source/kernel: add internal helper to get kernel version

Signed-off-by: Mikko Ylinen <mikko.ylinen@intel.com>

source/internal/kernelutils/kernel_kconfig.go

@@ -57,8 +57,7 @@ func ParseKconfig(configPath string) (map[string]string, error) {
 	var err error
 	var searchPaths []string
 
-	unameRaw, err := ioutil.ReadFile("/proc/sys/kernel/osrelease")
-	kVer := strings.TrimSpace(string(unameRaw))
+	kVer, err := GetKernelVersion()
 	if err != nil {
 		searchPaths = []string{
 			"/proc/config.gz",

source/internal/kernelutils/kernel_version.go

@@ -0,0 +1,30 @@
+/*
+Copyright 2018-2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kernelutils
+
+import (
+	"io/ioutil"
+	"strings"
+)
+
+func GetKernelVersion() (string, error) {
+	unameRaw, err := ioutil.ReadFile("/proc/sys/kernel/osrelease")
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(string(unameRaw)), nil
+}

source/kernel/kernel.go

@@ -17,10 +17,8 @@ limitations under the License.
 package kernel
 
 import (
-	"io/ioutil"
 	"log"
 	"regexp"
-	"strings"
 
 	"sigs.k8s.io/node-feature-discovery/source"
 	"sigs.k8s.io/node-feature-discovery/source/internal/kernelutils"
@@ -108,14 +106,11 @@ func (s *Source) Discover() (source.Features, error) {
 func parseVersion() (map[string]string, error) {
 	version := map[string]string{}
 
-	// Open file for reading
-	raw, err := ioutil.ReadFile("/proc/sys/kernel/osrelease")
+	full, err := kernelutils.GetKernelVersion()
 	if err != nil {
 		return nil, err
 	}
 
-	full := strings.TrimSpace(string(raw))
-
 	// Replace forbidden symbols
 	fullRegex := regexp.MustCompile("[^-A-Za-z0-9_.]")
 	full = fullRegex.ReplaceAllString(full, "_")