- sem_timedwait on heartbeat_seen semaphore with CLOCK_REALTIME deadline
- deadline = now + election_timeout_ms + xorshift64 jitter
- Returns CTRL_STANDBY on heartbeat arrival (calls ha_do_demote)
- Returns CTRL_ELECTING on timeout (caller drives election)
- Allows OPCode_heartbeat through dispatch gate in CTRL_INIT state
- 3 new unit tests: standby-on-heartbeat, electing-on-timeout, gate-allows-heartbeat
- 24 Tests 0 Failures in test_ha_startup suite
- errnox.h: add E_XCE_NOT_READY and E_XCE_STANDBY error codes with
extern int XCE_ERR_NOT_READY / XCE_ERR_STANDBY runtime variables
- ha.h: declare ha_dispatch_gate(ha_state_t *, int opcode)
- ha.c: define XCE_ERR_* variables; initialize heartbeat_seen semaphore
and primary_ctrl_fd = -1 in ha_init(); sem_destroy in ha_fini();
implement ha_dispatch_gate() with allowlist for CTRL_INIT/CTRL_ELECTING
(only OP_requestVote and OP_probeConfigTag pass) and CTRL_STANDBY
(replication, election, and housekeeping ops pass; primary-only ops
return -XCE_ERR_STANDBY)
- cluster.c: wire ha_dispatch_gate() in myreq_handler() before opcode
switch; gate failure sends error reply and returns early
All 393 unit tests pass. Satisfies requirements 1.3 and 1.4.
- Add HA_DEFAULT_* constants to ha.h; use them in cluster_init()
- Strip stale task-label comments (P1-3a, P1-5, P1-6, P3-6 refs)
- Remove self-documenting 'Step N:' annotations from ha_do_promote/demote
- Rewrite stale forward-reference notes as current WHY comments
- Remove resolved TODO P0-8b from cluster.c
Add test-only function ha_trigger_manual_failover_for_test() to exercise manual
failover state machine (demote → promote cycle) without requiring live cluster_t.
Test coverage:
- test_manual_failover_transitions_role_and_increments_term: Validates role
transitions (PRIMARY → STANDBY → PRIMARY) and term monotonicity
- test_manual_failover_resets_hooks_registered: Confirms demotion resets the
hooks_registered idempotency guard
- test_manual_failover_monotonic_term_across_multiple_cycles: Validates term
remains monotonically increasing across 5 consecutive failover cycles
Implementation:
- Exposed only under #ifdef XCE_TESTING in ha.h
- Function body (6 lines): calls ha_do_demote() then ha_do_promote(); returns
the new term value via atomic_load_explicit()
- Enables design validation (P3-6) without test-cluster infrastructure
All tests pass. Build clean.
Add redirect helpers to ha.c/ha.h so a standby controller never accepts
join requests as if it were the primary:
- ha_should_redirect(): returns 1 when role is STANDBY and primary_host/port
are known — caller should send E_XCE_REDIRECT.
- ha_no_primary_known(): returns 1 when role is STANDBY but primary address
is not yet known — caller should send E_XCE_NOMASTER (retry later).
- Add E_XCE_NOMASTER and E_XCE_REDIRECT to errnox.h.
- Wire both guards into handle_join_() in join.c (before the role switch)
so all join types (worker, scheduler, apiserver, client) are protected.
- Full redirect response sends status=-E_XCE_REDIRECT with nodata body;
the primary host:port are logged so operators can trace misrouted clients.
Full Cap'n Proto RedirectInfo response body is deferred to a follow-up
(schema union would require regenerating capnp bindings).
5 new TDD tests — 110 total, 0 failures.
- ha_do_promote(): atomic_fetch_add term, set role=PRIMARY, reset
last_received_crc to WAL_CRC_NONE (COH-5 chain restart on promotion)
- ha_do_demote(): set role=STANDBY, reset hooks_registered idempotency guard
- ha_install_sigusr1(): sigaction handler stores only atomic int —
async-signal-safe per POSIX.1-2017 §2.4.3; global g_sigusr1_ha set
once before signals are enabled
- ha_promote_to_primary() / ha_demote_to_standby() remain (void)c stubs
pending P1-5 cluster wiring
Tests: 3 new cases in test_ha_role.c
test_promote_increments_term: term > term_before, role == PRIMARY
test_demote_sets_standby_role: role reverts to STANDBY after promote+demote
test_sigusr1_sets_failover_requested: raise(SIGUSR1) sets atomic flag
Result: 100 Tests 0 Failures 0 Ignored (controller suite)
- Add ha_start_watchdog() / ha_stop_watchdog() — dedicated pthread with
nanosleep(heartbeat_interval_ms) loop; stop via atomic watchdog_stop +
pthread_join (no pthread_cancel, safe for OpenSSL)
- Add ha_check_heartbeat_nocluster() — reads role with
atomic_load_explicit(memory_order_acquire), guards on primary_host[0]=='\0',
computes elapsed_ms from CLOCK_MONOTONIC, sets failover_requested on timeout
- Update ha_fini() to call ha_stop_watchdog() before mutex destroy
- 3 new tests (TDD RED→GREEN): watchdog starts/stops, no-op when no primary,
stale heartbeat no crash; all 97 controller tests green
- Full ha.h: ctrl_role_t enum (CTRL_PRIMARY/CTRL_STANDBY), ha_config_t,
ha_state_t with _Atomic fields (term, role, applied_lsn, promotion
counters, watchdog_stop), pthread_mutex_t lock, and public API.
- endpoint_t* omitted from ha_state_t — including netio.h would pull
OpenSSL headers and risk circular deps; watchdog (P1-3) includes
netio.h directly where needed.
- ha_init validates: heartbeat_interval_ms >= 2000, heartbeat_timeout_ms
>= heartbeat_interval_ms, election_timeout_ms >= 500; returns -EINVAL
on bad config; zeros struct and sets initial role to CTRL_STANDBY.
- ha_fini destroys mutex; watchdog thread join deferred to P1-3.
- am_i_primary / ha_promote_to_primary / ha_demote_to_standby are
no-op stubs; cluster_t->ha field not yet wired (P1-5), so these avoid
incomplete-type dereferences until then.
- TDD: 5 new tests in test_ha_role.c confirmed RED before implementation,
all 5 GREEN after; all prior controller tests remain green.
