fix(daemons): reload the servers list on a 5-second timer

Once the signals daemon had run its first settings check, it called
ServerRepository::getAll(true) - a SELECT * FROM servers against MAIN - on
every pass of a loop that sleeps 250 ms: up to 240 reads a minute from every
node. The watchdog and the cache handler tied the reload to the settings
interval instead (10-60 s), so their view of the cluster could be a minute
stale.

DaemonTrait::serversRefreshDue()/refreshServers() reload at most every five
seconds, and the three daemons use it: 12 reads a minute, never more than
five seconds stale (SignalsLoopQueryRateTest). Phase 0 of the MAIN <-> LB
API plan.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Es8UhyPS8MNjuYTagqfGWi

src/Cli/Commands/CacheHandlerCommand.php

@@ -7,7 +7,6 @@ use XcVm\Cli\DaemonTrait;
 use XcVm\Core\Config\SettingsManager;
 use XcVm\Core\Config\SettingsRepository;
 use XcVm\Domain\Line\LineService;
-use XcVm\Domain\Server\ServerRepository;
 use XcVm\Infrastructure\Signal\SignalQueue;
 
 /**
@@ -58,9 +57,11 @@ class CacheHandlerCommand implements CommandInterface {
 				break;
 			}
 
+			if ($this->serversRefreshDue()) {
+				$this->refreshServers();
+			}
 			if ($this->shouldRefreshSettings()) {
 				SettingsManager::set(SettingsRepository::getAll(true));
-				ServerRepository::getAll(true);
 				if (!SettingsManager::get('enable_cache')) {
 					echo "Cache disabled! Break.\n";
 					break;

src/Cli/Commands/SignalsCommand.php

@@ -57,8 +57,10 @@ class SignalsCommand implements CommandInterface {
 			if (!$this->refreshOrBreak()) {
 				break;
 			}
-			if ($this->rLastCheck) {
-				$rServers = ServerRepository::getAll(true);
+			// Was every pass (four times a second): a `SELECT * FROM servers`
+			// against MAIN from every node, all day.
+			if ($this->serversRefreshDue()) {
+				$rServers = $this->refreshServers();
 			}
 
 			// Stop if Redis required but dead. checkRedisHealth() catches

src/Cli/Commands/WatchdogCommand.php

@@ -80,6 +80,10 @@ class WatchdogCommand implements CommandInterface {
 				$this->attemptRedisRestart();
 			}
 
+			if ($this->serversRefreshDue()) {
+				$rServers = $this->refreshServers();
+			}
+
 			if ($this->shouldRefreshSettings()) {
 				if (!ProcessManager::isNginxRunning()) {
 					echo "Not running! Break.\n";
@@ -89,7 +93,6 @@ class WatchdogCommand implements CommandInterface {
 					echo "File changed! Break.\n";
 					break;
 				}
-				$rServers = ServerRepository::getAll(true);
 				SettingsManager::set(SettingsRepository::getAll(true));
 				ConnectionTracker::getCapacity(true);
 				ConnectionTracker::getCapacity(false);

src/Cli/DaemonTrait.php

@@ -5,6 +5,7 @@ namespace XcVm\Cli;
 use XcVm\Core\Config\SettingsManager;
 use XcVm\Core\Config\SettingsRepository;
 use XcVm\Core\Process\ProcessManager;
+use XcVm\Domain\Server\ServerRepository;
 use XcVm\Infrastructure\Redis\RedisManager;
 
 /**
@@ -30,6 +31,9 @@ trait DaemonTrait {
 	/** @var int Интервал обновления настроек (секунды) */
 	protected $rRefreshInterval = 60;
 
+	/** @var int|null When the servers list was last reloaded from the DB. */
+	protected $rServersRefreshedAt = null;
+
 	/** @var resource|null Файловый lock для singleton-демона */
 	protected $rDaemonLockHandle;
 
@@ -74,6 +78,31 @@ trait DaemonTrait {
 	/**
 	 * Проверить нужно ли обновить настройки (по таймеру).
 	 */
+	/**
+	 * Reload the servers list at most this often. Often enough that routing,
+	 * ports and node state are never more than five seconds stale; rare
+	 * enough that a tight loop does not re-read `servers` on every pass.
+	 */
+	protected function serversRefreshInterval(): int {
+		return 5;
+	}
+
+	/** Is the servers list due for a reload? */
+	protected function serversRefreshDue(?int $rNow = null): bool {
+		return $this->rServersRefreshedAt === null
+			|| ($rNow ?? time()) - $this->rServersRefreshedAt >= $this->serversRefreshInterval();
+	}
+
+	/**
+	 * Reload the servers list from the DB (which also rewrites its cache).
+	 *
+	 * @return array<int, array<string, mixed>>
+	 */
+	protected function refreshServers(): array {
+		$this->rServersRefreshedAt = time();
+		return ServerRepository::getAll(true);
+	}
+
 	protected function shouldRefreshSettings(): bool {
 		return !$this->rLastCheck || $this->rRefreshInterval <= time() - $this->rLastCheck;
 	}

tests/Unit/SignalsLoopQueryRateTest.php

@@ -0,0 +1,61 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+use XcVm\Cli\DaemonTrait;
+
+/**
+ * The signals daemon re-read `servers` (a SELECT * against MAIN) on every
+ * pass of its loop once it had run a settings check — four times a second on
+ * every node. Persistent loops now reload the servers list on a five-second
+ * timer shared through DaemonTrait.
+ */
+final class SignalsLoopQueryRateTest extends TestCase {
+
+	private function daemon(): object {
+		return new class {
+			use DaemonTrait;
+
+			public function due(?int $rNow): bool {
+				return $this->serversRefreshDue($rNow);
+			}
+
+			public function markRefreshed(int $rAt): void {
+				$this->rServersRefreshedAt = $rAt;
+			}
+		};
+	}
+
+	public function testReloadAtMostEveryFiveSeconds(): void {
+		$rDaemon = $this->daemon();
+		$this->assertTrue($rDaemon->due(1000), 'first pass loads');
+		$rDaemon->markRefreshed(1000);
+		$this->assertFalse($rDaemon->due(1000));
+		$this->assertFalse($rDaemon->due(1004));
+		$this->assertTrue($rDaemon->due(1005));
+	}
+
+	public function testAQuarterSecondLoopReadsServersTwelveTimesAMinuteNotTwoHundredForty(): void {
+		$rDaemon = $this->daemon();
+		$rReads = 0;
+		for ($rTick = 0; $rTick < 240; $rTick++) { // one minute at usleep(250000)
+			$rNow = 1000 + intdiv($rTick, 4);
+			if ($rDaemon->due($rNow)) {
+				$rReads++;
+				$rDaemon->markRefreshed($rNow);
+			}
+		}
+		$this->assertSame(12, $rReads);
+	}
+
+	/** @dataProvider daemons */
+	public function testDaemonsUseTheTimer(string $rFile): void {
+		$rSource = (string) file_get_contents(dirname(__DIR__, 2) . '/src/Cli/Commands/' . $rFile);
+		$this->assertStringContainsString('$this->serversRefreshDue()', $rSource);
+		$this->assertStringNotContainsString('ServerRepository::getAll(true)', $rSource);
+	}
+
+	/** @return array<string, array{string}> */
+	public static function daemons(): array {
+		return ['signals' => ['SignalsCommand.php'], 'watchdog' => ['WatchdogCommand.php'], 'cache handler' => ['CacheHandlerCommand.php']];
+	}
+}