delete old error reports periodically, refs #4487

Change-Id: I94e75d61eaff56509dee8f00d955f0063caf5b68
Reviewed-on: https://gerrit.instructure.com/3597
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Zach Wily <zach@instructure.com>

Author: codekitchen

app/models/error_report.rb

@@ -115,6 +115,12 @@ def guess_email
     self.email
   end
 
+  # delete old error reports before a given date
+  # returns the number of destroyed error reports
+  def self.destroy_error_reports(before_date)
+    self.delete_all(['updated_at < ?', before_date])
+  end
+
   def self.useful_http_env_stuff_from_request(request)
     request.env.slice( *["HTTP_ACCEPT", "HTTP_ACCEPT_ENCODING", "HTTP_COOKIE", "HTTP_HOST", "HTTP_REFERER", 
                          "HTTP_USER_AGENT", "PATH_INFO", "QUERY_STRING", "REMOTE_ADDR", "REMOTE_HOST", 

config/periodic_jobs.rb

@@ -63,3 +63,11 @@
                                      { :priority => Delayed::LOW_PRIORITY })
   end
 end
+
+scheduler.cron '35 */1 * * *' do
+  cutoff = Setting.get('error_reports_retain_for', 3.months.to_s).to_i
+  if cutoff > 0
+    ErrorReport.send_later_enqueue_args(:destroy_error_reports, { :priority => Delayed::LOW_PRIORITY }, cutoff.ago)
+  end
+end
+