auto update for npm users

Author: njyeung

homebrew-tap

@@ -30,6 +30,11 @@ func main() {
 		return
 	}
 
+	// If installed via npm and a newer release exists, swap the binary on disk
+	// and re-exec into it. Does nothing for non-npm installs or when already up
+	// to date. Must run before any child processes are spawned.
+	tui.CheckAndSelfUpdate(Version)
+
 	// Set up directories:
 	// Browser data: 	~/.local/share/reels/
 	// Cache:			~/.cache/reels/,

main.go

@@ -0,0 +1,164 @@
+package tui
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"syscall"
+	"time"
+)
+
+// CheckAndSelfUpdate. When reels was installed via npm and a newer release is
+// available, downloads the new platform binary, atomically swaps it into place
+// over the running executable, then re-execs the new binary with the same
+// argv/env. On success this function does not return, the new program takes over.
+//
+// On any failure (not npm, no update, network error, no write perms, etc.),
+// it returns silently and lets the app continue normally.
+//
+// Must be called BEFORE the TUI starts and BEFORE any child processes (Chrome)
+// are spawned, since exec replaces the current image but does not touch
+// children.
+func CheckAndSelfUpdate(currentVersion string) {
+	if currentVersion == "" || currentVersion == "dev" {
+		return
+	}
+	exePath, ok := detectNpmInstall()
+	if !ok {
+		return
+	}
+	asset, ok := releaseAssetName()
+	if !ok {
+		return
+	}
+	latest, ok := fetchLatestVersion()
+	if !ok || latest == "" || latest == currentVersion {
+		return
+	}
+
+	url := fmt.Sprintf("https://github.com/njyeung/reels/releases/download/v%s/%s", latest, asset)
+	if err := downloadAndReplace(url, exePath); err != nil {
+		fmt.Fprintf(os.Stderr, "reels: self-update failed: %v\n", err)
+		return
+	}
+
+	// Since we're on UNIX, we can re-exec the new binary with the same argv and env.
+	// On success this replaces the running process with a new process and does not return
+	if err := syscall.Exec(exePath, os.Args, os.Environ()); err != nil {
+		fmt.Fprintf(os.Stderr, "reels: failed to relaunch after update: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+// detectNpmInstall returns the resolved binary path if reels was installed via
+// npm (i.e. lives under a node_modules/@reels/<plat>/bin/reels path).
+func detectNpmInstall() (string, bool) {
+	exe, err := os.Executable()
+	if err != nil {
+		return "", false
+	}
+	resolved, err := filepath.EvalSymlinks(exe)
+	if err != nil {
+		resolved = exe
+	}
+	norm := filepath.ToSlash(resolved)
+	if !strings.Contains(norm, "/node_modules/@reels/") {
+		return "", false
+	}
+	if !strings.HasSuffix(norm, "/bin/reels") {
+		return "", false
+	}
+	return resolved, true
+}
+
+// fetchLatestVersion queries the GitHub releases API for the most recent tag
+// (with the leading "v" stripped). Used by both the pre-TUI self-update and
+// the in-TUI banner check.
+func fetchLatestVersion() (string, bool) {
+	client := &http.Client{Timeout: 3 * time.Second}
+	resp, err := client.Get("https://api.github.com/repos/njyeung/reels/releases/latest")
+	if err != nil {
+		return "", false
+	}
+	defer resp.Body.Close()
+	var release struct {
+		TagName string `json:"tag_name"`
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&release); err != nil {
+		return "", false
+	}
+	return strings.TrimPrefix(release.TagName, "v"), true
+}
+
+// releaseAssetName maps the current GOOS/GOARCH to the asset name uploaded
+// by the GitHub Actions release workflow.
+func releaseAssetName() (string, bool) {
+	switch runtime.GOOS + "/" + runtime.GOARCH {
+	case "linux/amd64":
+		return "reels-linux-amd64", true
+	case "linux/arm64":
+		return "reels-linux-arm64", true
+	case "darwin/arm64":
+		return "reels-darwin-arm64", true
+	}
+	return "", false
+}
+
+func downloadAndReplace(url, target string) error {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
+	defer cancel()
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("download failed: %s", resp.Status)
+	}
+	return writeAtomic(target, resp.Body)
+}
+
+// writeAtomic streams body into a temp file in the same directory as target,
+// then renames it onto target. On Unix this is atomic and works even if the
+// target file is currently being executed (the kernel keeps the old inode
+// alive until the process exits).
+func writeAtomic(target string, body io.Reader) error {
+	dir := filepath.Dir(target)
+	tmp, err := os.CreateTemp(dir, ".reels-update-*")
+	if err != nil {
+		return err
+	}
+	tmpPath := tmp.Name()
+	cleanup := true
+	defer func() {
+		if cleanup {
+			os.Remove(tmpPath)
+		}
+	}()
+
+	if _, err := io.Copy(tmp, body); err != nil {
+		tmp.Close()
+		return err
+	}
+	if err := tmp.Close(); err != nil {
+		return err
+	}
+	if err := os.Chmod(tmpPath, 0o755); err != nil {
+		return err
+	}
+	if err := os.Rename(tmpPath, target); err != nil {
+		return err
+	}
+	cleanup = false
+	return nil
+}

reels-bin

@@ -43,23 +43,11 @@ func (m Model) checkVersion() tea.Msg {
 	if m.version == "dev" {
 		return versionCheckMsg{}
 	}
-	client := &http.Client{Timeout: 3 * time.Second}
-	resp, err := client.Get("https://api.github.com/repos/njyeung/reels/releases/latest")
-	if err != nil {
+	latest, ok := fetchLatestVersion()
+	if !ok || latest == "" || latest == m.version {
 		return versionCheckMsg{}
 	}
-	defer resp.Body.Close()
-	var release struct {
-		TagName string `json:"tag_name"`
-	}
-	if err := json.NewDecoder(resp.Body).Decode(&release); err != nil {
-		return versionCheckMsg{}
-	}
-	latest := strings.TrimPrefix(release.TagName, "v")
-	if latest != "" && latest != m.version {
-		return versionCheckMsg{latest: latest}
-	}
-	return versionCheckMsg{}
+	return versionCheckMsg{latest: latest}
 }
 
 func renderLoadingScreen(width, height int, barText string, barStyle lipgloss.Style, scrollOffset int) string {