SSR alert mail recipients maintainable in the site settings

New site setting vitec.ssr.alertEmails (Site Management, Settings, VITEC; one address per entry). vitec:ssr-health reads the recipients from there, invalid entries are skipped and logged, SSR_ALERT_EMAIL in the env file stays as fallback. The cockpit shows the recipients in the live band. Pre-filled with the address that was in the env file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/vitec/Classes/Service/SsrPurgeService.php

@@ -7,6 +7,8 @@ namespace Evomedien\Vitec\Service;
 use TYPO3\CMS\Core\Database\ConnectionPool;
 use TYPO3\CMS\Core\Core\Environment;
 use TYPO3\CMS\Core\Http\RequestFactory;
+use TYPO3\CMS\Core\Site\SiteFinder;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
 
 /**
  * Talks to the SSR node's POST /__purge endpoint (contract 0054-FE) and
@@ -24,6 +26,7 @@ final class SsrPurgeService
     public function __construct(
         private readonly RequestFactory $requestFactory,
         private readonly ConnectionPool $connectionPool,
+        private readonly SiteFinder $siteFinder,
     ) {}
 
     public static function getConfigPath(): string
@@ -66,6 +69,50 @@ final class SsrPurgeService
         return trim($this->getConfig()['SSR_ALERT_EMAIL'] ?? '');
     }
 
+    /**
+     * Who gets the vitec:ssr-health alert mails. Maintained by editors in
+     * Site Management › Settings › VITEC (vitec.ssr.alertEmails, one
+     * address per entry); the first site with at least one valid address
+     * wins. Without such a list, SSR_ALERT_EMAIL from the env file is the
+     * fallback. Invalid entries are skipped and reported back.
+     *
+     * @return array{recipients: list<string>, source: string, invalid: list<string>}
+     */
+    public function getAlertRecipients(): array
+    {
+        $invalid = [];
+        try {
+            foreach ($this->siteFinder->getAllSites() as $site) {
+                $list = $site->getSettings()->get('vitec.ssr.alertEmails', []);
+                if (is_string($list)) {
+                    $list = GeneralUtility::trimExplode(',', $list, true);
+                }
+                $valid = [];
+                foreach ((array)$list as $address) {
+                    $address = trim((string)$address);
+                    if ($address === '') {
+                        continue;
+                    }
+                    if (GeneralUtility::validEmail($address)) {
+                        $valid[] = $address;
+                    } else {
+                        $invalid[] = $address;
+                    }
+                }
+                if ($valid !== []) {
+                    return ['recipients' => array_values(array_unique($valid)), 'source' => 'site settings', 'invalid' => $invalid];
+                }
+            }
+        } catch (\Throwable) {
+            // No site configuration readable (e.g. broken YAML): use the env fallback.
+        }
+        $env = array_values(array_filter(
+            GeneralUtility::trimExplode(',', $this->getAlertEmail(), true),
+            static fn(string $a): bool => GeneralUtility::validEmail($a)
+        ));
+        return ['recipients' => $env, 'source' => $env !== [] ? 'var/vitec-ssr-purge.env' : '', 'invalid' => $invalid];
+    }
+
     /**
      * Consecutive DOWN samples after which vitec:ssr-health fails over to
      * the SPA (SSR_FAILOVER_AFTER, default 2 = ~10 minutes at the 5-minute