The in-chat /restart command was leaving the gateway dead on systemd
deployments using Restart=on-failure (the default for many
operator-managed and tutorial-style unit files). The gateway drained,
exited cleanly (code 0), and was never revived — the only recovery was
a host reboot.
Root cause was a multi-layer assumption mismatch:
1. gateway/run.py:_stop_impl assumed all systemd units use
Restart=always, so the Linux/systemd branch returned exit code 0
and relied on a `systemd-run` transient helper to restart the unit
immediately. Units with Restart=on-failure never see a clean exit
as a trigger, so nothing revived the process.
2. gateway/run.py:_launch_systemd_restart_shortcut hardcoded
`--user` scope, so it could not even locate the unit PID on
system-level deployments (the common case for
/etc/systemd/system/hermes-gateway.service). It silently returned
without launching the helper.
3. Even after the scope detection was fixed, the helper could not
actually start: non-root gateway units (User=ubunutu) hit a Polkit
denial on `systemd-run --system` ("Interactive authentication
required"), and `--user` requires a D-Bus user session that is
typically absent on headless servers.
The fix is two-fold:
* `_stop_impl` now always exits with GATEWAY_SERVICE_RESTART_EXIT_CODE
(75 / EX_TEMPFAIL) on service-managed restarts, regardless of
platform. Combined with RestartForceExitStatus=75 in the unit file,
systemd treats the planned restart as a controlled failure and
revives the gateway via Restart=on-failure, with RestartSec as the
only delay. The planned-restart helper is still attempted (for
RestartSec=0 setups that want sub-second restarts) but is no longer
load-bearing.
* `_launch_systemd_restart_shortcut` now probes both system and user
scopes via MainPID equality and uses whichever scope actually owns
the gateway process. It bails out safely if neither matches.
StartLimitBurst in the unit file still bounds accidental restart
loops, and the macOS launchd path is unchanged.
Verified end-to-end on Ubuntu 24.04 with hermes-gateway as a
/etc/systemd/system/... service running under User=ubunutu. The
unit uses Restart=on-failure, RestartSec=30, RestartForceExitStatus=75,
StartLimitIntervalSec=600, StartLimitBurst=5. /restart from Feishu now
drains cleanly, exits 75, and the gateway is back online ~30s later
without manual intervention.
Tests: tests/gateway/test_gateway_shutdown.py renamed the affected
case to test_gateway_stop_systemd_service_restart_uses_tempfail and
now asserts exit_code == GATEWAY_SERVICE_RESTART_EXIT_CODE.
14/14 tests in this module pass.
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