Move version information into a separate module

Dockerfile

@@ -10,7 +10,7 @@ ARG NFD_VERSION
 RUN go get github.com/golang/dep/cmd/dep
 RUN dep ensure
 RUN go install \
-  -ldflags "-s -w -X main.version=$NFD_VERSION" \
+  -ldflags "-s -w -X sigs.k8s.io/node-feature-discovery/pkg/version.version=$NFD_VERSION" \
   sigs.k8s.io/node-feature-discovery
 RUN install -D -m644 node-feature-discovery.conf.example /etc/kubernetes/node-feature-discovery/node-feature-discovery.conf
 

main.go

@@ -17,6 +17,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/validation"
 	k8sclient "k8s.io/client-go/kubernetes"
 	restclient "k8s.io/client-go/rest"
+	"sigs.k8s.io/node-feature-discovery/pkg/version"
 	"sigs.k8s.io/node-feature-discovery/source"
 	"sigs.k8s.io/node-feature-discovery/source/cpu"
 	"sigs.k8s.io/node-feature-discovery/source/cpuid"
@@ -48,10 +49,6 @@ const (
 	NodeNameEnv = "NODE_NAME"
 )
 
-var (
-	version = "" // Must not be const, set using ldflags at build time
-)
-
 // package loggers
 var (
 	stdoutLogger = log.New(os.Stdout, "", log.LstdFlags)
@@ -115,10 +112,10 @@ type Args struct {
 
 func main() {
 	// Assert that the version is known
-	if version == "" {
-		stderrLogger.Fatalf("main.version not set! Set -ldflags \"-X main.version `git describe --tags --dirty --always`\" during build or run.")
+	if version.Get() == "undefined" {
+		stderrLogger.Fatalf("version not set! Set -ldflags \"-X sigs.k8s.io/node-feature-discovery/pkg/version.version=`git describe --tags --dirty --always`\" during build or run.")
 	}
-	stdoutLogger.Printf("Node Feature Discovery %s", version)
+	stdoutLogger.Printf("Node Feature Discovery %s", version.Get())
 
 	// Parse command-line arguments.
 	args := argsParse(nil)
@@ -199,7 +196,7 @@ func argsParse(argv []string) (args Args) {
 	)
 
 	arguments, _ := docopt.Parse(usage, argv, true,
-		fmt.Sprintf("%s %s", ProgramName, version), false)
+		fmt.Sprintf("%s %s", ProgramName, version.Get()), false)
 
 	// Parse argument values as usable types.
 	var err error
@@ -332,7 +329,7 @@ func updateNodeWithFeatureLabels(helper APIHelpers, noPublish bool, labels Label
 			keys = append(keys, k)
 		}
 		sort.Strings(keys)
-		annotations := Annotations{"version": version,
+		annotations := Annotations{"version": version.Get(),
 			"feature-labels": strings.Join(keys, ",")}
 
 		err := advertiseFeatureLabels(helper, labels, annotations)

main_test.go

@@ -17,6 +17,7 @@ import (
 	"sigs.k8s.io/node-feature-discovery/source"
 	"sigs.k8s.io/node-feature-discovery/source/fake"
 	"sigs.k8s.io/node-feature-discovery/source/panic_fake"
+	"sigs.k8s.io/node-feature-discovery/pkg/version"
 )
 
 func TestDiscoveryWithMockSources(t *testing.T) {
@@ -26,7 +27,7 @@ func TestDiscoveryWithMockSources(t *testing.T) {
 		fakeFeatureNames := []string{"testfeature1", "testfeature2", "testfeature3"}
 		fakeFeatures := source.Features{}
 		fakeFeatureLabels := Labels{}
-		fakeAnnotations := Annotations{"version": version,
+		fakeAnnotations := Annotations{"version": version.Get(),
 			"feature-labels": "testSource-testfeature1,testSource-testfeature2,testSource-testfeature3"}
 		fakeFeatureLabelNames := make([]string, 0, len(fakeFeatureNames))
 		for _, f := range fakeFeatureNames {

pkg/version/version.go

@@ -0,0 +1,24 @@
+/*
+Copyright 2019 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 version
+
+// Must not be const, supposed to be set using ldflags at build time
+var version = "undefined"
+
+func Get() string {
+	return version
+}