fix(gateway): self-request service restarts when invoked in-process

hermes_cli/gateway.py

@@ -100,6 +100,59 @@ def _get_service_pids() -> set:
     return pids
 
 
+def _get_parent_pid(pid: int) -> int | None:
+    """Return the parent PID for ``pid``, or ``None`` when unavailable."""
+    if pid <= 1:
+        return None
+    try:
+        result = subprocess.run(
+            ["ps", "-o", "ppid=", "-p", str(pid)],
+            capture_output=True,
+            text=True,
+            timeout=5,
+        )
+    except (FileNotFoundError, subprocess.TimeoutExpired):
+        return None
+    if result.returncode != 0:
+        return None
+    raw = result.stdout.strip()
+    if not raw:
+        return None
+    try:
+        parent_pid = int(raw.splitlines()[-1].strip())
+    except ValueError:
+        return None
+    return parent_pid if parent_pid > 0 else None
+
+
+def _is_pid_ancestor_of_current_process(target_pid: int) -> bool:
+    """Return True when ``target_pid`` is this process or one of its ancestors."""
+    if target_pid <= 0:
+        return False
+
+    pid = os.getpid()
+    seen: set[int] = set()
+    while pid and pid not in seen:
+        if pid == target_pid:
+            return True
+        seen.add(pid)
+        pid = _get_parent_pid(pid) or 0
+    return False
+
+
+def _request_gateway_self_restart(pid: int) -> bool:
+    """Ask a running gateway ancestor to restart itself asynchronously."""
+    if not hasattr(signal, "SIGUSR1"):
+        return False
+    if not _is_pid_ancestor_of_current_process(pid):
+        return False
+    try:
+        os.kill(pid, signal.SIGUSR1)
+    except (ProcessLookupError, PermissionError, OSError):
+        return False
+    return True
+
+
 def find_gateway_pids(exclude_pids: set | None = None) -> list:
     """Find PIDs of running gateway processes.
 
@@ -971,6 +1024,12 @@ def systemd_restart(system: bool = False):
     if system:
         _require_root_for_system_service("restart")
     refresh_systemd_unit_if_needed(system=system)
+    from gateway.status import get_running_pid
+
+    pid = get_running_pid()
+    if pid is not None and _request_gateway_self_restart(pid):
+        print(f"✓ {_service_scope_label(system).capitalize()} service restart requested")
+        return
     subprocess.run(_systemctl_cmd(system) + ["reload-or-restart", get_service_name()], check=True, timeout=90)
     print(f"✓ {_service_scope_label(system).capitalize()} service restarted")
 
@@ -1309,6 +1368,9 @@ def launchd_restart():
 
     try:
         pid = get_running_pid()
+        if pid is not None and _request_gateway_self_restart(pid):
+            print("✓ Service restart requested")
+            return
         if pid is not None:
             try:
                 terminate_pid(pid, force=False)

tests/hermes_cli/test_gateway_service.py

@@ -243,6 +243,7 @@ class TestLaunchdServiceRecovery:
         target = f"{gateway_cli._launchd_domain()}/{gateway_cli.get_launchd_label()}"
 
         monkeypatch.setattr(gateway_cli, "_get_restart_drain_timeout", lambda: 12.0)
+        monkeypatch.setattr(gateway_cli, "_request_gateway_self_restart", lambda pid: False)
         monkeypatch.setattr(gateway_cli, "_wait_for_gateway_exit", lambda timeout, force_after=None: True)
         monkeypatch.setattr(gateway_cli, "terminate_pid", lambda pid, force=False: calls.append(("term", pid, force)))
         monkeypatch.setattr(
@@ -263,6 +264,29 @@ class TestLaunchdServiceRecovery:
             ["launchctl", "kickstart", "-k", target],
         ]
 
+    def test_launchd_restart_self_requests_graceful_restart_without_kickstart(self, monkeypatch, capsys):
+        calls = []
+
+        monkeypatch.setattr(
+            "gateway.status.get_running_pid",
+            lambda: 321,
+        )
+        monkeypatch.setattr(
+            gateway_cli,
+            "_request_gateway_self_restart",
+            lambda pid: calls.append(("self", pid)) or True,
+        )
+        monkeypatch.setattr(
+            gateway_cli.subprocess,
+            "run",
+            lambda *args, **kwargs: (_ for _ in ()).throw(AssertionError("launchctl should not run")),
+        )
+
+        gateway_cli.launchd_restart()
+
+        assert calls == [("self", 321)]
+        assert "restart requested" in capsys.readouterr().out.lower()
+
     def test_launchd_stop_uses_bootout_not_kill(self, monkeypatch):
         """launchd_stop must bootout the service so KeepAlive doesn't respawn it."""
         label = gateway_cli.get_launchd_label()
@@ -366,6 +390,31 @@ class TestGatewayServiceDetection:
 
 
 class TestGatewaySystemServiceRouting:
+    def test_systemd_restart_self_requests_graceful_restart_without_reload_or_restart(self, monkeypatch, capsys):
+        calls = []
+
+        monkeypatch.setattr(gateway_cli, "_select_systemd_scope", lambda system=False: False)
+        monkeypatch.setattr(gateway_cli, "refresh_systemd_unit_if_needed", lambda system=False: calls.append(("refresh", system)))
+        monkeypatch.setattr(
+            "gateway.status.get_running_pid",
+            lambda: 654,
+        )
+        monkeypatch.setattr(
+            gateway_cli,
+            "_request_gateway_self_restart",
+            lambda pid: calls.append(("self", pid)) or True,
+        )
+        monkeypatch.setattr(
+            gateway_cli.subprocess,
+            "run",
+            lambda *args, **kwargs: (_ for _ in ()).throw(AssertionError("systemctl should not run")),
+        )
+
+        gateway_cli.systemd_restart()
+
+        assert calls == [("refresh", False), ("self", 654)]
+        assert "restart requested" in capsys.readouterr().out.lower()
+
     def test_gateway_install_passes_system_flags(self, monkeypatch):
         monkeypatch.setattr(gateway_cli, "supports_systemd_services", lambda: True)
         monkeypatch.setattr(gateway_cli, "is_termux", lambda: False)