[version] part 1: update command for devbox and launcher updates (#965)

## Summary

**Motivation:**
We want to disable auto-update for devbox CLIs. This will minimize
unexpected interruptions for our users.

To do so, we are going to do the following:

1. Update `launch.sh` file in `axiom` repo to write new versions to
`{XDG_CACHE_HOME}/devbox/available-version`.
jetify-com/axiom#3150
2. Change `devbox version update` to update the launcher (if needed) and
else, update the CLI binary. (this PR).
3. Change the `vercheck.CheckVersion` that runs in `boxcli/root.go` on
every command to check if the launcher or CLI binary versions are
out-of-date, and to print a notice if so. (reviewed in #966, but merged
into this PR)

We will cherry-pick ~these two PRs~ this PR for the next release so
auto-update stops for users.

**Implementation:**
This PR enables `jetpack version update` to:

1. Update the launcher: We detect if the launcher version is outdated,
and update it, if needed. This also updates the devbox CLI binary as a
side-effect. This requires `sudo` so we only do it, if necessary.

2. Update just the devbox CLI binary: If the launcher is up-to-date,
then we update just the devbox CLI binary.

3. Remove dependency on new code like `env` package to minimize
cherry-picking merge conflicts.

TODO:
- [x] confirm that we can switch the `devbox version` operation after an
update to `StdOut`. I feel this is better so user is informed about the
new version.
cc @mikeland86 for the above question.


Will only land this after the launch.sh file is updated in
jetify-com/axiom#3150

## How was it tested?

Did some basic testing:

hardcoded `true` to ensure `selfUpdateLauncher` runs, and did `devbox
version update`:

<img width="742" alt="Screenshot 2023-05-01 at 8 57 46 PM"
src="https://user-images.githubusercontent.com/676452/235576315-03069599-a469-4f3a-90c2-cc6a58ec648a.png">


regular `devbox version update`
<img width="332" alt="Screenshot 2023-05-01 at 8 48 20 PM"
src="https://user-images.githubusercontent.com/676452/235575369-f2a70299-4a3a-4b41-80ec-ecedb730ad0b.png">

Author: savil

internal/boxcli/root.go

@@ -33,7 +33,7 @@ func RootCmd() *cobra.Command {
 		Use:   "devbox",
 		Short: "Instant, easy, predictable development environments",
 		PersistentPreRun: func(cmd *cobra.Command, args []string) {
-			vercheck.CheckLauncherVersion(cmd.ErrOrStderr())
+			vercheck.CheckVersion(cmd.ErrOrStderr())
 			if flags.quiet {
 				cmd.SetErr(io.Discard)
 			}

internal/boxcli/version.go

@@ -5,6 +5,7 @@ package boxcli
 
 import (
 	"fmt"
+	"os"
 	"runtime"
 
 	"github.com/spf13/cobra"
@@ -56,19 +57,21 @@ func versionCmdFunc(cmd *cobra.Command, _ []string, flags versionFlags) error {
 		fmt.Fprintf(w, "Commit:      %v\n", v.Commit)
 		fmt.Fprintf(w, "Commit Time: %v\n", v.CommitDate)
 		fmt.Fprintf(w, "Go Version:  %v\n", v.GoVersion)
+		fmt.Fprintf(w, "Launcher:    %v\n", v.LauncherVersion)
 	} else {
 		fmt.Fprintf(w, "%v\n", v.Version)
 	}
 	return nil
 }
 
 type versionInfo struct {
-	Version      string
-	IsPrerelease bool
-	Platform     string
-	Commit       string
-	CommitDate   string
-	GoVersion    string
+	Version         string
+	IsPrerelease    bool
+	Platform        string
+	Commit          string
+	CommitDate      string
+	GoVersion       string
+	LauncherVersion string
 }
 
 func getVersionInfo() *versionInfo {
@@ -78,6 +81,8 @@ func getVersionInfo() *versionInfo {
 		Commit:     build.Commit,
 		CommitDate: build.CommitDate,
 		GoVersion:  runtime.Version(),
+		// Change to env.LauncherVersion. Not doing so to minimize merge conflicts.
+		LauncherVersion: os.Getenv("LAUNCHER_VERSION"),
 	}
 
 	return v

internal/vercheck/vercheck.go

@@ -4,46 +4,75 @@
 package vercheck
 
 import (
+	"bytes"
 	"fmt"
 	"io"
+	"io/fs"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
 
