feat: [WIP] implement scp by bgo

app.go

@@ -340,12 +340,16 @@ func (a *App) runSaveRemotePipeline(pngBytes []byte) error {
 		"auth_method", cfg.SSH.AuthMethod, "png_size", len(pngBytes))
 
 	// Select the uploader by auth method: Kerberos delegates to the system
-	// ssh/scp binaries (reusing the kinit credential cache), while builtin
-	// uses the in-process Go SSH client.
+	// ssh/scp binaries (reusing the kinit credential cache), bgo delegates to
+	// the internal `bgo scp` client (under a PTY), while builtin uses the
+	// in-process Go SSH client.
 	var uploader application.SSHUploader
-	if cfg.SSH.IsKerberos() {
+	switch {
+	case cfg.SSH.IsKerberos():
 		uploader = sshpkg.NewKerberosUploader(cfg.SSH)
-	} else {
+	case cfg.SSH.IsBgo():
+		uploader = sshpkg.NewBgoUploader(cfg.SSH)
+	default:
 		uploader = sshpkg.NewUploader(cfg.SSH)
 	}
 
@@ -467,6 +471,15 @@ func (a *App) TestSSHConnection(cfg domain.SSHConfig) error {
 		}
 		return nil
 	}
+	// bgo manages its own auth; we can only confirm the binary is installed
+	// and resolvable (a real transfer would need a live remote + PTY).
+	if cfg.IsBgo() {
+		if err := sshpkg.TestBgoConnection(a.ctx, cfg); err != nil {
+			slog.Error("RPC TestSSHConnection (bgo) failed", "err", err)
+			return err
+		}
+		return nil
+	}
 	if err := sshpkg.TestConnection(a.ctx, cfg); err != nil {
 		slog.Error("RPC TestSSHConnection failed", "err", err)
 		return err

frontend/src/views/SettingsView.vue

@@ -289,6 +289,7 @@ onMounted(load)
               <option value="password">Password</option>
               <option value="key">SSH-Key</option>
               <option value="kerberos">Kerberos</option>
+              <option value="bgo">bgo</option>
             </select>
           </label>
           <label class="field">
@@ -350,6 +351,18 @@ onMounted(load)
         keys. Make sure password-less login already works (e.g. via
         <code>ssh-copy-id</code>).
       </p>
+      <p v-else-if="config.ssh.authMethod === 'bgo'" class="hint">
+        bgo mode delegates uploads to the internal <code>bgo scp</code> client,
+        which handles authentication itself. Install bgo and add it to your
+        <code>PATH</code> first — see the
+        <a
+          href="https://bytedance.larkoffice.com/wiki/HpUCw7qRDiW66YkzKdwcXYrTnLf"
+          target="_blank"
+          rel="noopener"
+        >setup guide</a>.
+        Note: bgo cannot create remote directories, so screenshots are saved
+        flat into the remote home directory (the Remote path setting is ignored).
+      </p>
       <p
         v-else-if="config.ssh.authMethod === 'password' && !config.ssh.password"
         class="hint warn"

internal/application/capture_ssh.go

@@ -69,6 +69,12 @@ func (s *CaptureAndSSHService) ExecuteWithBytes(ctx context.Context, pngBytes []
 		return fmt.Errorf("empty screenshot")
 	}
 	relPath := buildRemoteRelPath(s.Cfg.PathPrefix)
+	// bgo cannot create remote directories, so it uploads flat into the
+	// remote $HOME with a timestamped filename rather than a date-grouped
+	// subdirectory tree (see BgoUploader for the rationale).
+	if s.Cfg.IsBgo() {
+		relPath = buildRemoteFlatName()
+	}
 	sshSvcLog().Info("save-remote pipeline start",
 		"host", s.Cfg.Host, "user", s.Cfg.User, "port", s.Cfg.Port,
 		"size", len(pngBytes), "remote_path", relPath,
@@ -128,6 +134,17 @@ func buildRemoteRelPath(prefix string) string {
 	)
 }
 
+// buildRemoteFlatName produces a flat, timestamped filename (no directory
+// components) for destinations that cannot create remote directories, such
+// as the bgo client. The file lands directly in the remote $HOME.
+func buildRemoteFlatName() string {
+	now := time.Now()
+	return fmt.Sprintf("%s-%s.png",
+		now.Format("20060102-150405"),
+		randomSuffix(6),
+	)
+}
+
 func (s *CaptureAndSSHService) notifyFailure(reason string) {
 	if s.Notifier != nil {
 		s.Notifier.NotifyFailure(reason)

internal/domain/config.go

@@ -42,6 +42,11 @@ type S3Config struct {
 //     `kinit` is reused. Native GSSAPI is required here
 //     because macOS stores tickets in an API: ccache
 //     that pure-Go SSH libraries cannot read.
+//     "bgo"          → delegate to the internal `bgo scp` client which
+//     handles its own auth/credential management. bgo
+//     must run under a PTY and cannot create remote
+//     directories, so this mode uploads to the user's
+//     remote $HOME with a flat, timestamped filename.
 //     "" / "builtin" → legacy combined behaviour (password → agent → key
 //     files) kept only for backward compatibility with
 //     configs written before the method was split.
@@ -85,6 +90,10 @@ const (
 	// SSHAuthKerberos delegates to the system ssh binary so an existing
 	// Kerberos credential cache (populated by `kinit`) is reused via GSSAPI.
 	SSHAuthKerberos = "kerberos"
+	// SSHAuthBgo delegates to the internal `bgo scp` client, which manages
+	// its own authentication. bgo requires a PTY and cannot create remote
+	// directories, so uploads land flat in the remote $HOME.
+	SSHAuthBgo = "bgo"
 )
 
