SSR health: alert mails on ok/down transitions + auto-failover to SPA after N consecutive misses (SSR_ALERT_EMAIL / SSR_FAILOVER_AFTER in var/vitec-ssr-purge.env)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/vitec/Classes/Service/SsrPurgeService.php

@@ -13,7 +13,8 @@ use TYPO3\CMS\Core\Http\RequestFactory;
  * keeps a log of every attempt in tx_vitec_ssrpurgelog.
  *
  * Endpoint + secret live OUTSIDE the repository in var/vitec-ssr-purge.env
- * (KEY=VALUE lines: SSR_PURGE_ENDPOINT, SSR_PURGE_SECRET, SSR_HEALTH_ENDPOINT)
+ * (KEY=VALUE lines: SSR_PURGE_ENDPOINT, SSR_PURGE_SECRET, SSR_HEALTH_ENDPOINT,
+ * SSR_ALERT_EMAIL, SSR_FAILOVER_AFTER)
  * - same pattern as the routing flag file, nothing secret in git.
  */
 final class SsrPurgeService
@@ -41,6 +42,25 @@ final class SsrPurgeService
         return $this->getConfig()['SSR_HEALTH_ENDPOINT'] ?? '';
     }
 
+    /**
+     * Comma-separated recipient list for vitec:ssr-health transition and
+     * failover alerts (SSR_ALERT_EMAIL); empty string = alerting off.
+     */
+    public function getAlertEmail(): string
+    {
+        return trim($this->getConfig()['SSR_ALERT_EMAIL'] ?? '');
+    }
+
+    /**
+     * Consecutive DOWN samples after which vitec:ssr-health fails over to
+     * the SPA (SSR_FAILOVER_AFTER, default 2 = ~10 minutes at the 5-minute
+     * cron cadence). Never below 1.
+     */
+    public function getFailoverAfter(): int
+    {
+        return max(1, (int)($this->getConfig()['SSR_FAILOVER_AFTER'] ?? 2));
+    }
+
     /**
      * Normalizes, dedupes and sends the paths; logs the outcome.
      * Never throws - editors' saves must not fail on a purge problem.