Fix upgrade strings

main.go

@@ -1,9 +1,11 @@
 package main
 
 import (
+	"fmt"
 	"katenary/cmd"
 	"katenary/generator/writers"
 	"katenary/helm"
+	"katenary/update"
 	"strconv"
 
 	"github.com/spf13/cobra"
@@ -92,10 +94,57 @@ func main() {
 		},
 	}
 
-	rootCmd.AddCommand(versionCmd)
-	rootCmd.AddCommand(convertCmd)
-	rootCmd.AddCommand(showLabelsCmd)
+	// Update the binary to the latest version
+	updateCmd := &cobra.Command{
+		Use:   "upgrade",
+		Short: "Upgrade katenary to the latest version if available",
+		Run: func(c *cobra.Command, args []string) {
+			version, assets, err := update.CheckLatestVersion()
+			if err != nil {
+				c.Println(err)
+				return
+			}
+			c.Println("Updating to version: " + version)
+			err = update.DownloadLatestVersion(assets)
+			if err != nil {
+				c.Println(err)
+				return
+			}
+			c.Println("Update completed")
+		},
+	}
 
-	rootCmd.Execute()
+	rootCmd.AddCommand(
+		versionCmd,
+		convertCmd,
+		showLabelsCmd,
+		updateCmd,
+	)
 
+	// in parallel, check if the current katenary version is the latest
+	ch := make(chan string)
+	go func() {
+		version, _, err := update.CheckLatestVersion()
+		if err != nil {
+			ch <- ""
+			return
+		}
+		if cmd.Version != version {
+			ch <- fmt.Sprintf("\x1b[33mNew version available: " +
+				version +
+				" - to auto upgrade katenary, you can execute: katenary upgrade\x1b[0m\n")
+		}
+	}()
+
+	// Execute the command
+	finalize := make(chan error)
+	go func() {
+		finalize <- rootCmd.Execute()
+	}()
+
+	// Wait for both goroutines to finish
+	if err := <-finalize; err != nil {
+		fmt.Println(err)
+	}
+	fmt.Print(<-ch)
 }

update/main.go

@@ -0,0 +1,127 @@
+package update
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"katenary/cmd"
+	"net/http"
+	"os"
+	"runtime"
+	"time"
+)
+
+var exe, _ = os.Executable()
+
+// Asset is a github asset from release url.
+type Asset struct {
+	Name string `json:"name"`
+	URL  string `json:"browser_download_url"`
+}
+
+// CheckLatestVersion check katenary latest version from release and propose to download it
+func CheckLatestVersion() (string, []Asset, error) {
+
+	githuburl := "https://api.github.com/repos/metal3d/katenary/releases/latest"
+	// Create a HTTP client with 1s timeout
+	client := &http.Client{
+		Timeout: time.Second * 1,
+	}
+	// Create a request
+	req, err := http.NewRequest("GET", githuburl, nil)
+	if err != nil {
+		return "", nil, err
+	}
+
+	// Send the request via a client
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", nil, err
+	}
+	defer resp.Body.Close()
+
+	// Get tag_name from the json response
+	var release = struct {
+		TagName string  `json:"tag_name"`
+		Assets  []Asset `json:"assets"`
+	}{}
+	err = json.NewDecoder(resp.Body).Decode(&release)
+	if err != nil {
+		return "", nil, err
+	}
+
+	if release.TagName == "" {
+		return "", nil, errors.New("No release found")
+	}
+
+	if cmd.Version == release.TagName {
+		fmt.Println("You are using the latest version")
+		return "", nil, errors.New("You are using the latest version")
+	}
+
+	return release.TagName, release.Assets, nil
+}
+
+func DownloadLatestVersion(assets []Asset) error {
+	// Download the latest version
+	fmt.Println("Downloading the latest version...")
+
+	// ok, replace this from the current version to the latest version
+	err := os.Rename(exe, exe+".old")
+	if err != nil {
+		return err
+	}
+
+	// Download the latest version for the current OS
+	for _, asset := range assets {
+		switch runtime.GOOS {
+		case "windows":
+			if asset.Name == "katenary.exe" {
+				err = DownloadFile(asset.URL, exe)
+			}
+		case "linux":
+			switch runtime.GOARCH {
+			case "amd64":
+				if asset.Name == "katenary-linux-amd64" {
+					err = DownloadFile(asset.URL, exe)
+				}
+			case "arm64":
+				if asset.Name == "katenary-linux-arm64" {
+					err = DownloadFile(asset.URL, exe)
+				}
+			}
+		case "darwin":
+			if asset.Name == "katenary-darwin" {
+				err = DownloadFile(asset.URL, exe)
+			}
+		default:
+			fmt.Println("Unsupported OS")
+			err = errors.New("Unsupported OS")
+		}
+	}
+	if err == nil {
+		// remove the old version
+		os.Remove(exe + ".old")
+	} else {
+		// restore the old version
+		os.Rename(exe+".old", exe)
+	}
+	return err
+}
+
+func DownloadFile(url, exe string) error {
+	// Download the url binary to exe path
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	fp, err := os.OpenFile(exe, os.O_WRONLY|os.O_CREATE, 0755)
+	if err != nil {
+		return err
+	}
+	defer fp.Close()
+	_, err = io.Copy(fp, resp.Body)
+	return err
+}

update/update_test.go

@@ -0,0 +1,36 @@
+package update
+
+import (
+	"fmt"
+	"katenary/cmd"
+	"os"
+	"testing"
+)
+
+func TestDownloadLatestRelease(t *testing.T) {
+
+	// Change the cmd.Version to "v0.0.0" to test the fallback to the latest release
+	cmd.Version = "v0.0.0"
+
+	// change "exe" to /tmp/test-katenary
+	exe = "/tmp/test-katenary"
+
+	// Now call the CheckLatestVersion function
+	version, assets, err := CheckLatestVersion()
+
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+
+	fmt.Println("Version found", version)
+
+	// Touch exe binary
+	f, _ := os.OpenFile(exe, os.O_RDONLY|os.O_CREATE, 0755)
+	f.Write(nil)
+	f.Close()
+
+	err = DownloadLatestVersion(assets)
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}