, 900, int(counters[1].BytesSent))
+		assert.Equal(t, 1000, int(counters[1].PacketsSent))
+		assert.Equal(t, 1100, int(counters[1].Errout))
+		assert.Equal(t, 1200, int(counters[1].Dropout))
+		assert.Equal(t, 1300, int(counters[1].Fifoout))
+	}
+
+	err = tmpfile.Close()
+	assert.Nil(t, err, "Temporary file closing failed: ", err)
+}
+
 func TestGetProcInodesAll(t *testing.T) {
 	if os.Getenv("CIRCLECI") == "true" {
 		t.Skip("Skip CI")