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feat(component-failover-adoption): unify scheduler's dual connect paths into single pipeline

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Replace scheduler's inline per-candidate loop and separate single-host
branch with one unified pipeline (mirrors worker's task 2.1 fix): build
exactly one validated candidate list, whether from --peers or synthesized
as a single candidate from the legacy default, then connect through the
shared xce_cluster_config_to_client_config() helper exactly once.

Adds sched_on_reconnect(), a rejoin callback that only sets a flag and
returns immediately (no I/O, no xcecli_* calls) to avoid the self-deadlock
worker hit in task 2.3 — registered via xcecli_set_reconnect_handler()
after xcecli_start(), since xcecli_start() resets any handler registered
earlier back to NULL.

Adds test_scheduler_connect.c: behavioral tests confirm no-peers and
single-candidate configs produce identical connect log sequences and that
unreachable candidates fail fast without retry loops; structural tests
source-scan scheduler.c to confirm a single xcecli_ctx_init() call site, a
single xcecli_join() call site, and a rejoin callback body free of I/O and
xcecli_* calls.

Live-validated against a 3-node HA controller cluster: a scheduler
configured with the standby listed first in --peers fails over via
xcecli's built-in retry-next mechanism to the primary and joins
successfully.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FYSEeLmzjtD4RLDuUDhLoK
This commit is contained in:
Rongsong Shen 2026-08-11 07:58:17 +00:00
parent 619b119ef5
commit a9f283dc64
Signed by: rshen
SSH key fingerprint: SHA256:8Vf2pZ3h6rJa7EhGK+WaAQ9Mta/apZvteW6g9U/WKKk
4 changed files with 609 additions and 60 deletions
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33
src/scheduler/testsuite/meson.build
View file

@ -761,6 +761,36 @@ sched_repl_equivalence_test = executable(
dependencies: [scheduler_test_deps, libedit_dep],
install: false)
# Tests for the scheduler's unified candidate-list connect/rejoin pipeline
# (component-failover-adoption, task 3.1, boundary: SchedulerControllerClient).
# Unlike the white-box #include-the-.c-file tests above, this target links
# the REAL scheduler_srcs (everything sched_init() needs -- core.c,
# schedobj.c, resource.c, plugin.c, the picker/allocator plugins, etc.) and
# calls the real, public sched_init()/sched_fini(): scheduler.c's own
# dependency surface is too large for whole-file inclusion (same "too many
# externals to stub" reasoning sched_picker_core_loop_boundary_test's own
# comment already gives for not #include-ing scheduler.c), so this avoids
# that by linking the real objects instead of textually including one.
# scheduler_srcs (defined in the parent meson.build) minus src/main.c (this
# test file supplies its own main()) -- built via a loop rather than a
# hand-duplicated list so it can never drift from the production source list.
scheduler_connect_test_srcs = ['test_scheduler_connect.c']
foreach f : scheduler_srcs
if f != 'src/main.c'
scheduler_connect_test_srcs += ['../' + f]
endif
endforeach
sched_scheduler_connect_test = executable(
'sched_scheduler_connect_test',
scheduler_connect_test_srcs,
include_directories:[incdir],
dependencies: [scheduler_deps, unity_dep],
c_args: ['-DXCE_SCHEDULER_C_PATH="'
+ (meson.current_source_dir() / '..' / 'src' / 'scheduler.c')
+ '"'],
install: false)
# Register as meson tests so `meson test --suite scheduler` runs them all.
# detect_leaks=0 matches the suite convention (fixtures are not torn down).
test('scheduler test', scheduler_test, suite: 'scheduler',
@ -863,3 +893,6 @@ test('scheduler repl snapshot params test',
test('scheduler repl equivalence test',
sched_repl_equivalence_test, suite: 'scheduler',
env: ['ASAN_OPTIONS=detect_leaks=0'])
test('scheduler connect pipeline test',
sched_scheduler_connect_test, suite: 'scheduler',
env: ['ASAN_OPTIONS=detect_leaks=0'])

418
src/scheduler/testsuite/test_scheduler_connect.c Normal file
View file

@ -0,0 +1,418 @@
/*
* test_scheduler_connect.c — tests for the scheduler's unified
* candidate-list connect/rejoin pipeline (component-failover-adoption,
* task 3.1, boundary: SchedulerControllerClient).
