Phase 3 of the s6-overlay supervision plan. Implements the runtime-
registration surface from D4 — only the s6 backend supports
register_profile_gateway / unregister_profile_gateway /
list_profile_gateways; host backends continue to raise
NotImplementedError. No caller yet (Phase 4 wires in the profile
create/delete hooks).
Key implementation notes:
- Service directory shape: /run/service/gateway-<profile>/{type,run,log/run}.
Atomic register: write to gateway-<profile>.tmp, fsync via
os.rename. Cleanup on rescan failure.
- Run script uses #!/command/with-contenv sh so HERMES_HOME and any
extra_env arrive at exec time. The hermes -p <profile> gateway
start --foreground --port <port> command is wrapped in
s6-setuidgid hermes for the per-service privilege drop (OQ2-A).
- Log script (OQ8-C): persists via s6-log to
${HERMES_HOME}/logs/gateways/<profile>/. CRITICAL — HERMES_HOME is
a runtime env-var expansion in the rendered script, NOT a Python
f-string substitution. Negative-asserted in
test_s6_register_creates_service_dir_and_triggers_scan so
regressions are caught.
- PATH gotcha: /command/ is only on PATH for processes spawned by
the supervision tree (services, cont-init.d). `docker exec` and
profile-create hooks don't get it. S6ServiceManager calls all
s6-* binaries via absolute path through the new _S6_BIN_DIR
constant so callers don't have to fix up env vars.
- validate_profile_name rejects path-traversal, leading-dash (s6
would parse as a flag), uppercase, whitespace, and names >251
chars (s6-svscan default name_max).
Test coverage:
- 13 new unit tests in tests/hermes_cli/test_service_manager.py
(kind detection, run-script content, env quoting, register
rollback on rescan failure, unregister idempotence, list filter,
lifecycle dispatch, svstat parsing). Total: 36 passing.
- 2 new in-container integration tests in
tests/docker/test_s6_profile_gateway_integration.py validating
end-to-end registration against a real s6 supervision tree.
Docker harness: 14 passed, 2 xfailed (Phase 4 target unchanged).
Refs: docs/plans/2026-05-07-s6-overlay-dynamic-subagent-gateways.md
Phase 1 of the s6-overlay supervision plan. Pure-refactor addition:
introduces the abstract interface (with runtime_checkable Protocol),
detect_service_manager(), validate_profile_name(), and thin
SystemdServiceManager / LaunchdServiceManager / WindowsServiceManager
wrappers around the existing systemd_* / launchd_* / gateway_windows.*
module-level functions. No host call site was modified — host code
continues to use the existing functions directly; the protocol is for
new backend-agnostic code (Phase 4 profile create/delete hooks and the
Phase 4 s6 dispatch path in 'hermes gateway start/stop/restart').
WindowsServiceManager.install() forwards the v3 kwargs (start_now,
start_on_login, elevated_handoff) added in PRs #28169-adjacent so
non-Windows callers — there aren't any today — can opt in.
The s6 backend lands in Phase 3; until then get_service_manager()
raises a clear error if invoked on a host that detects as 's6'.
