Add Linkerd app

Closes: #87, thank you to @phumberdroz for the initial attempt.

Tested on a new cluster.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

pkg/cmd/apps.go

@@ -45,10 +45,13 @@ func MakeApps() *cobra.Command {
 	install.AddCommand(makeInstallNginx())
 	install.AddCommand(makeInstallChart())
 	install.AddCommand(makeInstallTiller())
+	install.AddCommand(makeInstallLinkerd())
 
 	return command
 }
 
 func getApps() []string {
-	return []string{"openfaas", "nginx-ingress", "cert-manager", "openfaas-ingress", "inlets-operator", "metrics-server", "chart", "tiller"}
+	return []string{"openfaas", "nginx-ingress", "cert-manager",
+		"openfaas-ingress", "inlets-operator", "metrics-server",
+		"chart", "tiller", "linkerd"}
 }

pkg/cmd/linkerd_app.go

@@ -0,0 +1,159 @@
+package cmd
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+	"strings"
+
+	execute "github.com/alexellis/go-execute/pkg/v1"
+	"github.com/alexellis/k3sup/pkg/config"
+	"github.com/spf13/cobra"
+)
+
+func makeInstallLinkerd() *cobra.Command {
+	var linkerd = &cobra.Command{
+		Use:          "linkerd",
+		Short:        "Install linkerd",
+		Long:         `Install linkerd`,
+		Example:      `  k3sup app install linkerd`,
+		SilenceUsage: true,
+	}
+
+	linkerd.RunE = func(command *cobra.Command, args []string) error {
+		kubeConfigPath := getDefaultKubeconfig()
+
+		if command.Flags().Changed("kubeconfig") {
+			kubeConfigPath, _ = command.Flags().GetString("kubeconfig")
+		}
+		fmt.Printf("Using kubeconfig: %s\n", kubeConfigPath)
+		arch := getArchitecture()
+		fmt.Printf("Node architecture: %q\n", arch)
+
+		userPath, err := config.InitUserDir()
+		if err != nil {
+			return err
+		}
+
+		_, clientOS := getClientArch()
+
+		fmt.Printf("Client: %q\n", clientOS)
+
+		log.Printf("User dir established as: %s\n", userPath)
+
+		err = downloadLinkerd(userPath, clientOS)
+		if err != nil {
+			return err
+		}
+		fmt.Println("Running linkerd check, this may take a few moments.")
+
+		_, err = linkerdCli("check", "--pre")
+		if err != nil {
+			return err
+		}
+
+		res, err := linkerdCli("install")
+		if err != nil {
+			return err
+		}
+		file, err := ioutil.TempFile("", "linkerd")
+		w := bufio.NewWriter(file)
+		_, err = w.WriteString(res.Stdout)
+		if err != nil {
+			return err
+		}
+		w.Flush()
+
+		err = kubectl("apply", "-R", "-f", file.Name())
+		if err != nil {
+			return err
+		}
+
+		defer os.Remove(file.Name())
+
+		_, err = linkerdCli("check")
+		if err != nil {
+			return err
+		}
+
+		fmt.Println(`=======================================================================
+= Linkerd has been installed.                                        =
+=======================================================================
+
+# Get the linkerd-cli
+curl -sL https://run.linkerd.io/install | sh
+
+# Find out more at:
+# https://linkerd.io
+
+# To use the Linkerd CLI set this path:
+
+export PATH=$PATH:` + path.Join(userPath, "bin/") + `
+linkerd --help
+
+` + thanksForUsing)
+		return nil
+	}
+
+	return linkerd
+}
+
+func getLinkerdURL(os, version string) string {
+	osSuffix := strings.ToLower(os)
+	return fmt.Sprintf("https://github.com/linkerd/linkerd2/releases/download/%s/linkerd2-cli-%s-%s", version, version, osSuffix)
+}
+
+func downloadLinkerd(userPath, clientOS string) error {
+	filePath := path.Join(path.Join(userPath, "bin"), "linkerd")
+	if _, statErr := os.Stat(filePath); statErr != nil {
+		linkerdURL := getLinkerdURL(clientOS, "stable-2.6.0")
+		fmt.Println(linkerdURL)
+		parsedURL, _ := url.Parse(linkerdURL)
+
+		res, err := http.DefaultClient.Get(parsedURL.String())
+		if err != nil {
+			return err
+		}
+
+		defer res.Body.Close()
+		out, err := os.Create(filePath)
+		if err != nil {
+			return err
+		}
+		defer out.Close()
+
+		// Write the body to file
+		_, err = io.Copy(out, res.Body)
+
+		err = os.Chmod(filePath, 0755)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func linkerdCli(parts ...string) (execute.ExecResult, error) {
+	task := execute.ExecTask{
+		Command: fmt.Sprintf("%s", localBinary("linkerd")),
+		Args:    parts,
+		Env:     os.Environ(),
+	}
+	res, err := task.Execute()
+
+	if err != nil {
+		return res, err
+	}
+
+	if res.ExitCode != 0 {
+		return res, fmt.Errorf("exit code %d, stderr: %s", res.ExitCode, res.Stderr)
+	}
+
+	return res, nil
+}