+	"github.com/fatih/color"
 	"github.com/pkg/errors"
+	"go.jetpack.io/devbox/internal/build"
 	"golang.org/x/mod/semver"
 
 	"go.jetpack.io/devbox/internal/boxcli/usererr"
-	"go.jetpack.io/devbox/internal/envir"
-	"go.jetpack.io/devbox/internal/ux"
 	"go.jetpack.io/devbox/internal/xdg"
 )
 
 // 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"
+// than the version in launch.sh, we'll print a notice.
+const expectedLauncherVersion = "v0.2.0"
 
-func CheckLauncherVersion(w io.Writer) {
-	launcherVersion := os.Getenv(envir.LauncherVersion)
-	if launcherVersion == "" || envir.IsDevboxCloud() {
+// currentDevboxVersion is the version of the devbox CLI binary that is currently running.
+// We use this variable so we can mock it in tests.
+var currentDevboxVersion = build.Version
+
+// envDevboxLatestVersion is the latest version available of the devbox CLI binary.
+// Change to env.DevboxLatestVersion. Not doing so to minimize merge conflicts.
+var envDevboxLatestVersion = "DEVBOX_LATEST_VERSION"
+
+// CheckVersion checks the launcher and binary versions and prints a notice if
+// they are out of date.
+func CheckVersion(w io.Writer) {
+
+	// Replace with envir.IsDevboxCloud(). Not doing so to minimize merge conflicts.
+	if os.Getenv("DEVBOX_REGION") != "" {
 		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,
-			launcherVersion,
-		)
+	launcherNotice := launcherVersionNotice()
+	if launcherNotice != "" {
+		// TODO: use ux.FNotice
+		color.New(color.FgYellow).Fprintf(w, launcherNotice)
+
+		// fallthrough to alert the user about a new Devbox CLI binary being possibly available
+	}
+
+	devboxNotice := devboxVersionNotice()
+	if devboxNotice != "" {
+		// TODO: use ux.FNotice
+		color.New(color.FgYellow).Fprintf(w, devboxNotice)
 	}
 }
 
-// SelfUpdate updates the devbox launcher and binary. It ignores and deletes the
-// version cache
+// SelfUpdate updates the devbox launcher and devbox CLI binary.
+// It ignores and deletes the version cache.
+//
+// The launcher is a wrapper bash script introduced to manage the auto-update process
+// for devbox. The production devbox application is actually this launcher script
+// that acts as "devbox" and delegates commands to the devbox CLI binary.
 func SelfUpdate(stdOut, stdErr io.Writer) error {
+	if isNewLauncherAvailable() {
+		return selfUpdateLauncher(stdOut, stdErr)
+	}
+
+	return selfUpdateDevbox(stdErr)
+}
+
+func selfUpdateLauncher(stdOut, stdErr io.Writer) error {
 	installScript := ""
 	if _, err := exec.LookPath("curl"); err == nil {
 		installScript = "curl -fsSL https://get.jetpack.io/devbox | bash"
@@ -53,26 +82,187 @@ func SelfUpdate(stdOut, stdErr io.Writer) error {
 		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)
+	// Delete current version file. This will trigger an update when invoking any devbox command;
+	// in this case, inside triggerUpdate function.
+	if err := removeCurrentVersionFile(); err != nil {
+		return err
+	}
 
