From 0264f8c506425fc881efc97fda7854f83f458c4a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=80lex=20P=C3=A9rez?= <alexperezpujol@disroot.org>
Date: Sat, 27 Jun 2020 14:28:25 +0200
Subject: [PATCH] Optimize version detection

---
 internal/helpers/kube_client.go | 86 +++++++++++++++++++++++----------
 internal/wrapper/main.go        |  1 -
 2 files changed, 61 insertions(+), 26 deletions(-)

diff --git a/internal/helpers/kube_client.go b/internal/helpers/kube_client.go
index 12ff982..ce7faf6 100644
--- a/internal/helpers/kube_client.go
+++ b/internal/helpers/kube_client.go
@@ -7,47 +7,65 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
+
+	"os/exec"
+	"runtime"
 
 	"github.com/mitchellh/go-homedir"
 	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
 )
 
 func KubeGetVersion() (string, error) {
-	var kubeconfig *string
+	var kubeconfig string
+	var cli *string
 	var err error
 	var home string
 	var version string
+	var config *rest.Config
 
-	home, _ = homedir.Dir()
-
-	kubeconfigVar := os.Getenv("KUBECONFIG")
+	cli = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
+	flag.Parse()
 
-	if kubeconfigVar != "" { // nolint: gocritic
-		kubeconfig = flag.String("kubeconfig", kubeconfigVar, "absolute path to the kubeconfig file")
-	} else if FileExists(filepath.Join(home, ".kube", "config")) {
-		kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "config"), "absolute path to the kubeconfig file")
+	// Try first --kubeconfig parameter
+	if *cli != "" {
+		kubeconfig = *cli
 	} else {
-		kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
+		home, _ = homedir.Dir()
+
+		kubeconfigVar := os.Getenv("KUBECONFIG")
+
+		// Try first KUBECONFIG env var
+		// If not set, try default kubeconfig path
+		// If not find, let it empty
+		if kubeconfigVar != "" { // nolint: gocritic
+			kubeconfig = kubeconfigVar
+		} else if FileExists(filepath.Join(home, ".kube", "config")) {
+			kubeconfig = filepath.Join(home, ".kube", "config")
+		}
 	}
 
-	flag.Parse()
-
-	config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
-	if err != nil {
-		version = getLatestVersion()
+	// If no kubeconfig
+	if kubeconfig == "" {
+		version = getDefaultVersion()
 		return version, nil
 	}
 
+	config, _ = clientcmd.BuildConfigFromFlags("", kubeconfig)
+	config.Timeout = 1 * time.Second
+
 	client, err := kubernetes.NewForConfig(config)
+
 	if err != nil {
-		version = getLatestVersion()
+		version = getDefaultVersion()
 		return version, nil
 	}
 
 	v, err := client.DiscoveryClient.ServerVersion()
 	if err != nil {
-		version = getLatestVersion()
+		version = getDefaultVersion()
 		return version, nil
 	}
 
@@ -56,19 +74,37 @@ func KubeGetVersion() (string, error) {
 	return version, nil
 }
 
-func getLatestVersion() string {
-	resp, err := http.Get("https://storage.googleapis.com/kubernetes-release/release/stable.txt")
-	CheckGenericError(err)
+func getDefaultVersion() string {
+	var fileExt string
+	var version string
+
+	if runtime.GOOS == "windows" {
+		fileExt = ".exe"
+	}
 
-	defer resp.Body.Close()
+	// See if there's any kubectl version installed
+	args := []string{"list", "local"}
+	cmd := exec.Command("kbenv"+fileExt, args...) // nolint: gosec
+	output, _ := cmd.Output()
+	out := string(output)
 
-	body, err := ioutil.ReadAll(resp.Body)
-	CheckGenericError(err)
+	// If there's no kubectl, get latest
+	// If there's at least one, use that
+	if out == "" {
+		resp, err := http.Get("https://storage.googleapis.com/kubernetes-release/release/stable.txt")
+		CheckGenericError(err)
 
-	bodyText := string(body)
-	version := bodyText[1:]
+		defer resp.Body.Close()
 
-	version = strings.Trim(version, "\n")
+		body, err := ioutil.ReadAll(resp.Body)
+		CheckGenericError(err)
+
+		bodyText := string(body)
+		version = strings.Trim(bodyText[1:], "\n")
+	} else {
+		lines := strings.Split(out, "\n")
+		version = lines[0]
+	}
 
 	return version
 }
diff --git a/internal/wrapper/main.go b/internal/wrapper/main.go
index 676f55c..e9ef4a0 100644
--- a/internal/wrapper/main.go
+++ b/internal/wrapper/main.go
@@ -71,7 +71,6 @@ func Wrapper(binName string) { // nolint: funlen
 		if !helpers.FileExists(bin) {
 			args := []string{"install", version}
 			cmd := exec.Command("kbenv"+fileExt, args...) // nolint: gosec
-			cmd.Stdout = os.Stdout
 			cmd.Stderr = os.Stderr
 			err = cmd.Run()