(feat) Add auto-discovery in k8s | Adarsh

vendor/k8s.io/apimachinery/pkg/version/helpers.go

@@ -0,0 +1,88 @@
+/*
+Copyright 2018 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
+
+import (
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+type versionType int
+
+const (
+	// Bigger the version type number, higher priority it is
+	versionTypeAlpha versionType = iota
+	versionTypeBeta
+	versionTypeGA
+)
+
+var kubeVersionRegex = regexp.MustCompile("^v([\\d]+)(?:(alpha|beta)([\\d]+))?$")
+
+func parseKubeVersion(v string) (majorVersion int, vType versionType, minorVersion int, ok bool) {
+	var err error
+	submatches := kubeVersionRegex.FindStringSubmatch(v)
+	if len(submatches) != 4 {
+		return 0, 0, 0, false
+	}
+	switch submatches[2] {
+	case "alpha":
+		vType = versionTypeAlpha
+	case "beta":
+		vType = versionTypeBeta
+	case "":
+		vType = versionTypeGA
+	default:
+		return 0, 0, 0, false
+	}
+	if majorVersion, err = strconv.Atoi(submatches[1]); err != nil {
+		return 0, 0, 0, false
+	}
+	if vType != versionTypeGA {
+		if minorVersion, err = strconv.Atoi(submatches[3]); err != nil {
+			return 0, 0, 0, false
+		}
+	}
+	return majorVersion, vType, minorVersion, true
+}
+
+// CompareKubeAwareVersionStrings compares two kube-like version strings.
+// Kube-like version strings are starting with a v, followed by a major version, optional "alpha" or "beta" strings
+// followed by a minor version (e.g. v1, v2beta1). Versions will be sorted based on GA/alpha/beta first and then major
+// and minor versions. e.g. v2, v1, v1beta2, v1beta1, v1alpha1.
+func CompareKubeAwareVersionStrings(v1, v2 string) int {
+	if v1 == v2 {
+		return 0
+	}
+	v1major, v1type, v1minor, ok1 := parseKubeVersion(v1)
+	v2major, v2type, v2minor, ok2 := parseKubeVersion(v2)
+	switch {
+	case !ok1 && !ok2:
+		return strings.Compare(v2, v1)
+	case !ok1 && ok2:
+		return -1
+	case ok1 && !ok2:
+		return 1
+	}
+	if v1type != v2type {
+		return int(v1type) - int(v2type)
+	}
+	if v1major != v2major {
+		return v1major - v2major
+	}
+	return v1minor - v2minor
+}