+	// Fetch the new launcher.
 	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()
+	// Invoke a devbox command to trigger an update of the devbox CLI binary.
+	updated, err := triggerUpdate(stdErr)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	printSuccessMessage(stdErr, "Launcher", currentLauncherVersion(), updated.launcherVersion)
+	printSuccessMessage(stdErr, "Devbox", currentDevboxVersion, updated.devboxVersion)
+
+	return nil
+}
+
+// selfUpdateDevbox will update the devbox CLI binary to the latest version.
+func selfUpdateDevbox(stdErr io.Writer) error {
+	// Delete current version file. This will trigger an update when the next devbox command is run;
+	// in this case, inside triggerUpdate function.
+	if err := removeCurrentVersionFile(); err != nil {
+		return err
+	}
+
+	updated, err := triggerUpdate(stdErr)
 	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
+
+	printSuccessMessage(stdErr, "Devbox", currentDevboxVersion, updated.devboxVersion)
+
+	return nil
+}
+
+type updatedVersions struct {
+	devboxVersion   string
+	launcherVersion string
+}
+
+// triggerUpdate runs `devbox version -v` and triggers an update since a new
+// version is available. It parses the output to get the new launcher and
+// devbox versions.
+func triggerUpdate(stdErr io.Writer) (*updatedVersions, error) {
+
+	exe, err := os.Executable()
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+	// TODO savil. Add a --json flag to devbox version and parse the output as JSON
+	cmd := exec.Command(exe, "version", "-v")
+
+	buf := new(bytes.Buffer)
+	cmd.Stdout = io.MultiWriter(stdErr, buf)
 	cmd.Stderr = stdErr
-	return errors.WithStack(cmd.Run())
+	if err := cmd.Run(); err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	// Parse the output to ascertain the new devbox and launcher versions
+	updated := &updatedVersions{}
+	for _, line := range strings.Split(buf.String(), "\n") {
+		if strings.HasPrefix(line, "Version:") {
+			updated.devboxVersion = strings.TrimSpace(strings.TrimPrefix(line, "Version:"))
+		}
+
+		if strings.HasPrefix(line, "Launcher:") {
+			updated.launcherVersion = strings.TrimSpace(strings.TrimPrefix(line, "Launcher:"))
+		}
+	}
+	return updated, nil
+}
+
+func printSuccessMessage(w io.Writer, toolName, oldVersion, newVersion string) {
+	var msg string
+	if semverCompare(oldVersion, newVersion) == 0 {
+		msg = fmt.Sprintf("already at %s version %s", toolName, newVersion)
+	} else {
+		msg = fmt.Sprintf("updated to %s version %s", toolName, newVersion)
+	}
+
+	// Prints a <green>Success:</green> message to the writer.
+	// Move to ux.Success. Not doing so to minimize merge-conflicts.
+	fmt.Fprintf(w, "%s%s\n", color.New(color.FgGreen).Sprint("Success: "), msg)
+}
+
+func launcherVersionNotice() string {
+	if !isNewLauncherAvailable() {
+		return ""
+	}
+
+	return fmt.Sprintf(
+		"New launcher available: %s -> %s. Please run `devbox version update`.\n",
+		currentLauncherVersion(),
+		expectedLauncherVersion,
+	)
+}
+
+func devboxVersionNotice() string {
+	if !isNewDevboxAvailable() {
+		return ""
+	}
+
+	return fmt.Sprintf(
+		"New devbox available: %s -> %s. Please run `devbox version update`.\n",
+		currentDevboxVersion,
+		latestVersion(),
+	)
+}
+
+// isNewLauncherAvailable returns true if a new launcher version is available.
+func isNewLauncherAvailable() bool {
+	launcherVersion := currentLauncherVersion()
+	if launcherVersion == "" {
+		return false
+	}
+	return semverCompare(launcherVersion, expectedLauncherVersion) < 0
+}
+
+// isNewDevboxAvailable returns true if a new devbox CLI binary version is available.
+func isNewDevboxAvailable() bool {
+	latest := latestVersion()
+	if latest == "" {
+		return false
+	}
+	return semverCompare(currentDevboxVersion, latest) < 0
+}
+
+// currentLauncherAvailable returns launcher's version if it is
+// available, or empty string if it is not.
+func currentLauncherVersion() string {
+	// Change to envir.LauncherVersion. Not doing so to minimize merge-conflicts.
+	launcherVersion := os.Getenv("LAUNCHER_VERSION")
+	if launcherVersion == "" {
+		return ""
+	}
+	return "v" + launcherVersion
+}
+
+func removeCurrentVersionFile() error {
+	// currentVersionFilePath is the path to the file that contains the cached
+	// version. The launcher checks this file to see if a new version is available.
+	// If the version is newer, then the launcher updates.
+	//
+	// Note: keep this in sync with launch.sh code
+	currentVersionFilePath := filepath.Join(xdg.CacheSubpath("devbox"), "current-version")
+
+	if err := os.Remove(currentVersionFilePath); err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return usererr.WithLoggedUserMessage(
+			err,
+			"Failed to delete version-cache at %s. Please manually delete it and try again.",
+			currentVersionFilePath,
+		)
+	}
+	return nil
+}
+
+func semverCompare(ver1, ver2 string) int {
+	if !strings.HasPrefix(ver1, "v") {
+		ver1 = "v" + ver1
+	}
+	if !strings.HasPrefix(ver2, "v") {
+		ver2 = "v" + ver2
+	}
+	return semver.Compare(ver1, ver2)
+}
+
+// latestVersion returns the latest version available for the binary.
+func latestVersion() string {
+	version := os.Getenv(envDevboxLatestVersion)
+	if version == "" {
+		return ""
+	}
+	return "v" + version
 }