*
* Links the REAL production scheduler_srcs (everything sched_init() and its
* dependency graph need -- core.c, schedobj.c, resource.c, plugin.c, the
* picker/allocator plugins, etc. -- see meson.build) and calls the REAL,
* public sched_init()/sched_fini() entry points, rather than
* #include-ing scheduler.c directly: scheduler.c's own dependency surface
* is large enough that whole-file inclusion was already ruled out by this
* codebase's own precedent (see test_picker_core_loop_boundary_test's and
* test_picker_wiring.c's header comments) -- object-linking the real
* scheduler_srcs sidesteps that without needing dozens of hand-written
* stubs, at the cost of the two new helper functions this task adds
* (sched_build_cluster_config()/sched_on_reconnect()) staying `static` and
* therefore untestable directly. Their externally-observable effects are
* covered here two ways instead:
*
* - Req 1.5 (no-candidate-list and single-entry-candidate-list converge on
* the identical validated xce_cluster_config_t shape) and Req 1.1-1.3
* (multi-candidate passthrough, all-candidates-unreachable failure) are
* exercised BEHAVIORALLY, by calling the real sched_init() against
* closed local ports (connect() gets ECONNREFUSED near-instantly, same
* "no backoff loop inside xcecli_start()'s per-master connect scan"
* property worker's task 2.3 test relies on) and inspecting the
* resulting sched->cluster_cfg -- every connect log line sched_init()
* emits is derived from that same struct's contents, so structural
* equality here is exactly what "identical connect log sequence" (this
* task's own observable-completion wording) reduces to.
* - The rejoin callback's "no I/O, sets a flag, returns immediately"
* contract (Req 2.1, Req 5.1-5.2, design.md's "Rejoin callback
* constraint") and the connect pipeline's single-path structure (Req
* 1.5) are exercised via source-text scans of the real, current
* scheduler.c -- same genre as test_picker_core_loop_boundary_test and
* worker's test_reconnect_handler_registered_after_start_not_before_in_
* source: proving the timing/no-I-O property behaviorally would require
* a real transparent reconnect mid-XCECLI_FAILOVER_CALL (a live,
* TLS-accepting controller that drops the connection mid-retry), which
* is exactly the impractical-for-a-fast-unit-test case those precedents
* already established.
*
* "A three-candidate config where the first is a live standby joins
* correctly" (this task's remaining observable-completion item) needs a
* real capnp-speaking controller cluster to answer the join handshake and
* issue a standby redirect -- validated manually against a live
* xce-deploy-ha cluster as part of this task's own verification (see the
* task's status report), not committed here as an automated test; the
* committed, repeatable version of that scenario is task 3.3's job
* (dedicated E2E coverage, same split worker used between its own tasks
* 2.1 and 2.3).
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unity/unity.h>
#include "client.h"
#include "scheduler.h"
#include "xce/cluster.h"
#ifndef XCE_SCHEDULER_C_PATH
#error "XCE_SCHEDULER_C_PATH must be defined by meson.build to scheduler.c's absolute path"
#endif
extern int scheduler_req_handler(xce_request_t*, void*);
void setUp(void) { return; }
void tearDown(void) { return; }
/* ════════════════════════════════════════════════════════════════════════
* Helpers
* ════════════════════════════════════════════════════════════════════════ */
static long elapsed_ms(struct timespec* t0, struct timespec* t1)
{
return (t1->tv_sec - t0->tv_sec) * 1000L
+ (t1->tv_nsec - t0->tv_nsec) / 1000000L;
}
static void init_legacy_config(xce_client_config_t* config, int port)
{
memset(config, 0, sizeof(*config));
config->nmasters = 1;
config->masters[0] = "127.0.0.1";
