defang upgrade command (#439)

* defang update command

* print update instructions

we decided we didn't feel comfortable with proactively trying to run
other processes to update.

we may revisit this in the future, but for now this is a practical
compromise.

* improve detection of homebrew installation

* TIL: Println doesn't unescape newlines

* print with term

* dont print more than once

* s/update/upgrade/g

* mention defang upgrade in the upgrade hint

---------

Co-authored-by: Jordan Stephens <[email protected]>

Author: lionello

src/cmd/cli/command/commands.go

@@ -154,6 +154,9 @@ func SetupCommands(version string) {
 	tosCmd.Flags().Bool("agree-tos", false, "agree to the Defang terms of service")
 	RootCmd.AddCommand(tosCmd)
 
+	// Upgrade command
+	RootCmd.AddCommand(upgradeCmd)
+
 	// Token command
 	tokenCmd.Flags().Duration("expires", 24*time.Hour, "validity duration of the token")
 	tokenCmd.Flags().String("scope", "", fmt.Sprintf("scope of the token; one of %v (required)", scope.All())) // TODO: make it an Option
@@ -317,8 +320,8 @@ var RootCmd = &cobra.Command{
 			version := cmd.Root().Version // HACK to avoid circular dependency with RootCmd
 			term.Debug("Fabric:", v.Fabric, "CLI:", version, "CLI-Min:", v.CliMin)
 			if hasTty && isNewer(version, v.CliMin) {
-				term.Warn("Your CLI version is outdated. Please update to the latest version.")
-				os.Setenv("DEFANG_HIDE_UPDATE", "1") // hide the update hint at the end
+				term.Warn("Your CLI version is outdated. Please upgrade to the latest version by running:\n\ndefang upgrade")
+				os.Setenv("DEFANG_HIDE_UPDATE", "1") // hide the upgrade hint at the end
 			}
 		}
 
@@ -959,6 +962,16 @@ var tosCmd = &cobra.Command{
 	},
 }
 
+var upgradeCmd = &cobra.Command{
+	Use:     "upgrade",
+	Args:    cobra.NoArgs,
+	Aliases: []string{"update"},
+	Short:   "Upgrade the Defang CLI to the latest version",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return cli.Upgrade(cmd.Context())
+	},
+}
+
 func configureLoader(cmd *cobra.Command) compose.Loader {
 	f := cmd.Flags()
 	o := compose.LoaderOptions{}

src/pkg/cli/upgrade.go

@@ -0,0 +1,75 @@
+package cli
+
+import (
+	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/DefangLabs/defang/src/pkg/term"
+)
+
+func Upgrade(ctx context.Context) error {
+	// Find path to the current executable to determine how to upgrade
+	ex, err := os.Executable()
+	if err != nil {
+		return err
+	}
+	term.Debugf(" - Executable: %s\n", ex)
+
+	ex, err = filepath.EvalSymlinks(ex)
+	if err != nil {
+		return err
+	}
+	term.Debugf(" - Evaluated: %s\n", ex)
+
+	if strings.HasPrefix(ex, homebrewPrefix(ctx)) {
+		printInstructions("brew upgrade defang")
+		return nil
+	}
+
+	if strings.HasPrefix(ex, "/nix/store/") {
+		// Detect whether the user has used Flakes or nix-env
+		if strings.Contains("-defang-cli-", ex) {
+			printInstructions("nix-env -if https://github.com/DefangLabs/defang/archive/main.tar.gz")
+		} else {
+			printInstructions("nix profile install github:DefangLabs/defang#defang-bin --refresh")
+		}
+		return nil
+	}
+
+	// Check if we're running in PowerShell
+	if _, exists := os.LookupEnv("PSModulePath"); exists {
+		printInstructions(`pwsh -c "iwr https://s.defang.io/defang_win_amd64.zip -OutFile defang.zip"`)
+
+		return nil
+	}
+
+	// Default to the shell script
+	printInstructions(`. <(curl -Ls https://s.defang.io/install)`)
+
+	return nil
+}
+
+func homebrewPrefix(ctx context.Context) string {
+	output, err := exec.CommandContext(ctx, "brew", "config").Output()
+	if err != nil {
+		return ""
+	}
+	homebrewPrefix := ""
+	// filter out the line which includes HOMEBREW_PREFIX
+	for _, line := range strings.Split(string(output), "\n") {
+		config_key := "HOMEBREW_PREFIX: "
+		if strings.HasPrefix(line, config_key) {
+			// remove the prefix from the line
+			homebrewPrefix = strings.TrimPrefix(line, config_key)
+			break
+		}
+	}
+	return homebrewPrefix
+}
+
+func printInstructions(cmd string) {
+	term.Info("To upgrade defang, run the following command:\n\n", cmd)
+}