chenhg5/cc-connect · error

write unit file: %w

Error message

write unit file: %w

What it means

Install() wraps os.WriteFile failure when writing the generated .service unit to unitPath. The unit may contain secrets, so it is written 0600; a failed write means the unit could not be persisted (permissions, read-only fs, or the path is a directory).

Source

Thrown at daemon/systemd.go:70

	unitPath := m.unitPath()

	if err := os.MkdirAll(filepath.Dir(unitPath), 0755); err != nil {
		return fmt.Errorf("create systemd dir: %w", err)
	}
	if err := os.MkdirAll(filepath.Dir(cfg.LogFile), 0755); err != nil {
		return fmt.Errorf("create log dir: %w", err)
	}

	unit := m.buildUnit(cfg)
	// 0600: unit file may contain captured secret values (config.toml ${ENV}
	// placeholders and any EnvDiscoverer extension output). For system-level
	// units (/etc/systemd/system/) the file is owned by root and remains
	// readable by root only; for user-level units under
	// ~/.config/systemd/user it remains owner-only. WriteFile only applies
	// perm on create, so Chmod afterwards is required to harden reinstalls
	// of pre-existing 0644 units from earlier cc-connect versions.
	if err := os.WriteFile(unitPath, []byte(unit), 0600); err != nil {
		return fmt.Errorf("write unit file: %w", err)
	}
	if err := os.Chmod(unitPath, 0600); err != nil {
		return fmt.Errorf("chmod unit file: %w", err)
	}

	for _, cmdArgs := range [][]string{
		m.sysArgs("daemon-reload"),
		m.sysArgs("enable", systemdServiceName),
		m.sysArgs("restart", systemdServiceName),
	} {
		if out, err := runSystemctl(cmdArgs...); err != nil {
			return fmt.Errorf("systemctl %s: %s (%w)", strings.Join(cmdArgs, " "), out, err)
		}
	}

	return nil
}

View on GitHub (pinned to 4000b2338a)

Solutions

1. Run with sudo for system-level units.
2. Ensure unitPath is not a directory: `ls -ld /etc/systemd/system/cc-connect.service`.
3. Check free disk space and mount status (`df -h`, `mount`).
4. Verify no security module (SELinux) denies the write; check `ausearch -m avc`.

Example fix

// before
cmd.Exec("cc-connect install") // as non-root: write unit file: permission denied
// after
cmd.Exec("sudo cc-connect install")

unitPath := mgr.unitPath()
if fi, err := os.Stat(unitPath); err == nil && fi.IsDir() {
    return fmt.Errorf("%s is a directory", unitPath)
}
probe, err := os.CreateTemp(filepath.Dir(unitPath), ".ccprobe")
if err != nil {
    return fmt.Errorf("unit dir not writable: %w", err)
}
probe.Close(); os.Remove(probe.Name())

func canCreateFile(dir string) bool {
    f, err := os.CreateTemp(dir, ".probe")
    if err != nil { return false }
    f.Close(); os.Remove(f.Name())
    return true
}

if err := mgr.Install(cfg); err != nil {
    var pe *fs.PathError
    if errors.As(err, &pe) && errors.Is(pe.Err, fs.ErrPermission) {
        return fmt.Errorf("run with sudo: %w", err)
    }
    return err
}

When it happens

Trigger: Calling Install when the unit directory exists but is not writable (system install without root), the unit path is a directory, or the disk is full/read-only.

Common situations: Non-root user running system install; SELinux/apparmor denying writes to /etc/systemd/system; unit left in a corrupted state by a previous failed install.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• create systemd dir: %w
• remove unit: %w
• read existing Agy hooks %s: %w
• kimi: read sessions dir: %w
• create run dir: %w

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/4a8c878f31da9583. Report an issue: GitHub.