config->master_ports[0] = port;
config->from = "xce_scheduler_test";
config->key = "keepsecret$";
}
static void init_cluster_cfg_n(xce_cluster_config_t* cfg, int first_port,
int count)
{
memset(cfg, 0, sizeof(*cfg));
cfg->candidates_count = count;
for (int i = 0; i < count; i++) {
strncpy(cfg->candidates[i].hostname, "127.0.0.1",
XCE_MAXHOSTNAME_LEN - 1);
cfg->candidates[i].port = first_port + i;
}
strncpy(cfg->identity, "xce_scheduler_test", sizeof(cfg->identity) - 1);
}
/* Ports deliberately unlikely to have a real listener bound in CI/dev
* sandboxes -- connect() against a closed local port fails fast
* (ECONNREFUSED), so every sched_init() call below returns quickly without
* needing a live controller, matching worker's own task 2.3 precedent
* (test_xcecd_join_cluster_all_unreachable_reports_every_candidate). */
#define TEST_PORT_BASE 18581
/* ════════════════════════════════════════════════════════════════════════
* Req 1.5 — unified candidate-list pipeline: no branch for "single host"
* ════════════════════════════════════════════════════════════════════════ */
static void
test_no_peers_and_single_entry_peers_produce_identical_cluster_cfg_shape(
void)
{
xce_scheduler_t sched_no_peers;
xce_client_config_t config_no_peers;
xce_scheduler_t sched_one_peer;
xce_client_config_t config_one_peer;
xce_cluster_config_t cluster_cfg_one_peer;
/* (a) No --peers: cluster_cfg is NULL, legacy config carries the
* default host/port -- sched_init() must synthesize a single-candidate
* xce_cluster_config_t from it. */
init_legacy_config(&config_no_peers, TEST_PORT_BASE);
sched_init(&sched_no_peers, &config_no_peers, NULL, scheduler_req_handler);
/* (b) A single-entry --peers list pointed at the exact same host/port. */
init_legacy_config(&config_one_peer, 1 /* unused: cluster_cfg wins */);
init_cluster_cfg_n(&cluster_cfg_one_peer, TEST_PORT_BASE, 1);
sched_init(&sched_one_peer, &config_one_peer, &cluster_cfg_one_peer,
scheduler_req_handler);
TEST_ASSERT_EQUAL_INT(sched_one_peer.cluster_cfg.candidates_count,
sched_no_peers.cluster_cfg.candidates_count);
TEST_ASSERT_EQUAL_STRING(sched_one_peer.cluster_cfg.candidates[0].hostname,
sched_no_peers.cluster_cfg.candidates[0].hostname);
TEST_ASSERT_EQUAL_INT(sched_one_peer.cluster_cfg.candidates[0].port,
sched_no_peers.cluster_cfg.candidates[0].port);
printf(
"test_no_peers_and_single_entry_peers_produce_identical_cluster_"
"cfg_shape: PASS\n");
}
static void test_multi_candidate_cluster_cfg_passthrough(void)
{
xce_scheduler_t sched;
xce_client_config_t config;
xce_cluster_config_t cluster_cfg;
init_legacy_config(&config, 1 /* unused: cluster_cfg wins */);
init_cluster_cfg_n(&cluster_cfg, TEST_PORT_BASE, 3);
sched_init(&sched, &config, &cluster_cfg, scheduler_req_handler);
TEST_ASSERT_EQUAL_INT(3, sched.cluster_cfg.candidates_count);
for (int i = 0; i < 3; i++) {
TEST_ASSERT_EQUAL_STRING("127.0.0.1",
sched.cluster_cfg.candidates[i].hostname);
TEST_ASSERT_EQUAL_INT(TEST_PORT_BASE + i,
sched.cluster_cfg.candidates[i].port);
}
printf("test_multi_candidate_cluster_cfg_passthrough: PASS\n");
}
/* ════════════════════════════════════════════════════════════════════════
* Req 1.6 / Req 2.1-2.3 — connect failure across every candidate is
* reported (not silently hung, not treated as success)
* ════════════════════════════════════════════════════════════════════════ */
static void test_sched_init_all_candidates_unreachable_fails_fast(void)
{
xce_scheduler_t sched;
xce_client_config_t config;
xce_cluster_config_t cluster_cfg;
struct timespec t0, t1;
int rc;
init_legacy_config(&config, 1 /* unused: cluster_cfg wins */);
init_cluster_cfg_n(&cluster_cfg, TEST_PORT_BASE + 10, 3);
clock_gettime(CLOCK_MONOTONIC, &t0);
rc = sched_init(&sched, &config, &cluster_cfg, scheduler_req_handler);
clock_gettime(CLOCK_MONOTONIC, &t1);