 // IsKerberos reports whether this config requests Kerberos/GSSAPI auth.
@@ -92,6 +101,11 @@ func (c SSHConfig) IsKerberos() bool {
 	return c.AuthMethod == SSHAuthKerberos
 }
 
+// IsBgo reports whether this config requests the internal bgo client.
+func (c SSHConfig) IsBgo() bool {
+	return c.AuthMethod == SSHAuthBgo
+}
+
 // AppConfig is the top-level on-disk configuration document.
 //
 // We keep S3 / SSH nested so that adding more providers later (e.g. AliyunOSS,

internal/infrastructure/ssh/bgo_uploader.go

@@ -0,0 +1,200 @@
+// bgo_uploader.go — an SSHUploader implementation that delegates to the
+// internal `bgo scp` client. bgo is ByteDance's internal credential/auth
+// management tool; it wraps ssh/scp and handles login transparently once the
+// user has configured it (see the Lark guide linked in the Settings UI).
+//
+// 设计理由 (为什么不能直接 exec bgo, 也不能复用 KerberosUploader):
+//   - bgo 强制要求在 PTY (伪终端) 下运行: 它会对 stdin/stdout 做终端 ioctl
+//     (resize pty). 没有 PTY 时直接 panic ("operation not supported by
+//     device"). 因此必须用系统 /usr/bin/script 为其分配一个伪终端:
+//         script -q /dev/null <bgo> scp <src> <user@host:dst>
+//     这样既不引入额外的 PTY 依赖, 又满足 bgo 的运行约束.
+//   - bgo scp 不会自动创建远程目录, 且 bgo ssh 无法执行远程命令 (会 panic),
+//     所以无法像 Kerberos 那样先 `mkdir -p`. 故 bgo 模式只能把文件平铺上传
+//     到远端用户的 $HOME 根目录 (文件名内嵌时间戳保证唯一), 上层 service
+//     负责生成扁平文件名.
+//   - bgo 自带鉴权, 不需要也不应传 GSSAPI / 密码 / 公钥相关的 ssh 选项.
+package ssh
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/mmmy/snapgo/internal/domain"
+)
+
+// systemScriptPath is the absolute path to the macOS BSD `script` utility,
+// which we use purely to allocate a PTY for bgo. Absolute path avoids PATH
+// hijacking and the minimal PATH GUI apps inherit on macOS.
+const systemScriptPath = "/usr/bin/script"
+
+// bgoSearchPaths lists the locations we probe for the bgo binary when it is
+// not already resolvable via $PATH. GUI apps on macOS launch with a minimal
+// PATH that usually omits ~/.local/bin and Homebrew dirs, so we look there
+// explicitly rather than failing with a confusing "command not found".
+func bgoSearchPaths() []string {
+	home, _ := os.UserHomeDir()
+	return []string{
+		filepath.Join(home, ".local", "bin", "bgo"),
+		"/usr/local/bin/bgo",
+		"/opt/homebrew/bin/bgo",
+		"/opt/bin/bgo",
+	}
+}
+
+// BgoUploader satisfies application.SSHUploader by shelling out to `bgo scp`
+// under a PTY allocated via the system `script` utility.
+type BgoUploader struct {
+	cfg domain.SSHConfig
+}
+
+// NewBgoUploader returns an uploader that delegates to the bgo client.
+func NewBgoUploader(cfg domain.SSHConfig) *BgoUploader {
+	return &BgoUploader{cfg: cfg}
+}
+
+// resolveBgoBinary locates the bgo executable, first via $PATH and then via
+// the well-known install locations. Returns a clear error pointing the user
+// to the setup guide when bgo cannot be found.
+func resolveBgoBinary() (string, error) {
+	if p, err := exec.LookPath("bgo"); err == nil {
+		return p, nil
+	}
+	for _, candidate := range bgoSearchPaths() {
+		if info, err := os.Stat(candidate); err == nil && !info.IsDir() {
+			return candidate, nil
+		}
+	}
+	return "", fmt.Errorf("bgo executable not found — install bgo and add it to PATH (see the setup guide)")
+}
+
+// Upload writes data to a flat remote filename in the user's remote $HOME by
+// staging it locally and invoking `bgo scp` once under a PTY.
+//
+// remoteRelPath is expected to be a flat filename (no directory components),
+// because bgo cannot create remote directories. Any directory components are
+// collapsed to the base name defensively.
+func (u *BgoUploader) Upload(ctx context.Context, remoteRelPath string, data []byte, mode os.FileMode) error {
+	start := time.Now()
+	// Collapse to a flat filename: bgo scp cannot create remote directories.
+	name := path.Base(normaliseRemotePath(remoteRelPath))
+	if name == "" || name == "." || name == "/" {
+		return fmt.Errorf("ssh(bgo): remote filename is empty")
