From 6cf57c676550068a59149ca82d63fcb5b5431158 Mon Sep 17 00:00:00 2001
From: Eugen Rochko <eugen@zeonfederated.com>
Date: Fri, 13 May 2022 00:02:35 +0200
Subject: Refactor how Redis locks are created (#18400)

* Refactor how Redis locks are created

* Fix autorelease duration on account deletion lock
---
 app/lib/activitypub/activity.rb          | 17 +----------------
 app/lib/activitypub/activity/announce.rb |  2 +-
 app/lib/activitypub/activity/create.rb   |  4 ++--
 app/lib/activitypub/activity/delete.rb   |  6 +++---
 4 files changed, 7 insertions(+), 22 deletions(-)

(limited to 'app/lib')

diff --git a/app/lib/activitypub/activity.rb b/app/lib/activitypub/activity.rb
index 3c51a7a51df..7ff06ea390c 100644
--- a/app/lib/activitypub/activity.rb
+++ b/app/lib/activitypub/activity.rb
@@ -3,6 +3,7 @@
 class ActivityPub::Activity
   include JsonLdHelper
   include Redisable
+  include Lockable
 
   SUPPORTED_TYPES = %w(Note Question).freeze
   CONVERTED_TYPES = %w(Image Audio Video Article Page Event).freeze
@@ -157,22 +158,6 @@ class ActivityPub::Activity
     end
   end
 
-  def lock_or_return(key, expire_after = 2.hours.seconds)
-    yield if redis.set(key, true, nx: true, ex: expire_after)
-  ensure
-    redis.del(key)
-  end
-
-  def lock_or_fail(key, expire_after = 15.minutes.seconds)
-    RedisLock.acquire({ redis: redis, key: key, autorelease: expire_after }) do |lock|
-      if lock.acquired?
-        yield
-      else
-        raise Mastodon::RaceConditionError
-      end
-    end
-  end
-
   def fetch?
     !@options[:delivery]
   end
diff --git a/app/lib/activitypub/activity/announce.rb b/app/lib/activitypub/activity/announce.rb
index 0674b108337..0032f13e623 100644
--- a/app/lib/activitypub/activity/announce.rb
+++ b/app/lib/activitypub/activity/announce.rb
@@ -4,7 +4,7 @@ class ActivityPub::Activity::Announce < ActivityPub::Activity
   def perform
     return reject_payload! if delete_arrived_first?(@json['id']) || !related_to_local_activity?
 
-    lock_or_fail("announce:#{@object['id']}") do
+    with_lock("announce:#{@object['id']}") do
       original_status = status_from_object
 
       return reject_payload! if original_status.nil? || !announceable?(original_status)
diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 1f32d8cce84..73882e1348f 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -47,7 +47,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
   def create_status
     return reject_payload! if unsupported_object_type? || invalid_origin?(object_uri) || tombstone_exists? || !related_to_local_activity?
 
-    lock_or_fail("create:#{object_uri}") do
+    with_lock("create:#{object_uri}") do
       return if delete_arrived_first?(object_uri) || poll_vote?
 
       @status = find_existing_status
@@ -315,7 +315,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     poll = replied_to_status.preloadable_poll
     already_voted = true
 
-    lock_or_fail("vote:#{replied_to_status.poll_id}:#{@account.id}") do
+    with_lock("vote:#{replied_to_status.poll_id}:#{@account.id}") do
       already_voted = poll.votes.where(account: @account).exists?
       poll.votes.create!(account: @account, choice: poll.options.index(@object['name']), uri: object_uri)
     end
diff --git a/app/lib/activitypub/activity/delete.rb b/app/lib/activitypub/activity/delete.rb
index f5ef863f37f..871eb39667a 100644
--- a/app/lib/activitypub/activity/delete.rb
+++ b/app/lib/activitypub/activity/delete.rb
@@ -12,7 +12,7 @@ class ActivityPub::Activity::Delete < ActivityPub::Activity
   private
 
   def delete_person
-    lock_or_return("delete_in_progress:#{@account.id}") do
+    with_lock("delete_in_progress:#{@account.id}", autorelease: 2.hours, raise_on_failure: false) do
       DeleteAccountService.new.call(@account, reserve_username: false, skip_activitypub: true)
     end
   end
@@ -20,14 +20,14 @@ class ActivityPub::Activity::Delete < ActivityPub::Activity
   def delete_note
     return if object_uri.nil?
 
-    lock_or_return("delete_status_in_progress:#{object_uri}", 5.minutes.seconds) do
+    with_lock("delete_status_in_progress:#{object_uri}", raise_on_failure: false) do
       unless invalid_origin?(object_uri)
         # This lock ensures a concurrent `ActivityPub::Activity::Create` either
         # does not create a status at all, or has finished saving it to the
         # database before we try to load it.
         # Without the lock, `delete_later!` could be called after `delete_arrived_first?`
         # and `Status.find` before `Status.create!`
-        lock_or_fail("create:#{object_uri}") { delete_later!(object_uri) }
+        with_lock("create:#{object_uri}") { delete_later!(object_uri) }
 
         Tombstone.find_or_create_by(uri: object_uri, account: @account)
       end
-- 
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