[launcher] Add version update command and show launcher version warning (#798)

## Summary

This adds a new `version update` command. It does 3 things:

* Deletes the version cache (if it exists)
* Updates the launcher 
* Updates the binary (if needed)

This can be useful for 2 cases:

* launcher is out of date
* user wishes to override the version cache.

This also adds a warning if the launcher is out of date but does not
automatically trigger the update flow.

Thoughts? 

## How was it tested?
<img width="792" alt="image"
src="https://user-images.githubusercontent.com/544948/226768704-4cf79e3c-cbe6-41a4-8b17-41762cf14df6.png">

and ran

`devbox self-update`

Author: mikeland73

internal/boxcli/root.go

@@ -13,6 +13,7 @@ import (
 	"go.jetpack.io/devbox/internal/boxcli/midcobra"
 	"go.jetpack.io/devbox/internal/cloud/openssh/sshshim"
 	"go.jetpack.io/devbox/internal/debug"
+	"go.jetpack.io/devbox/internal/vercheck"
 )
 
 var (
@@ -30,6 +31,7 @@ func RootCmd() *cobra.Command {
 		Use:   "devbox",
 		Short: "Instant, easy, predictable development environments",
 		PersistentPreRun: func(cmd *cobra.Command, args []string) {
+			vercheck.CheckLauncherVersion(cmd.ErrOrStderr())
 			if flags.quiet {
 				cmd.SetErr(io.Discard)
 			}
@@ -52,6 +54,7 @@ func RootCmd() *cobra.Command {
 	command.AddCommand(PlanCmd())
 	command.AddCommand(RemoveCmd())
 	command.AddCommand(RunCmd())
+	command.AddCommand(selfUpdateCmd())
 	command.AddCommand(ServicesCmd())
 	command.AddCommand(SetupCmd())
 	command.AddCommand(ShellCmd())

internal/boxcli/version.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"go.jetpack.io/devbox/internal/build"
+	"go.jetpack.io/devbox/internal/vercheck"
 )
 
 type versionFlags struct {
@@ -29,6 +30,20 @@ func VersionCmd() *cobra.Command {
 	command.Flags().BoolVarP(&flags.verbose, "verbose", "v", false, // value
 		"displays additional version information",
 	)
+	command.AddCommand(selfUpdateCmd())
+	return command
+}
+
+func selfUpdateCmd() *cobra.Command {
+	command := &cobra.Command{
+		Use:   "update",
+		Short: "Update devbox launcher and binary",
+		Args:  cobra.ExactArgs(0),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return vercheck.SelfUpdate(cmd.OutOrStdout(), cmd.ErrOrStderr())
+		},
+	}
+
 	return command
 }
 

internal/vercheck/vercheck.go

@@ -0,0 +1,74 @@
+package vercheck
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+	"go.jetpack.io/devbox/internal/boxcli/usererr"
+	"go.jetpack.io/devbox/internal/cloud/envir"
+	"go.jetpack.io/devbox/internal/ux"
+	"go.jetpack.io/devbox/internal/xdg"
+	"golang.org/x/mod/semver"
+)
+
+// Keep this in-sync with latest version in launch.sh. If this version is newer
+// Than the version in launch.sh, we'll print a warning.
+const expectedLauncherVersion = "v0.1.0"
+
+func CheckLauncherVersion(w io.Writer) {
+	launcherVersion := os.Getenv("LAUNCHER_VERSION")
+	if launcherVersion == "" || envir.IsDevboxCloud() {
+		return
+	}
+
+	// If launcherVersion is invalid, this will return 0 and we won't print a warning
+	if semver.Compare("v"+launcherVersion, expectedLauncherVersion) < 0 {
+		ux.Fwarning(
+			w,
+			"newer launcher version %s is available (current = v%s), please update "+
+				"using `devbox version update`\n",
+			expectedLauncherVersion,
+			os.Getenv("LAUNCHER_VERSION"),
+		)
+	}
+}
+
+// SelfUpdate updates the devbox launcher and binary. It ignores and deletes the
+// version cache
+func SelfUpdate(stdOut, stdErr io.Writer) error {
+	installScript := ""
+	if _, err := exec.LookPath("curl"); err == nil {
+		installScript = "curl -fsSL https://get.jetpack.io/devbox | bash"
+	} else if _, err := exec.LookPath("wget"); err == nil {
+		installScript = "wget -qO- https://get.jetpack.io/devbox | bash"
+	} else {
+		return usererr.New("curl or wget is required to update devbox. Please install either and try again.")
+	}
+
+	// Delete version cache. Keep this in-sync with whatever logic is in launch.sh
+	cacheDir := xdg.CacheSubpath("devbox")
+	versionCacheFile := filepath.Join(cacheDir, "latest-version")
+	_ = os.Remove(versionCacheFile)
+
+	cmd := exec.Command("sh", "-c", installScript)
+	cmd.Stdout = stdOut
+	cmd.Stderr = stdErr
+	if err := cmd.Run(); err != nil {
+		return errors.WithStack(err)
+	}
+
+	fmt.Fprint(stdErr, "Latest version: ")
+	exe, err := os.Executable()
+	if err != nil {
+		return errors.WithStack(err)
+	}
+	cmd = exec.Command(exe, "version")
+	// The output of version is incidental, so just send it all to stdErr
+	cmd.Stdout = stdErr
+	cmd.Stderr = stdErr
+	return errors.WithStack(cmd.Run())
+}