add semver parsing of gitversion to pkg/version

pkg/version/semver.go

+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+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
+
+import (
+	"strings"
+	"unicode"
+
+	"github.com/blang/semver"
+	"github.com/golang/glog"
+)
+
+func Parse(gitversion string) (semver.Version, error) {
+	// optionally trim leading spaces then one v
+	var seen bool
+	gitversion = strings.TrimLeftFunc(gitversion, func(ch rune) bool {
+		if seen {
+			return false
+		}
+		if ch == 'v' {
+			seen = true
+			return true
+		}
+		return unicode.IsSpace(ch)
+	})
+
+	return semver.Make(gitversion)
+}
+
+func MustParse(gitversion string) semver.Version {
+	v, err := Parse(gitversion)
+	if err != nil {
+		glog.Fatalf("failed to parse semver from giversion %q: %v", gitversion, err)
+	}
+	return v
+}

pkg/version/semver_test.go

+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+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
+
+import "testing"
+
+func TestParseVersion(t *testing.T) {
+	cases := []struct {
+		version   string
+		expectErr bool
+	}{
+		{version: "v1.0.1-alpha"},
+		{version: "v0.19.3"},
+		{version: "0.19.3"},
+		{version: "v1.2.0-alpha.3.1264+0655e65b435106-dirty"},
+		{version: "1.2.0-alpha.3.1264+0655e65b435106-dirty"},
+		{version: "1.2.0-alpha.3.1264+0655e65b435106-dirty"},
+		{version: "1.0.0"},
+		{version: "\t v1.0.0"},
+		{version: "vv1.0.0", expectErr: true},
+		{version: "blah1.0.0", expectErr: true},
+	}
+
+	for i, c := range cases {
+		_, err := Parse(c.version)
+		if err != nil && !c.expectErr {
+			t.Errorf("[%v]unexpected error: %v", i, err)
+		}
+		if err == nil && c.expectErr {
+			t.Errorf("[%v]expected error for %s", i, c.version)
+		}
+	}
+}