Schedule at most 100 commits

When processing push payloads we now schedule at most the 100 most
recent commits, instead of all commits that were in a payload. This
prevents one from overloading the system by pushing thousands if not
millions of commits in a single go.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/25827

1 files changed, 13 insertions, 11 deletions

diff --git a/app/services/git_push_service.rb b/app/services/git_push_service.rb
index 185556c12cc..6bbc3a9d9ff 100644
--- a/app/services/git_push_service.rb
+++ b/app/services/git_push_service.rb
@@ -3,6 +3,9 @@ class GitPushService < BaseService
   include Gitlab::CurrentSettings
   include Gitlab::Access
 
+  # The N most recent commits to process in a single push payload.
+  PROCESS_COMMIT_LIMIT = 100
+
   # This method will be called after each git update
   # and only if the provided user and project are present in GitLab.
   #
@@ -77,6 +80,16 @@ class GitPushService < BaseService
     ProjectCacheWorker.perform_async(@project.id, types)
   end
 
+  # Schedules processing of commit messages.
+  def process_commit_messages
+    default = is_default_branch?
+
+    push_commits.last(PROCESS_COMMIT_LIMIT).each do |commit|
+      ProcessCommitWorker.
+        perform_async(project.id, current_user.id, commit.to_hash, default)
+    end
+  end
+
   protected
 
   def execute_related_hooks
@@ -128,17 +141,6 @@ class GitPushService < BaseService
     end
   end
 
-  # Extract any GFM references from the pushed commit messages. If the configured issue-closing regex is matched,
-  # close the referenced Issue. Create cross-reference Notes corresponding to any other referenced Mentionables.
-  def process_commit_messages
-    default = is_default_branch?
-
-    @push_commits.each do |commit|
-      ProcessCommitWorker.
-        perform_async(project.id, current_user.id, commit.to_hash, default)
-    end
-  end
-
   def build_push_data
     @push_data ||= Gitlab::DataBuilder::Push.build(
       @project,