[GSoC 2019] kubectl plugin for the Postgres operator (#579)

*  Add a prototype of a kubectl plugin for the Postgres operator
   Work done by Vineeth Pothulapati <vineethpothulapati@outlook.com>
   during Google Summer of Code 2019

kubectl-pg/cmd/version.go

@@ -0,0 +1,79 @@
+/*
+Copyright © 2019 Vineeth Pothulapati <vineethpothulapati@outlook.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+package cmd
+
+import (
+	"fmt"
+	"github.com/spf13/cobra"
+	"k8s.io/client-go/kubernetes"
+	"log"
+	"strings"
+)
+
+var KubectlPgVersion string = "1.0"
+
+// versionCmd represents the version command
+var versionCmd = &cobra.Command{
+	Use:   "version",
+	Short: "version of kubectl-pg & postgres-operator",
+	Long:  `version of kubectl-pg and current running postgres-operator`,
+	Run: func(cmd *cobra.Command, args []string) {
+		namespace, err := cmd.Flags().GetString("namespace")
+		if err != nil {
+			log.Fatal(err)
+		}
+		version(namespace)
+	},
+	Example: `
+#Lists the version of kubectl pg plugin and postgres operator in current namespace
+kubectl pg version
+
+#Lists the version of kubectl pg plugin and postgres operator in provided namespace
+kubectl pg version -n namespace01
+`,
+}
+
+func version(namespace string) {
+	fmt.Printf("kubectl-pg: %s\n", KubectlPgVersion)
+
+	config := getConfig()
+	client, err := kubernetes.NewForConfig(config)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	operatorDeployment := getPostgresOperator(client)
+	if operatorDeployment.Name == "" {
+		log.Fatal("make sure zalando's postgres operator is running")
+	}
+	operatorImage := operatorDeployment.Spec.Template.Spec.Containers[0].Image
+	imageDetails := strings.Split(operatorImage, ":")
+	imageSplit := len(imageDetails)
+	imageVersion := imageDetails[imageSplit-1]
+	fmt.Printf("Postgres-Operator: %s\n", imageVersion)
+}
+
+func init() {
+	rootCmd.AddCommand(versionCmd)
+	versionCmd.Flags().StringP("namespace", "n", DefaultNamespace, "provide the namespace.")
+}