+	}
+
+	bgoBin, err := resolveBgoBinary()
+	if err != nil {
+		sshLog().Error("bgo uploader: binary not found", "err", err)
+		return err
+	}
+
+	sshLog().Info("bgo uploader start",
+		"host", u.cfg.Host, "user", u.cfg.User, "port", u.cfg.Port,
+		"remote_file", name, "size", len(data), "bgo", bgoBin)
+
+	// 1. Stage the payload to a local temp file for scp to read.
+	tmp, err := os.CreateTemp("", "snapgo-bgo-*.png")
+	if err != nil {
+		return fmt.Errorf("ssh(bgo): create temp: %w", err)
+	}
+	tmpPath := tmp.Name()
+	defer os.Remove(tmpPath)
+	if _, err := tmp.Write(data); err != nil {
+		_ = tmp.Close()
+		return fmt.Errorf("ssh(bgo): write temp: %w", err)
+	}
+	if err := tmp.Close(); err != nil {
+		return fmt.Errorf("ssh(bgo): close temp: %w", err)
+	}
+	if err := os.Chmod(tmpPath, mode.Perm()); err != nil {
+		sshLog().Debug("bgo uploader chmod temp failed", "err", err)
+	}
+
+	// 2. bgo scp <tmp> <user@host:name> under a PTY (via `script`).
+	remoteTarget := fmt.Sprintf("%s@%s:%s", u.cfg.User, bracketHost(u.cfg.Host), name)
+	bgoArgs := u.bgoScpArgs(bgoBin, tmpPath, remoteTarget)
+	if err := u.runUnderPTY(ctx, bgoArgs); err != nil {
+		sshLog().Error("bgo uploader scp failed",
+			"remote_file", name, "elapsed", time.Since(start), "err", err)
+		return err
+	}
+	sshLog().Info("bgo uploader done",
+		"remote_file", name, "size", len(data), "total_elapsed", time.Since(start))
+	return nil
+}
+
+// bgoScpArgs builds the argument vector "bgo scp [-P port] <src> <dst>".
+// bgo manages its own auth, so we pass no ssh -o options here.
+func (u *BgoUploader) bgoScpArgs(bgoBin, src, dst string) []string {
+	args := []string{bgoBin, "scp"}
+	if u.cfg.Port > 0 && u.cfg.Port != 22 {
+		args = append(args, "-P", strconv.Itoa(u.cfg.Port))
+	}
+	args = append(args, src, dst)
+	return args
+}
+
+// runUnderPTY runs the given command vector under a PTY allocated by the
+// system `script` utility, capturing combined output for diagnostics.
+//
+// macOS BSD script signature: `script -q <typescript-file> command [args...]`.
+// We discard the typescript by writing to /dev/null.
+func (u *BgoUploader) runUnderPTY(ctx context.Context, cmdVec []string) error {
+	args := append([]string{"-q", "/dev/null"}, cmdVec...)
+	cmd := exec.CommandContext(ctx, systemScriptPath, args...)
+	var combined bytes.Buffer
+	cmd.Stdout = &combined
+	cmd.Stderr = &combined
+	sshLog().Debug("bgo exec", "args", strings.Join(args, " "))
+	if err := cmd.Run(); err != nil {
+		msg := strings.TrimSpace(combined.String())
+		if msg == "" {
+			msg = err.Error()
+		}
+		return fmt.Errorf("bgo scp failed: %s", msg)
+	}
+	return nil
+}
+
+// bracketHost wraps a bare IPv6 literal in [] so the "user@host:path" target
+// parses correctly (e.g. fdbd:dc03:8:379::130 → [fdbd:dc03:8:379::130]).
+// IPv4 addresses and hostnames are returned unchanged. Already-bracketed
+// inputs are left as-is.
+func bracketHost(host string) string {
+	host = strings.TrimSpace(host)
+	if host == "" {
+		return host
+	}
+	if strings.HasPrefix(host, "[") {
+		return host
+	}
+	// An IPv6 literal contains multiple ':' separators; a hostname:port style
+	// is not expected here because the port lives in cfg.Port.
+	if strings.Count(host, ":") >= 2 {
+		return "[" + host + "]"
+	}
+	return host
+}
+
+// TestBgoConnection verifies that the bgo binary is resolvable. A real
+// transfer test is intentionally avoided: bgo requires a PTY and a live
+// remote, and bgo ssh cannot run a harmless remote probe command (it panics).
+// Confirming bgo is installed and on PATH is the most useful signal we can
+// give without performing an actual upload.
+func TestBgoConnection(ctx context.Context, cfg domain.SSHConfig) error {
+	sshLog().Info("bgo test connection start", "host", cfg.Host, "user", cfg.User)
+	bin, err := resolveBgoBinary()
+	if err != nil {
+		return err
+	}
+	sshLog().Info("bgo test connection ok", "bgo", bin)
+	return nil
+}