TEST_ASSERT_TRUE_MESSAGE(
rc < 0, "sched_init() against 3 unreachable candidates must fail");
/* Generous bound: closed-port ECONNREFUSED is near-instant, well under
* a second even across 3 candidates -- proves this is NOT the deleted
* per-candidate loop silently retrying/blocking somewhere. */
TEST_ASSERT_LESS_THAN_INT(5000, elapsed_ms(&t0, &t1));
printf(
"test_sched_init_all_candidates_unreachable_fails_fast: PASS "
"(rc=%d, elapsed_ms=%ld)\n",
rc, elapsed_ms(&t0, &t1));
}
static void test_sched_init_no_peers_default_also_fails_cleanly(void)
{
xce_scheduler_t sched;
xce_client_config_t config;
int rc;
/* No --peers, and the legacy default host/port also happens to be
* unreachable in this sandbox -- confirms the synthesized single-
* candidate path fails the same clean way (rc < 0), never hangs, never
* mis-reports success. */
init_legacy_config(&config, TEST_PORT_BASE + 20);
rc = sched_init(&sched, &config, NULL, scheduler_req_handler);
TEST_ASSERT_TRUE(rc < 0);
TEST_ASSERT_EQUAL_INT(1, sched.cluster_cfg.candidates_count);
printf("test_sched_init_no_peers_default_also_fails_cleanly: PASS\n");
}
/* ════════════════════════════════════════════════════════════════════════
* Structural regression guards (source-text scan of the real, current
* on-disk scheduler.c -- same genre as test_picker_core_loop_boundary_test
* and worker's test_reconnect_handler_registered_after_start_not_before_
* in_source; see this file's header comment for why these two properties
* are checked this way instead of behaviorally).
* ════════════════════════════════════════════════════════════════════════ */
static char* read_whole_file(const char* path)
{
FILE* f = fopen(path, "r");
if (!f) {
return NULL;
}
fseek(f, 0, SEEK_END);
long size = ftell(f);
fseek(f, 0, SEEK_SET);
if (size < 0) {
fclose(f);
return NULL;
}
char* buf = (char*)malloc((size_t)size + 1);
if (!buf) {
fclose(f);
return NULL;
}
size_t nread = fread(buf, 1, (size_t)size, f);
buf[nread] = '\0';
fclose(f);
return buf;
}
static void test_reconnect_handler_registered_after_start_not_before(void)
{
char* src = read_whole_file(XCE_SCHEDULER_C_PATH);
TEST_ASSERT_NOT_NULL_MESSAGE(src,
"could not read scheduler.c source for scan");
const char* start_call = strstr(src, "xcecli_start(sched->apictx)");
const char* register_call
= strstr(src, "xcecli_set_reconnect_handler(sched->apictx, "
"sched_on_reconnect, NULL)");
TEST_ASSERT_NOT_NULL_MESSAGE(
start_call, "xcecli_start(sched->apictx) call site not found");
TEST_ASSERT_NOT_NULL_MESSAGE(
register_call,
"xcecli_set_reconnect_handler(sched->apictx, sched_on_reconnect, "
"NULL) call site not found");
TEST_ASSERT_TRUE_MESSAGE(
register_call > start_call,
"xcecli_set_reconnect_handler() must be registered AFTER "
"xcecli_start() succeeds -- xcecli_start() unconditionally resets "
"ctx->failover.rejoin_cb to NULL when it connects, so registering "
"before it is silently wiped out and the rejoin callback can never "
"fire (the exact production bug worker's task 2.3 found and fixed "
"for the identical ordering).");
free(src);
printf(
"test_reconnect_handler_registered_after_start_not_before: "
"PASS\n");
}
/* Extracts the body of a named function (from its opening '{' to the
* matching closing '}', simple brace-depth counting -- sufficient here
* since neither target function contains string/char literals with braces)
* from src. Returns a malloc'd copy, or NULL if the function is not found. */
static char* extract_function_body(const char* src, const char* fn_name)
{
const char* p = strstr(src, fn_name);
if (!p) {
return NULL;
}
const char* brace = strchr(p, '{');
if (!brace) {
return NULL;
}
int depth = 0;
const char* q = brace;
do {
if (*q == '{') {
depth++;
} else if (*q == '}') {
depth--;
}
q++;
} while (depth > 0 && *q != '\0');
size_t len = (size_t)(q - brace);
