Prune web hook logs older than 90 days

This adds a recurring Sidekiq job that removes up to 50 000 old web hook
logs per hour, if they are older than 90 days. This will prevent the
web_hook_logs table from growing indefinitely.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/46120

app/workers/all_queues.yml

@@ -20,6 +20,7 @@
 - cronjob:ci_archive_traces_cron
 - cronjob:trending_projects
 - cronjob:issue_due_scheduler
+- cronjob:prune_web_hook_logs
 
 - gcp_cluster:cluster_install_app
 - gcp_cluster:cluster_provision

app/workers/prune_web_hook_logs_worker.rb

+# frozen_string_literal: true
+
+# Worker that deletes a fixed number of outdated rows from the "web_hook_logs"
+# table.
+class PruneWebHookLogsWorker
+  include ApplicationWorker
+  include CronjobQueue
+
+  # The maximum number of rows to remove in a single job.
+  DELETE_LIMIT = 50_000
+
+  def perform
+    # MySQL doesn't allow "DELETE FROM ... WHERE id IN ( ... )" if the inner
+    # query refers to the same table. To work around this we wrap the IN body in
+    # another sub query.
+    WebHookLog
+      .where(
+        'id IN (SELECT id FROM (?) ids_to_remove)',
+        WebHookLog
+          .select(:id)
+          .where('created_at < ?', 90.days.ago.beginning_of_day)
+          .limit(DELETE_LIMIT)
+      )
+      .delete_all
+  end
+end

changelogs/unreleased/prune-web-hook-logs.yml

+---
+title: Prune web hook logs older than 90 days
+merge_request:
+author:
+type: added

config/initializers/1_settings.rb

@@ -338,6 +338,10 @@ Settings.cron_jobs['issue_due_scheduler_worker'] ||= Settingslogic.new({})
 Settings.cron_jobs['issue_due_scheduler_worker']['cron'] ||= '50 00 * * *'
 Settings.cron_jobs['issue_due_scheduler_worker']['job_class'] = 'IssueDueSchedulerWorker'
 
+Settings.cron_jobs['prune_web_hook_logs_worker'] ||= Settingslogic.new({})
+Settings.cron_jobs['prune_web_hook_logs_worker']['cron'] ||= '0 */1 * * *'
+Settings.cron_jobs['prune_web_hook_logs_worker']['job_class'] = 'PruneWebHookLogsWorker'
+
 #
 # Sidekiq
 #

doc/user/project/integrations/webhooks.md

@@ -6,6 +6,10 @@ Starting from GitLab 8.5:
 - the `project.ssh_url` key is deprecated in favor of the `project.git_ssh_url` key
 - the `project.http_url` key is deprecated in favor of the `project.git_http_url` key
 
+>**Note:**
+Starting from GitLab 11.1, the logs of web hooks are automatically removed after
+one month.
+
 Project webhooks allow you to trigger a URL if for example new code is pushed or
 a new issue is created. You can configure webhooks to listen for specific events
 like pushes, issues or merge requests. GitLab will send a POST request with data

spec/workers/prune_web_hook_logs_worker_spec.rb

+require 'spec_helper'
+
+describe PruneWebHookLogsWorker do
+  describe '#perform' do
+    before do
+      hook = create(:project_hook)
+
+      5.times do
+        create(:web_hook_log, web_hook: hook, created_at: 5.months.ago)
+      end
+
+      create(:web_hook_log, web_hook: hook, response_status: '404')
+    end
+
+    it 'removes all web hook logs older than one month' do
+      described_class.new.perform
+
+      expect(WebHookLog.count).to eq(1)
+      expect(WebHookLog.first.response_status).to eq('404')
+    end
+  end
+end