Change feed merge, unmerge and regeneration workers to use a replica (#25849)

app/workers/merge_worker.rb

@@ -5,7 +5,14 @@ class MergeWorker
   include Redisable
 
   def perform(from_account_id, into_account_id)
-    FeedManager.instance.merge_into_home(Account.find(from_account_id), Account.find(into_account_id))
+    ApplicationRecord.connected_to(role: :primary) do
+      @from_account = Account.find(from_account_id)
+      @into_account = Account.find(into_account_id)
+    end
+
+    ApplicationRecord.connected_to(role: :read, prevent_writes: true) do
+      FeedManager.instance.merge_into_home(@from_account, @into_account)
+    end
   rescue ActiveRecord::RecordNotFound
     true
   ensure

app/workers/regeneration_worker.rb

@@ -6,8 +6,13 @@ class RegenerationWorker
   sidekiq_options lock: :until_executed
 
   def perform(account_id, _ = :home)
-    account = Account.find(account_id)
-    PrecomputeFeedService.new.call(account)
+    ApplicationRecord.connected_to(role: :primary) do
+      @account = Account.find(account_id)
+    end
+
+    ApplicationRecord.connected_to(role: :read, prevent_writes: true) do
+      PrecomputeFeedService.new.call(@account)
+    end
   rescue ActiveRecord::RecordNotFound
     true
   end

app/workers/unmerge_worker.rb

@@ -6,7 +6,14 @@ class UnmergeWorker
   sidekiq_options queue: 'pull'
 
   def perform(from_account_id, into_account_id)
-    FeedManager.instance.unmerge_from_home(Account.find(from_account_id), Account.find(into_account_id))
+    ApplicationRecord.connected_to(role: :primary) do
+      @from_account = Account.find(from_account_id)
+      @into_account = Account.find(into_account_id)
+    end
+
+    ApplicationRecord.connected_to(role: :read, prevent_writes: true) do
+      FeedManager.instance.unmerge_from_home(@from_account, @into_account)
+    end
   rescue ActiveRecord::RecordNotFound
     true
   end