From 68f3a554a73df8d077a4a7a4471c43956a0d1ab8 Mon Sep 17 00:00:00 2001
From: Ollie <oliver.hyde@wikimedia.de>
Date: Fri, 13 Feb 2026 16:44:34 +0000
Subject: [PATCH] Prevent `ElasticSearchAliasInit` jobs overlapping

Elasticsearch can only process cluster state changes, such as adding new aliases, sequentially on the master node. Runing multiple instances of this job (e.g. with the `EnsureElasticSearchAliases` command) can overload the Elasticsearch master node causing Jobs to fail.

Prevent multiple `ElasticSearchAliasInit` jobs from runing at the same time by using the `WithoutOverlapping` middleware [1]

[1]: https://laravel.com/docs/10.x/queues#preventing-job-overlaps

Bug: T416158
---
 app/Jobs/ElasticSearchAliasInit.php | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/app/Jobs/ElasticSearchAliasInit.php b/app/Jobs/ElasticSearchAliasInit.php
index 1bfc3c09..651448ad 100644
--- a/app/Jobs/ElasticSearchAliasInit.php
+++ b/app/Jobs/ElasticSearchAliasInit.php
@@ -5,6 +5,7 @@
 use App\Http\Curl\HttpRequest;
 use App\WikiDb;
 use Illuminate\Foundation\Bus\Dispatchable;
+use Illuminate\Queue\Middleware\WithoutOverlapping;
 use Illuminate\Support\Facades\Log;
 
 class ElasticSearchAliasInit extends Job {
@@ -24,6 +25,18 @@ public function __construct(int $wikiId, string $esHost, ?string $sharedPrefix =
         $this->sharedPrefix = $sharedPrefix ?? getenv('ELASTICSEARCH_SHARED_INDEX_PREFIX');
     }
 
+    /**
+     * Get the middleware the job should pass through.
+     *
+     * @return array<int, object>
+     */
+    public function middleware(): array {
+        return [
+            // Only allow one job per ES host to run at a time to avoid DoSing the ES cluster with alias updates
+            new WithoutOverlapping("elasticsearch-alias-init-{$this->esHost}"),
+        ];
+    }
+
     public function handle(HttpRequest $request) {
         Log::info(__METHOD__ . ": Updating Elasticsearch aliases for $this->wikiId");