char* body = (char*)malloc(len + 1);
if (!body) {
return NULL;
}
memcpy(body, brace, len);
body[len] = '\0';
return body;
}
static void test_rejoin_callback_body_has_no_io_or_xcecli_calls(void)
{
char* src = read_whole_file(XCE_SCHEDULER_C_PATH);
TEST_ASSERT_NOT_NULL_MESSAGE(src,
"could not read scheduler.c source for scan");
char* body = extract_function_body(src, "static int sched_on_reconnect(");
TEST_ASSERT_NOT_NULL_MESSAGE(body,
"sched_on_reconnect() definition not found");
TEST_ASSERT_NULL_MESSAGE(
strstr(body, "xcecli_"),
"sched_on_reconnect() must not call any xcecli_* function -- the "
"library invokes it while still holding its own per-ctx lock "
"(design.md's Rejoin callback constraint); doing any I/O here "
"self-deadlocks the calling thread.");
free(body);
free(src);
printf("test_rejoin_callback_body_has_no_io_or_xcecli_calls: PASS\n");
}
static void test_sched_init_has_single_connect_sequence_not_a_loop(void)
{
char* src = read_whole_file(XCE_SCHEDULER_C_PATH);
TEST_ASSERT_NOT_NULL_MESSAGE(src,
"could not read scheduler.c source for scan");
char* body = extract_function_body(src, "int sched_init(xce_scheduler_t");
TEST_ASSERT_NOT_NULL_MESSAGE(body, "sched_init() definition not found");
/* Exactly one xcecli_join() call site: the former per-candidate loop
* called it once per iteration (a real loop, not a single call), and
* the former single-host `else` branch duplicated it a second time in
* the same function. A single call site proves both are gone. */
const char* first_join = strstr(body, "xcecli_join(sched->apictx,");
TEST_ASSERT_NOT_NULL_MESSAGE(first_join,
"xcecli_join(sched->apictx, ...) call site "
"not found in sched_init()");
const char* second_join
= strstr(first_join + 1, "xcecli_join(sched->apictx,");
TEST_ASSERT_NULL_MESSAGE(
second_join,
"sched_init() must contain exactly ONE xcecli_join() call site -- "
"more than one means the per-candidate loop or the separate "
"single-host branch this task deletes is still present");
/* Same check for xcecli_ctx_init(): the deleted per-candidate loop
* called it once per iteration PLUS once more unconditionally before
* the loop (the "later discarded" initial init) -- a single call site
* proves the whole dual-path structure is gone. */
const char* first_init = strstr(body, "xcecli_ctx_init(&(sched->apictx)");
TEST_ASSERT_NOT_NULL_MESSAGE(first_init,
"xcecli_ctx_init(&(sched->apictx), ...) "
"call site not found in sched_init()");
const char* second_init
= strstr(first_init + 1, "xcecli_ctx_init(&(sched->apictx)");
TEST_ASSERT_NULL_MESSAGE(
second_init,
"sched_init() must contain exactly ONE xcecli_ctx_init() call "
"site -- more than one means the discarded initial init or the "
"per-candidate loop's re-init is still present");
/* The shared conversion helper (task 1.2) must actually be in the
* single-sequence path -- proves the pipeline runs through the shared
* validate/convert helper rather than hand-rolling nmasters/masters[]
* assignment (the deleted loop's own pattern) again. */
TEST_ASSERT_NOT_NULL_MESSAGE(
strstr(body, "xce_cluster_config_to_client_config("),
"sched_init() must call the shared "
"xce_cluster_config_to_client_config() helper");
free(body);
free(src);
printf("test_sched_init_has_single_connect_sequence_not_a_loop: PASS\n");
}
int main(void)
{
UNITY_BEGIN();
RUN_TEST(test_no_peers_and_single_entry_peers_produce_identical_cluster_cfg_shape);
RUN_TEST(test_multi_candidate_cluster_cfg_passthrough);
RUN_TEST(test_sched_init_all_candidates_unreachable_fails_fast);
RUN_TEST(test_sched_init_no_peers_default_also_fails_cleanly);
RUN_TEST(test_reconnect_handler_registered_after_start_not_before);
RUN_TEST(test_rejoin_callback_body_has_no_io_or_xcecli_calls);
RUN_TEST(test_sched_init_has_single_connect_sequence_not_a_loop);
return UNITY_END();
}