From ce36f54dcd570145cd0d34be425692af1771c873 Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Mon, 5 Dec 2016 11:39:08 +0800
Subject: [PATCH] Add rake task to clean up orphane Redis keys when a multisite
 has been removed.

---
 lib/tasks/redis.rake | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 lib/tasks/redis.rake

diff --git a/lib/tasks/redis.rake b/lib/tasks/redis.rake
new file mode 100644
index 00000000000..4300f0686cb
--- /dev/null
+++ b/lib/tasks/redis.rake
@@ -0,0 +1,30 @@
+task 'redis:clean_up' => ['environment'] do
+  return unless Rails.configuration.multisite
+
+  dbs = RailsMultisite::ConnectionManagement.all_dbs
+  dbs << Discourse::SIDEKIQ_NAMESPACE
+
+  regexp = /((\$(?<message_bus>\w+)$)|(^?(?<namespace>\w+):))/
+
+  cursor = 0
+  redis = $redis.without_namespace
+
+  loop do
+    cursor, keys = redis.scan(cursor)
+    cursor = cursor.to_i
+
+    redis.multi do
+      keys.each do |key|
+        if match = key.match(regexp)
+          db_name = match[:message_bus] || match[:namespace]
+
+          if !dbs.include?(db_name)
+            redis.del(key)
+          end
+        end
+      end
+    end
+
+    break if cursor == 0
+  end
+end